Let's talk nozzle diameter...

[cyclone]

anyone ever built a nozzle with an adjustable diameter outlet?

[sleekcrafter]

Bottom Feeder may have some input here, he has talked about this very topic before.

[wsuwrhr]

High roller was talking about this some time ago

[steelcomp]

I'm working on an idea...not sure, though, if it's worth the effort AFA what gains would be seen. That's the first thing to try and figure out.

[cyclone]

I the gains could be substantial based upon testing i did at the track with four different inserts in back to back passes.
can't wrap my head around how to build it effectively though.

[YeLLowBoaT]

I think place diverter already makes one.

[wsuwrhr]

I the gains could be substantial based upon testing i did at the track with four different inserts in back to back passes.
can't wrap my head around how to build it effectively though.
I already have an idea, I just don't know how to make it look "cool"
Brian

[rrrr]

Whoa!!!! That's enough of the jets forum!!!! :jawdrop: :jawdrop: :D

[cyclone]

I already have an idea, I just don't know how to make it look "cool"
Brian
forget cool. start with ugly and successful and worry about cool later. lets here the idea. got a drawing you dont mind making public?

[Unchained]

There was a prototype in Hot Boat mag about 10 or 12 yrs ago.
It had an adjustable nozzle ID within a small range and you could hydraulically adjust the vertical height also without changing the angle.
There was a lot of hyd. lines and linkages to it.
It was pretty high tech looking and that's gotta be worth a couple mph right there. :rolleyes:
As I recall the nozzle looked somewhat like a jet engine nozzle.
I'll do some searching in the magazine pile.

[George Pataki]

Mark I think it was called the robo summtin.???????
I've been lookin for a picture for a while. also have some ideas, But thats just another project that I've put on the back burner.

[67weimann]

Place Divertor makes the FTN(Fine Tune Nozzle) ... so you can change nozzle diameter. Not on the fly adjustments but make a pass change nozzle inserts and make another pass. They offer various nozzle inserts...http://www.placediverter.com/index.php?page=details&pid=65

[cyclone]

Place Divertor makes the FTN(Fine Tune Nozzle) ... so you can change nozzle diameter. Not on the fly adjustments but make a pass change nozzle inserts and make another pass. They offer various nozzle inserts...http://www.placediverter.com/index.php?page=details&pid=65
Thanks for the link. that's what im talking about but it would be adjustable on the fly. swapping nozzle inserts does effect the boat's performance to a degree but i havent found one that is perfect. its so far been a compromise between holeshot and top end performance.
i'm thinking of something that i could adjust as the boat is running like on a fighter jet engine.

[cyclone]

There was a prototype in Hot Boat mag about 10 or 12 yrs ago.
It had an adjustable nozzle ID within a small range and you could hydraulically adjust the vertical height also without changing the angle.
There was a lot of hyd. lines and linkages to it.
It was pretty high tech looking and that's gotta be worth a couple mph right there. :rolleyes:
As I recall the nozzle looked somewhat like a jet engine nozzle.
I'll do some searching in the magazine pile.
you dont happen to have that issue of the mag do you?

[67weimann]

damn gatting all complicated and shit I see....Good luck man. Hope it works out for you...

[cyclone]

i was hoping it wouldn't be too complicated. lol

[67weimann]

Yeah, I wish everything was just an easy bolt on...except for then everyone would have one...although you have me thinking of a way to do this...things that make you go "hmmmm":idea:

[YeLLowBoaT]

So what your looking for is something like the back of a jet engine... I'm wondering... would it have to be round? It would be fairly ez to make a it in say a recrtangle, you just would have to figure how to blend the transition form round... Still ether it making something more square or a flater spray pattner would be fairly simple to make.

[wsuwrhr]

not a chance.
got a drawing you dont mind making public?

[steelcomp]

Mike, what were the performance gains you noticed, or how do you see it being advantageous? I understand the principal of different nozzle sizes, just still not sure the hassle would be worth the benefit. There's so many other fine tuning that can be done. What would you say the range of adjustment would need to be?

[steelcomp]

not a chance.Pretty complicated deal to make something adjustable (enough) that maintains some kind of effecient shape. I'm keepin mine under my hat.

[YeLLowBoaT]

You know I seem to recall some one making a ~ 4" varaible venterui for high presure apps. ( back when I use to work for a custom aquarium manufactor...) I want to say it had some type of "pie shape " cuts that inter locked locked some how...( simlar to a jet engine) now if I could only remember who made it...

[blue wonder]

Thanks for the link. that's what im talking about but it would be adjustable on the fly. swapping nozzle inserts does effect the boat's performance to a degree but i havent found one that is perfect. its so far been a compromise between holeshot and top end performance.
i'm thinking of something that i could adjust as the boat is running like on a fighter jet engine.
i got one for ya...we screwed a nozzle up chucking it up in a four jaw on the lathe and obolnged it...from top to bottom it is a 3.130 and from side to side it is a 3.100....sounds retarded but its what im running right now...at phoenix this year i tried a straight 3.125, a 3.100, and a 3.090...and oddly enough the screwed up one performed the best..its kinda weird because we tried opening it up and pinching it to make it run out the back door a little harder and all it did was fall off on the big end and the thing wouldnt leave???..go figure???...i dont know why but that damn thing works the best for my boat.

[cyclone]

Tony were you running a launch controller during the passes you swapped nozzles and did the weather change much?

[cyclone]

Mike, what were the performance gains you noticed, or how do you see it being advantageous? I understand the principal of different nozzle sizes, just still not sure the hassle would be worth the benefit. There's so many other fine tuning that can be done. What would you say the range of adjustment would need to be?
in my application i'd think i'd need a range of at least 3.060 to 3.125-inch
as for the gains, i'd hate to put info out there that might not be correct for everyone.
incremental changes made noticable improvements on one side of the coin and hurt the other, which is what makes me think that if you could holeshot the boat with the water coming out at a certain diameter nozzle and then change it later on in the run, say with a timer, that the boat would respond positively.

[Cs19]

in my application i'd think i'd need a range of at least 3.060 to 3.125-inch
If you had something that could change during a run, id look at going for a broader range. 3.06 and 3.125 are good all around nozzles.

[MikeF]

I've got the old brochure somewhere. I'll have to dig it out. :mix:

[Aduner2]

Many years ago(early 80's) at the LA Boat Show was a protoype pump with a hydraulicly controlled droop, up/down trim, and variable nozzle system. It was blue anodized on the back of a 21 crusier. Most awsome machining I've seen at the time. I believe an Eliminator 19' daytona was at the show with this pump mod also in the Eliminator booth. I think Dana Marine (billet stuff) was involved with it. Very innovative and very expensive.

[steelcomp]

in my application i'd think i'd need a range of at least 3.060 to 3.125-inch
as for the gains, i'd hate to put info out there that might not be correct for everyone.
incremental changes made noticable improvements on one side of the coin and hurt the other, which is what makes me think that if you could holeshot the boat with the water coming out at a certain diameter nozzle and then change it later on in the run, say with a timer, that the boat would respond positively.My guess is that a larger nozzle on launch would be like "low gear"...big volume, less velocity, then narrow it down as you go down the track..."high gear"...higher velocity, less volume. Might make it easier to feed the pump at higher speeds with less water requirement.

[sdpm]

Many years ago(early 80's) at the LA Boat Show was a protoype pump with a hydraulicly controlled droop, up/down trim, and variable nozzle system. It was blue anodized on the back of a 21 crusier. Most awsome machining I've seen at the time. I believe an Eliminator 19' daytona was at the show with this pump mod also in the Eliminator booth. I think Dana Marine (billet stuff) was involved with it. Very innovative and very expensive.
It was Dana. Very trick piece.

[Dana Marine Products]

We still have that product on our wall. Back then, due to an expensive price tag, a lack of sales determined it's current position, not being manufactured. It had three functions, an adjustable droop snoot, an adjustable nozzle (similar to Place), and an adjustable inside diameter nozzle outlet. The coolest part is, we engineered a computer system that controls the entire unit. It allows up to 6 different settings. With the touch of one button you could select custom pre-determined settings of all three functions. Go from ski to race to high rooster tail to cruising or whatever settings you can dream of with the touch of one button. We also made a version that had four functions, it featured all of the above plus a hydraulic ride plate. The ride plate function was then included in all the computer settings. It's a very cool part, and it very well could re-surface in the near future. We've had alot of inquiries on it, and I think the "jetboat" market of today may be able to absorb this type of part.

[blue wonder]

Tony were you running a launch controller during the passes you swapped nozzles and did the weather change much?
no i dont run a launch controller...the alt. was within 500 feet during the runs i changed nozzles around

[Duane HTP]

I have made two different versions of a changable nozzle size while under way. Both worked fairly well under a load, but had to be awfully careful of sand sticking them. They did make a little difference, but could never figure out how to make them at a price that the jet world would be willing to pay. I've probably still got the prototyoes lying around the shop here somewhere.

[HotRod Sprint]

We still have that product on our wall. Back then, due to an expensive price tag, a lack of sales determined it's current position, not being manufactured. It had three functions, an adjustable droop snoot, an adjustable nozzle (similar to Place), and an adjustable inside diameter nozzle outlet. The coolest part is, we engineered a computer system that controls the entire unit. It allows up to 6 different settings. With the touch of one button you could select custom pre-determined settings of all three functions. Go from ski to race to high rooster tail to cruising or whatever settings you can dream of with the touch of one button. We also made a version that had four functions, it featured all of the above plus a hydraulic ride plate. The ride plate function was then included in all the computer settings. It's a very cool part, and it very well could re-surface in the near future. We've had alot of inquiries on it, and I think the "jetboat" market of today may be able to absorb this type of part.
I'd bet that Mikey's droolin about now, with unstoppable wood. :D
Rod

[SmokinLowriderSS]

Apparently Marinejettech does something like this, just found it. They use a rectangular nozzle tho with variable sides (also for steering), an adjustable plate on the intake (to close off excess opening), and a variable pitch axial impeller (panther style). This is computer controlled and HAS to be super-spendy. :jawdrop:
http://marinejettech.com/media/Jordan%20Intellijet%20MACC%202005.pdf (Intelijet)

[cyclone]

my mailbox has been blowin up with guys coming out of the woodwork with prototypes. so far the consensus has been that none ever came to market with them because of the cost involved. if i get to see any of them and if they agree, i'll post up some pics.

[Cs19]

my mailbox has been blowin up with guys coming out of the woodwork with prototypes. so far the consensus has been that none ever came to market with them because of the cost involved. if i get to see any of them and if they agree, i'll post up some pics.
Get one for the Ultra mike, would be cool to see you make one work.
Chris.

[bottom feeder]

I posted some stuff some time ago on this subject. You would not belive the haters that showed up with torches and pitchforks. I have 4 working prototypes all based on differant design principals.

[flat broke]

We still have that product on our wall. Back then, due to an expensive price tag, a lack of sales determined it's current position, not being manufactured. It had three functions, an adjustable droop snoot, an adjustable nozzle (similar to Place), and an adjustable inside diameter nozzle outlet. The coolest part is, we engineered a computer system that controls the entire unit. It allows up to 6 different settings. With the touch of one button you could select custom pre-determined settings of all three functions. Go from ski to race to high rooster tail to cruising or whatever settings you can dream of with the touch of one button. We also made a version that had four functions, it featured all of the above plus a hydraulic ride plate. The ride plate function was then included in all the computer settings. It's a very cool part, and it very well could re-surface in the near future. We've had alot of inquiries on it, and I think the "jetboat" market of today may be able to absorb this type of part.
I know there were some brochures for this setup floating around... care to post one up? I believe the unit I remember seeing was either blue PC or ano. If the numbers from HB and my memory can be trusted, the thing made a measureable increase in the performance of the test boat. Every couple of years this subject gets touched upon and then forgotten. I'd love to see some pics again, if for no other reason than to refresh my memory.
Chris

[Old Guy]

Is anybody, who really knows (from personal experience), willing to share data regarding actual performance enhancement? The question is not if it can be done. The question for me would be.....is it worth the bother.....forget the cost. Does the change "on the fly" make any important difference? How much difference can it make?
old

[steelcomp]

Is anybody, who really knows (from personal experience), willing to share data regarding actual performance enhancement? The question is not if it can be done. The question for me would be.....is it worth the bother.....forget the cost. Does the change "on the fly" make any important difference? How much difference can it make?
oldExactly what I was trying to ask earlier. My guess is that since this isn't something new, if it made that big a difference, you'd see at least one or two out there. Too many other adjustable factors that seem to make bigger differences.

[Dana Marine Products]

We've produced 10 nozzle units that are out there. The one that was in HB was blue ano. I'll try to dig up the HB article. This part was initially designed to be a part of another much larger scale jet project. Some questions have arose as to how well it would benefit a normal jet application. If you're already running a place diverter, the difference could be minimal. It really depends on the boat, every boat reacts different to these types of things. The concept is that it would give you the ability to make several adjustments from the drivers seat while underway. These adjustments could very well take your boat to another level. In some boats, the differences may not be noticable. But in others, (probably in most cases) it will be a noticable increase in take off, mid range, and top end.
I can't say too much about this at this time, but what I can say is that within the next 12-24 months there will be a revolution in the jet drive industry. We have already produced and ran something that will change the way jetboats are viewed. Let's just say there's alot of room for improvement over all current jet drive designs.

[wsuwrhr]

This is good news.
After 30+ years of little or no design changes I would have to agree.
I think the bigger problem now is the jet drive it is a niche market.
Most people with jet boats just want it to work for as cheap as possible.
Most of the marine money goes into bling or the outdrive/bigger boat market.
Brian
Let's just say there's alot of room for improvement over all current jet drive designs.

[Cs19]

I can't say too much about this at this time, but what I can say is that within the next 12-24 months there will be a revolution in the jet drive industry. We have already produced and ran something that will change the way jetboats are viewed.
Woah, looking forward to seeing this big secret being revealed.

[1978 Rogers]

So I take it, this is a product for racers or big azz engine jet boat guys. Not for the typical weekend water skiier?

[Dana Marine Products]

Actually, this product will be aimed directly at big manufacturing, not just the race crowd. It will probably greatly benefit the race crowd. This will be a product that will put a new face on jet boats and some of their known cons. I'll keep everyone up to speed.

[MudPumper]

Is anybody, who really knows (from personal experience), willing to share data regarding actual performance enhancement? The question is not if it can be done. The question for me would be.....is it worth the bother.....forget the cost. Does the change "on the fly" make any important difference? How much difference can it make?
old
I think Mike would be gearing this toward a race application. Being able to adjust the nozzle on the fly to get a great holeshot off the rope and then tune it to obtain speed down the track. With the nozzle inserts available now, you either get a good holeshot and sacrifice top end or vise versa or you have to settle for something in between.

[HammerDown]

I can't say too much about this at this time, but what I can say is that within the next 12-24 months there will be a revolution in the jet drive industry. We have already produced and ran something that will change the way jetboats are viewed. Let's just say there's alot of room for improvement over all current jet drive designs.
Something is needed...more MPH at less RPM.
Or one word...efficiency

[HotRod Sprint]

Something is needed...more MPH at less RPM.
Or one word...efficiency
Which also means fuel economy.
Rod

[Jet Hydro]

We are working on a jet part that a computer adjusts on the fly that makes a large difference in performance. Cant tell ya what it is but it will be cost efficient.:idea:
Just kicking out a bone for you to pick at. :) :D

[bottom feeder]

The gains I have seen from nozzel research are from a control stand point. With a given impeller spinning a given RPM with a known water density their is a ideal nozzle diameter. The adjustable nozzel has lead me to other areas that give a much higher return. An example would be the use of larger impellers (9.25 and 9.5) in conjuction with larger nozzels. I feel this has to do with the amount of movement put into the water.
I ran tests over the summer on impeller cutting. As i seen it, the cutting down of the impeller to free up RPM was not the best way to gain RPM as it removed motion imparted on the water and inlarged what I call the reversion window for lack of a better term. The test I ran used the same same uncut 9.25 impeller, bowl that I detailed on a CNC mill and a selection of spacers and nozzel inserts. With out cutting the impeller I managed to alter the peak RPM that my motor would pull it to by 1600 RPM. Yes their was a large diferance in boat speed as one would expect. After running one set up I would note RPM and hull speed. I then tried to disprove my thinking by taking the same impeller and bowl in their stock locations and use the more known practice of turning the impeller. I did the same tests noting RPM and hull speed. As was epected I had a large spread in hull speed. The trend that showed was the hull speed was faster with the uncut impeller at the same peak RPM. What does all this mean? Not jack But I am am not cutting up a $900. part on a hunch anymore.

[Unchained]

I posted some stuff some time ago on this subject. You would not belive the haters that showed up with torches and pitchforks.
I'm familiar with that attitude.
I posted pictures of the pump intake duct that Old Guy designed and I built and installed on my boat.
What I summarized out of the responses was, "If Jack M. or some other recognized pump expert didn't build it, how could it possibly have any merit"
That's like a famous statement made in early 1900"s that said, "everything that can be invented has been invented"
Doesn't matter though. Didn't deter me or Old Guy a bit.
Never mind that I ran it for 50+ hours and at speeds over 115 and it prevented the back of the boat from hopping on shutdown. Results didn't seem to be a concern.
It's still on the boat today and will remain on.

[cyclone]

The gains I have seen from nozzel research are from a control stand point. With a given impeller spinning a given RPM with a known water density their is a ideal nozzle diameter. The adjustable nozzel has lead me to other areas that give a much higher return. An example would be the use of larger impellers (9.25 and 9.5) in conjuction with larger nozzels. I feel this has to do with the amount of movement put into the water.
I ran tests over the summer on impeller cutting. As i seen it, the cutting down of the impeller to free up RPM was not the best way to gain RPM as it removed motion imparted on the water and inlarged what I call the reversion window for lack of a better term. The test I ran used the same same uncut 9.25 impeller, bowl that I detailed on a CNC mill and a selection of spacers and nozzel inserts. With out cutting the impeller I managed to alter the peak RPM that my motor would pull it to by 1600 RPM. Yes their was a large diferance in boat speed as one would expect. After running one set up I would note RPM and hull speed. I then tried to disprove my thinking by taking the same impeller and bowl in their stock locations and use the more known practice of turning the impeller. I did the same tests noting RPM and hull speed. As was epected I had a large spread in hull speed. The trend that showed was the hull speed was faster with the uncut impeller at the same peak RPM. What does all this mean? Not jack But I am am not cutting up a $900. part on a hunch anymore.
"The trend that showed was the hull speed was faster with the uncut impeller at the same peak RPM. What does all this mean?"
makes perfect sense. if the impeller is fully loaded and you are able to turn a larger impeller the same rpm as the smaller impeller then the larger impeller will generate more thrust and therefore the boat will go faster. What i'm wondering is how you were able to get the motor revving 1600 rpm more without touching the impeller, withought taking away a significant amount of water supply to the impeller, and also making the boat faster. However you were able to do that is pretty freakin interesting to me. You said something about spacers?? care to elaborate?:)

[bottom feeder]

I'm familiar with that attitude.
I posted pictures of the pump intake duct that Old Guy designed and I built and installed on my boat.
What I summarized out of the responses was, "If Jack M. or some other recognized pump expert didn't build it, how could it possibly have any merit"
That's like a famous statement made in early 1900"s that said, "everything that can be invented has been invented"
Doesn't matter though. Didn't deter me or Old Guy a bit.
Never mind that I ran it for 50+ hours and at speeds over 115 and it prevented the back of the boat from hopping on shutdown. Results didn't seem to be a concern.
It's still on the boat today and will remain on.
Old guy is sharp! I remember that. Well enough that I have ran the Scoop pretty much solved the overcharge on shut down:D Try and get a 13 foot hull to shut down nice and predictable.

[bottom feeder]

cyclone,
As you have figured out it was done with spacers. They were placed between the sution housing and bowl. I would love to take credit but a freind of mine showed me the concept. We run into lock up issues much the same as what are seen in torq converters. Slighty differant vicositys and clearances but it will still approch lock up or "stall" with a nozzle that is to small to flow the required volume. If you are running a DA system and see a constant rise in bowl pressure and a decline in suction housing pressure what is going on?

[bottom feeder]

Mike
Yes the larger impeller will move more water. But it may not create as much overall thrust. Thrust is greatly dependant on the nozzel dia. Just for simplicity Mass, volume and velocity = Thrust. If the weight of the water moved is the mass. Is the impeller, RPM and nozzle diameter the volume and velocity? Will the impeller with enough motor turning it provide more water than the nozzle can release?
I have a lot of fun messing with this stuff.

[cyclone]

Mike
Yes the larger impeller will move more water. But it may not create as much overall thrust. Thrust is greatly dependant on the nozzel dia. Just for simplicity Mass, volume and velocity = Thrust. If the weight of the water moved is the mass. Is the impeller, RPM and nozzle diameter the volume and velocity? Will the impeller with enough motor turning it provide more water than the nozzle can release?
I have a lot of fun messing with this stuff.
Right. i was referring to a pump where the nozzle diameter was fixed. smaller impeller moves less water than the larger impeller and if they both turn the same rpm, the larger impeller will make the boat move faster because it will produce more thrust as long as the water supply is adequate.

[cyclone]

cyclone,
As you have figured out it was done with spacers. They were placed between the sution housing and bowl. I would love to take credit but a freind of mine showed me the concept. We run into lock up issues much the same as what are seen in torq converters. Slighty differant vicositys and clearances but it will still approch lock up or "stall" with a nozzle that is to small to flow the required volume. If you are running a DA system and see a constant rise in bowl pressure and a decline in suction housing pressure what is going on?
so you moved the bowl away from the impeller creating a larger area and this necessitated a larger nozzle outlet? how much spacer and how much affect did it have? at what point did you decide that you needed to change the nozzle diameter? our applications are likely different because i'm looking for the quickest holeshot possible but there's probably a lot to be learned by the testing you are doing.
got any photos of your pump?

[MikeF]

Found the brochure, but can't scan them cause the scanner ain't workin.:rolleyes:

[cyclone]

Found the brochure, but can't scan them cause the scanner ain't workin.:rolleyes:
call busby and see if he's got a scanner.

[MikeF]

call busby and see if he's got a scanner.
PM his #, I do not have the latest one.:)

[MikeF]

Going over there now. Be up soon.

[cyclone]

i love it when a plan comes together.

[77Woodbridge]

It sounds like there are a few functional models available, but the R&D ROI killed its commercial viability. The next questions in my mind are:
1) What will the market bare for a stock production piece (Aussie/Canada/US)
2) Can it be manufactured with 100% Aussie/Canadian/American parts and labor at 50% market
3) Will all prinicples surrender claims to intellectual property for rights
I would be willing to invest more than a little in a product if the above 3 are there.

[bottom feeder]

The amout of spacer is quite small. The bowl spacers were .03 incriments ( to coarse) from .06 to .180. Moving the bowl out gained RPM. I would then go to the nozzel for the best speed.

[MikeF]

http://www.***boat.com/image_center/data/500/153page1_1.jpg
http://www.***boat.com/image_center/data/500/153page2_1.jpg
http://www.***boat.com/image_center/data/500/153page3_1.jpg
http://www.***boat.com/image_center/data/500/153Page4_1.jpg

[cyclone]

they guys that are on this forum probably aren't gonna be at the races you're at. i wouldnt worry about giving away the secrets.
so basically moving the bowl out away from the impeller .06 to .180 increases rpm. ok i get that.
what happened to the holeshot by doing that? did you add the spacer and leave the nozzle the same diameter? or did you add the spacer and open up the nozzle at the same time?

[BUSBY]

i love it when a plan comes together.
MikeF has been here and gone ... should be posting up soon ...
now, back to my movie ...

[BUSBY]

oops ... see how fast he is?

[bottom feeder]

Now you are giving away secrets:mad:
You are supose to perfect them and take them to the races and kick everyones ass and make them wonder WTF.....:D
No secrets amoung frends :sqeyes: Their are lots of tricks in the bag yet.

[cyclone]

http://www.***boat.com/image_center/data/500/153page1_1.jpg
http://www.***boat.com/image_center/data/500/153page2_1.jpg
http://www.***boat.com/image_center/data/500/153page3_1.jpg
http://www.***boat.com/image_center/data/500/153Page4_1.jpg
holy crap this is exactly what i was asking about. well not exactly. i dont know whether or not i'd need the ability to raise or lower the droop from the steering wheel at speed. but the adjustable nozzle orofice is cool.
is this the dana piece?

[MikeF]

oops ... see how fast he is?
Should be........
oops ... see how fast he is!
:D

[bottom feeder]

Moving .18 for me was worthless as it just over spun the motor. .03 over zero gained me 400 RPM. I seen big gains in holeshot when I went to the 9.5 impeller and 3.312 nozzle.

[steelcomp]

holy crap this is exactly what i was asking about. well not exactly. i dont know whether or not i'd need the ability to raise or lower the droop from the steering wheel at speed. but the adjustable nozzle orofice is cool.
is this the dana piece?OK...that solves sthat mystery, but I'm wondering how important it is to keep the nozzle round, or at least symetrical. IN teh above system, you're really not reducing the dia. of the nozzle, you're just changing the volume by altering it's shape. My idea is to change the dia. keeping some kind of concentricity. I'd like to see a comparison to an altered opening, like the one above, and a perfectly round one of the same area.

[Dana Marine Products]

Thats it!

[Old Guy]

OK...that solves sthat mystery, but I'm wondering how important it is to keep the nozzle round, or at least symetrical. IN teh above system, you're really not reducing the dia. of the nozzle, you're just changing the volume by altering it's shape. My idea is to change the dia. keeping some kind of concentricity. I'd like to see a comparison to an altered opening, like the one above, and a perfectly round one of the same area.
I think that the most efficient nozzle would be one that requires the least amount of water to change direction to get through it. For example, to go from round to square requires a large change in flow direction for a large amount of water. Not good.
If you squeeze the diameter and maintain it's concentricity, then the entire circumference will drag on the laminar flow going through it. The velocity will increase as the diameter gets smaller. The bowl pressure will increase.
One might assume that the increase in bowl pressure indicates greater flow through the pump. This would be true if there had been a change in rpm, a different loader (resulting in higher intake pressure), a tighter impeller clearance.....but if the bowl pressure got higher from a nozzle getting smaller....you probably have less flow.
The boat goes faster if you increase the pounds per second of the water going through the pump.
The velocity of the water going through the pump must be greater than the velocity of the boat by a factor of ?????...I have no clue. But it's real important.
Disregarding the efficiency of the hull, I think there is probably a relationship between the weight of the water going through the pump and the weight of the boat going through the water. Once the hull is on plane, it takes less power to keep it there than it took to get it there.
There is an optimum pump flow/nozzle velocity for every amount of hp that can be offered that will result in the "most you gonna get" out of that boat with that motor.
All of the above is being posted in the interest of stimulating productive thought. I type with 2 fingers. I hope it helps somebody.
old

[cyclone]

I think that the most efficient nozzle would be one that requires the least amount of water to change direction to get through it. For example, to go from round to square requires a large change in flow direction for a large amount of water. Not good.
If you squeeze the diameter and maintain it's concentricity, then the entire circumference will drag on the laminar flow going through it. The velocity will increase as the diameter gets smaller. The bowl pressure will increase.
One might assume that the increase in bowl pressure indicates greater flow through the pump. This would be true if there had been a change in rpm, a different loader (resulting in higher intake pressure), a tighter impeller clearance.....but if the bowl pressure got higher from a nozzle getting smaller....you probably have less flow.
The boat goes faster if you increase the pounds per second of the water going through the pump.
The velocity of the water going through the pump must be greater than the velocity of the boat by a factor of ?????...I have no clue. But it's real important.
Disregarding the efficiency of the hull, I think there is probably a relationship between the weight of the water going through the pump and the weight of the boat going through the water. Once the hull is on plane, it takes less power to keep it there than it took to get it there.
There is an optimum pump flow/nozzle velocity for every amount of hp that can be offered that will result in the "most you gonna get" out of that boat with that motor.
All of the above is being posted in the interest of stimulating productive thought. I type with 2 fingers. I hope it helps somebody.
old
Thanks for your input. what's your take on the whole spacing the bowl out away from the exit side of the impeller? is there a benefit there if the nozzle diameter remains the same? does it matter that moving the bowl away from the impeller increases the gap between the stuffer and exit side of the impeller?
so many questions...

[Old Guy]

Thanks for your input. what's your take on the whole spacing the bowl out away from the exit side of the impeller? is there a benefit there if the nozzle diameter remains the same? does it matter that moving the bowl away from the impeller increases the gap between the stuffer and exit side of the impeller?
so many questions...
If the nozzle diameter is not changed, and the bowl pressure increases, there has gotta be more water going through the pump.
As far as the bowl/impeller spacing relationship?? No clue. All the dimensions of our jet pumps had an origin. Considering the fact that the original Berkley pump was designed and built as an irrigation pump. I can't even begin to guess where, and why our pumps are what they are.
If you are going to try to improve pump efficiency/boat speed, you really should hold no pump part sacred. They are all suspect. Each part should be challenged and required to prove itself optimum......or not. A jet pump is a very inefficient way to propel a boat. I think it does not need to be that way.
If you set about to prove that a jet pump is the way it is because it has to be the way it is, .....let's just say that any change that is made should change the performance of the pump. Now comes the fun part. You make up a detailed story as to why the change you made resulted in the performance change that was noted. Now prove your story is true.
You continue doing that until you can predict EXACTLY what effect any change will have, and why. Now you should be able to design a new (way better) jet pump.
old

[blue wonder]

Moving .18 for me was worthless as it just over spun the motor. .03 over zero gained me 400 RPM. I seen big gains in holeshot when I went to the 9.5 impeller and 3.312 nozzle.
im just a little confused...maybe you can answer a couple questions...you kept the same size impeller and the same size nozzle and moved the bowl back .030 and picked up 400 rpm???...you also said you found 1600 rpm...what did you do to pick all that up???...also i am running a b/c sized impeller right now...is the theory the same with a smaller impeller like that or do you have to run the big impeller???...i would love to pick up about 500-800 rpm!!!

[Unchained]

The pictures of the Directional Jet Thruster unit look good but that is not the one that I remember from the old Hot Boat mag.
The one I seen adjusted the nozzle diameter directly as well as the vertical nozzle postion.
I really need to dig that up now.

[Old Guy]

For those of you who have the time, money, interest, and determination to pursue this subject, here is a sample of the type of format that I recommend. This will help to maintain focus and lead to solid gains in the state of the art.
Hp = 500 hp @ 5K rpm
Engine rpm = 5000
Suction pressure = 35 psi
Bowl pressure = 50 psi
Nozzle velocity = 8000 fpm (est.)
Nozzle dia. = 4"
Boat speed = 50 mph (GPS)
Obviously, these are bogus numbers. It's the concept that's important. When you make a change, it will cause other changes. It's very important to know what changed and WHY. This will enable you to stay focused and productive.
Note: A basic truth that's not going to change remains. For any given amount of water going through a jet pump, the speed of the boat will increase as you increase the velocity of the water coming out of the nozzle. However, as you decrease nozzle dia. to cause an increase in velocity, you will arrive at a point where the smaller nozzle size restricts the flow of water through the pump. This is where the boat starts going slower with any further decrease in nozzle size.
Some General said it long ago, "You gotta get there first with the most".
old

[Old Guy]

Just a comment on bowl pressure ... Most 'Tuned' 1/4 Mile Drag Boats are running bowl pressures on the order of mid to high 200's on up to 350 psi with the Record Holding Boats running pressures right around 350 +/- a few psi.
We run ours 'somewhat' higher than that ... we've seen pressures slightly higher than 500 psi, but, have typically 'Blown The Tail' at the 'Big End' of the 1/4 when we've experienced those kind of pressures ... Definately Not A Good Thing! With our current pump setup, I like to run our bowl pressure between something like 390 to 460 psi with a 3.150 nozzle. I know that's a bit high for most racer's liking, but, the ever so slight pump reversion that I believe we get at those pressures helps lift/'free up' the back of the boat ever so slightly without making it Dangerous in terms of handling.
I'll add that I don't think 'Lake Racers'/Recreational Boats should run bowl pressures as high as we do ... those boats should have their bowl pressures in the 300 to max 350 range as over, that the potential for blowing the tail with Serious Consequences Is Very Real.
Wouldn't it be interesting to know the actual gpm of a real race pump. Those numbers have got to translate into a huge gpm. Thanks for posting some real numbers. I can understand why a lot of guys keep all that stuff to themselves. Of course, the concept is exactly the same regardless of the numbers involved. It's the effect of making any change that guides one in the proper direction.
It's also important to understand that the increase in boat speed is not going to be equal to incremental change in hp or pump efficiency. As the wetted surface changes, the wind resistance changes, and a few other variables change, many factors influence the behavior and speed of a boat.
old

[Unchained]

Just a comment on bowl pressure ... Most 'Tuned' 1/4 Mile Drag Boats are running bowl pressures on the order of mid to high 200's on up to 350 psi with the Record Holding Boats running pressures right around 350 +/- a few psi.
Well I've seen 380#, does that mean mine could be a record setter ?
O boy I'm all excited now. :rollside:
I guess I should have taken a picture of the gauge to prove it.
I'm running a 3.062" nozzle which is what they ran on R & D Express which was the best running N/A Stealth I've ever seen.
I didn't know what bowl pressure I wanted to be at but Jack Mclure told me at the 05 WF's that there was NO WAY my motor could turn a AA impeller at 7000 rpm so I should take a bowl pressure reading, Like it was sucking in air or something. So I got a reading. What now ?

[cyclone]

in terms of telling whether or not you motor is really turning a AA at 7,000 rpm with adequate water supply to the impeller.....an inlet pressure reading would be more helpful than bowl pressure.
and since the variations between sensors and where they are located can change readings drastically, you should look at pressure readings on your own boat for trends when you make hardware changes, not to compare them to other data gathered from other boats.

[Cs19]

So I got a reading. What now ?
Perhaps you should get an inlet pressure reading.:idea:

[Unchained]

Perhaps you should get an inlet pressure reading.:idea:
I've had a gauge on it from the start.
Last time I checked it was in the 40# area.
It's hard to read when your going fast. I wanted to get a pressure sender to read 0-5 volts so I can tie it into the datalogger.

[Unchained]

in terms of telling whether or not you motor is really turning a AA at 7,000 rpm with adequate water supply to the impeller.....an inlet pressure reading would be more helpful than bowl pressure.
Funny you should say that.
Jack told me to go by the bowl pressure because that's what pushes the boat.
I told him what I had for intake pressure, I guess he didn't think it was real.
I have a lot of respect for Jack and all of his accomplishments but I was a little miffed at the time.

[Cs19]

Last time I checked it was in the 40# area.
It's hard to read when your going fast
I would call it impossible to get useable a reading, taking a quick look at a guage during a hard pass isnt gonna cut it with a fast tunnel hull. IMO you need to see RPM, inlet pressure and bowl pressure from A to B.

[Old Guy]

I wonder if anybody measures nozzle velocity. After all, it's the speed of the water leaving the nozzle that makes the boat go.
If you had that information.......and a couple of bucks......you could probable get a cup of coffee......or a beer.....somewhere.
Merry Christmas
old

[bp]

I would call it impossible to get useable a reading, taking a quick look at a guage during a hard pass isnt gonna cut it with a fast tunnel hull. IMO you need to see RPM, inlet pressure and bowl pressure from A to B.
i remember having a gauge with a telltale on it. that was pretty much useless for tuning because you had no idea where max pressure occurred, or why.
unchained, when you're saying 7000/AA, there are more than a couple of reasons (comparisons) why you would get a blank stare. i.e., 1200+hp engines turning A's or B's (and in some cases, C's) <7000. i've seen a lot of data, but the one example i'll mention is the biz; that engine made 1250 on two different dynos, and turned an A 6650-6660, with the engine at peak hp rpm. ask ubfj what his rpm/impeller are, on/off nos. a legitimate 7000/AA would equate to a LOT more hp than 1200.
as cs said, those three data points are invaluable to really get an idea of what's going on.

[Unchained]

All that recording, comparing, and adjusting of pump data is something that I never spent much time on. Where I boat, which is the most popular place in the state for performance lake boats, I'm in front now. Just ask.....me. :D
If I boated with the 6th street crowd it would be a whole lot different picture. :idea:
I spent a lot more time with engine data and fine tuning the EFI maps.
Any points I wanted to make with this project involved turbo's and EFI more than what the Stealth hull could do. Many others already did that.
I remember at the point where I was bumping up the accelleration enrichment. WOW did I get an eye opener. I have it so I can just flatfoot the pedal from a dead idle now. I never had that with carbs. Only someone who knows port injection can appreciate the throttle response that you get. The MAP sensor can react way faster than your foot can slap the pedal down.
Now someone can respond that you don't need or want that much throttle response. :rolleyes:

[DEL51]

Mark,MPD set me up with a data recorder that I will be hooking up in the coming months. The neat part was the calibrated sensor package. You may want to inquire about a couple of these for your application. I have 2 taps so far ,on the drive. Timinator had talked about pressure points on the suc side and not settling with the "O" in the suc housing, as this is an avreage and might not be the best way.I think there has been many threads on this, so what, lets rehash as it,as it will benefit me. This is a great thread,Kudos to Cyclone. CS-19 and Bear, I would like to know if the data your recording shows more charge in the suction at speed vs half track, etc. Merry Christmas

[Cs19]

I spent a lot more time with engine data and fine tuning the EFI maps.
Any points I wanted to make with this project involved turbo's and EFI more than what the Stealth hull could do.
You made your point clear as day with efi like 2 years ago. We know you enjoy that efi/turbo thing.
Its like you blow everyone off when they tell you there is something odd about your RPM numbers on that AA, why is that?

[Old Guy]

You made your point clear as day with efi like 2 years ago. We know you enjoy that efi/turbo thing.
Its like you blow everyone off when they tell you there is something odd about your RPM numbers on that AA, why is that?
I think it's because Mark's making a whole lot more hp than anybody thinks he is.
old

[Unchained]

Its like you blow everyone off when they tell you there is something odd about your RPM numbers on that AA, why is that?
I don't know why I get some that don't believe it.
I have positive intake pressure above 35# which is what I was told was the minimum to fill pump voids.
I don't need my boat to ride high on pump intake overcharge (it can't) so I don't want any more intake pressure than what it takes to feed the impeller.
I checked bowl pressure and had in the mid to upper 300# range.
The boat has a drop keel factory installed by Papp.
I put in a new ultimate wear ring last season and have it properly clearanced.
I have datalogged the rpm.
http://www.***boat.com/image_center/data/520/220datalogoct05.jpg
Now if the pump had a hole in the side and was sucking air would I have bowl pressure ?
If the pump wasn't being loaded would I have intake pressure ?
I'm ready to learn something so enlighten me. :idea:

[Duane HTP]

On the RPM/AA impeller thing, I think one fact that should be looked at is the range of the torque of the two motors being discussed. I think you'll find that the turbo motor has a higher torque range. (please don't let this start the tq/hp thing).
As for the comments made about the R & D Express, and about UBFJ # 454's numbers, I can relate to them very easily. Take a look at this data run from the R & D Express at the WF a couple of years ago. This was a 132 mph run.
http://www.hi-techperformance.com/images/Suction_Time.jpg
If you'll notice the bowl pressure ran between 390 and 425 lbs. The intake pressure ran between 30 and 37 lbs. Et was in the 7's (barely). This was in a 550 lb hull with a 3.062" nozzle.

[bp]

Up until now we have been running a Legend B Impeller ... The motor is Rev Limited @ 7,700 rpm for Safety ... w/o n2o, on C-16 only, we've been spinning the impeller @ slightly above 6,800 rpm ... with a 250 shot, rpm's go up to just @ 7,200 rpm ... the Dyno'd (some 50 pulls from two seperate sessions) Hp of the motor, 'Ms. MoneyPenny', on C-16 alone is between 1,250 & 1,275+.
As far as intake charge thru the 1/4 Mile, in the past once on the move the pressure steadily grew from zero throughout the run and has been recorded above 90 psi (occasionally even above 100 ... at which point we've 'Blow The Tail').
in sum, this is 1500hp to spin a B (not an AA) slightly over 7k
As for the comments made about the R & D Express, and about UBFJ # 454's numbers, I can relate to them very easily. Take a look at this data run from the R & D Express at the WF a couple of years ago. This was a 132 mph run.
If you'll notice the bowl pressure ran between 390 and 425 lbs. The intake pressure ran between 30 and 37 lbs. Et was in the 7's (barely). This was in a 550 lb hull with a 3.062" nozzle.
you don't mention power applied, but wasn't this with approximately 1600hp?
On the RPM/AA impeller thing, I think one fact that should be looked at is the range of the torque of the two motors being discussed. I think you'll find that the turbo motor has a higher torque range. (please don't let this start the tq/hp thing)..
well, it can be looked at it, but it either has the hp to turn the AA 7k, or there's something else going on there.
just for grins, tomkat ran 8.0s all weekend at the wf's, making well below the power mentioned here, spinning in the 7k range, but with much less than an AA, at around 123. granted, the boat weighs about 175 less than you mentioned, but there is nowhere near enough power to spin an AA to the needed rpm regardless of weight. UBFJ 454 weighs a lot more than 555.
i can flatfoot a 3.156 off the rope without losing bowl pressure. in fact, that's what was in when i ran the .000 in qualifying at the wf's. if the only recourse to maintain velocity off the rope is to go small, i'd say there's still more work to be done.

[Duane HTP]

you don't mention power applied, but wasn't this with approximately 1600hp?
I believe the dyno sheets read about 1402 HP.
well, it can be looked at it, but it either has the hp to turn the AA 7k, or there's something else going on there.
Yes, I suppose that it's a 620 lb boat with pretty much full interior and gas tanks might be a factor there. I have not seen inside the pump lately either.
I've seen him run several times and it is quite impressive. I would love to get a chance to put my data acquisation equipment on the boat. It would help answer some of the questions about it here.
BP, don't take offense here, I'm claimiing no numbers; Just that it is a very fast boat.

[Old Guy]

We started out here looking for the answer to a question about changing nozzle diameter "on the fly". We now know that there has been more than a little work done in pursuit of this info. A lot of time and money has been spent and there is data somewhere that illustrates the value (or lack of it) of this concept.
An adjustable "on the fly" nozzle can be produced for a price that could be afforded by those who would most benefit by using it.
So, what's it going to be? Is the concept a good one, or just not worth the bother?
Old

[steelcomp]

We started out here looking for the answer to a question about changing nozzle diameter "on the fly". We now know that there has been more than a little work done in pursuit of this info. A lot of time and money has been spent and there is data somewhere that illustrates the value (or lack of it) of this concept.
An adjustable "on the fly" nozzle can be produced for a price that could be afforded by those who would most benefit by using it.
So, what's it going to be? Is the concept a good one, or just not worth the bother?
OldI'd still like to get some input on weather or not the shape of the nozzle is as critical as the size. Reducing a nozzle's size by basically introducing an obstacle into it's bore dosen't seem very efficient. It may show usable differences between the ranges of the unit itself, but I'd like to see comparative data between a round nozzle and a "reduced" nozzle of the same area. Also, by simply changing one side of the nozzle to reduce it's size, how would you go about correlating that with a specific dia.?

[steelcomp]

On the RPM/AA impeller thing, I think one fact that should be looked at is the range of the torque of the two motors being discussed. I think you'll find that the turbo motor has a higher torque range. (please don't let this start the tq/hp thing). You make that statement and say "(please don't let this start the tq/hp thing)" "Range" has nothing to do with it, and 1200 hp @ 7000 rpm is going to have the same tq. regardless of the type of engine weather it's blown, turbo'd, NA, N20...it's just a formula. (btw...1500hp@7200rpm=1093#') If Unchained's motor is making that much more torque at 7000, then it's also making that much more HP than those other engines mentioned, which could very well be, but the torque "range" has nothing to do with it. It's called boost.

[Duane HTP]

I undserstand what you are saying. Do you understand THAT BOOST MAKES TORQUE?
I have looked everywhere for the pictures of the two different types of changable on the fly nozzles that I made but can not find them. I think possibly those pictures went out the window with the tornado.
We played with them and thought they helped some, but for unknown reasons, never had them on the clocks. If I remember correctly, I think we were afraid of a malfunction at high speed that might affect steering.

[Unchained]

Our hull stripped (except for intake & steering) weighs 485 +/- 10 #'s (+/- 10 #'s due to accuracy of scales) ... Ready to run w/Mike, close to 1,650 #'s (a few +/- ... + or -, depends on what Mike had for breakfast).
That's pretty light Jak.
My boat weighs 1,920# without me.
Mike looked like about 200# so your boat might weigh 1,450#
I'm dragging along almost 500# more than you with my lake setup.
I seen a dyno video from the guy with a similar EFI turbo engine to mine here in Mi. Same size turbos but less boost. He had over 1000# of torque at 3500 rpm. He was turning a prop and needed low end torque. He broke so many outdrives I lost count. When it held together it pushed a 24' Daytona to well over 130 mph.

[steelcomp]

I undserstand what you are saying. Do you understand THAT BOOST MAKES TORQUE?
I have looked everywhere for the pictures of the two different types of changable on the fly nozzles that I made but can not find them. I think possibly those pictures went out the window with the tornado.
We played with them and thought they helped some, but for unknown reasons, never had them on the clocks. If I remember correctly, I think we were afraid of a malfunction at high speed that might affect steering.Did your nozzles stay round when they changed size?

[Duane HTP]

One did, and the other one got veins in it like the end of an exhaust pipe as it opened. Seemed like the last one worked best. My guess is that round is better. Reasoning is you don't see firemen with square nozzles and we are really trying to do the same thing. (produce thrust). I'll keep looking. I've got a million pictures.
Going back on the roaD NOW AND WILL NOT BE ABLE TO RUN MY COMPUTER FOR A WHILE.

[bottom feeder]

Round nozzle openings are the optimal shape and the restriction area of the nozzle should be cylindericial ... note the length of the restriction is also very important in order to have good laminar, linear outflow (note, the more the laminar outflow, the more the thrust force is a linear, unidirectional force) out ot the nozzle. The 1/2 to 5/8ths of an inch of the Place Nozzle Inserts restriction are not of optimal length and do not establish a good laminar linear outflow.
If someone wants to get a better understanding of what I've said, I suggest researching Bernoulli's Equation as it applies to Incompressable Fluid Flow through a nozzle or a venturi ... The NASA Library has quite a bit on the subject of nozzles, etc. and, it's online.
This is vary good information here! Have you used the nozzle simulator online?

[MikeF]

Have you used the nozzle simulator online?
What simulator?

[bottom feeder]

Opps another slip up :D It was linked off the NASA site. Pretty cool tool to understand what UBFJ #454 had typed.
Ken F here it is
http://www.grc.nasa.gov/WWW/K-12/airplane/ienzl.html
Rockets http://exploration.grc.nasa.gov/education/rocket/ienzl.html

[bp]

I believe the dyno sheets read about 1402 HP..
was this with/without nos? how much of a shot?
Yes, I suppose that it's a 620 lb boat with pretty much full interior and gas tanks might be a factor there. I have not seen inside the pump lately either.
I've seen him run several times and it is quite impressive. I would love to get a chance to put my data acquisation equipment on the boat. It would help answer some of the questions about it here.
BP, don't take offense here, I'm claimiing no numbers; Just that it is a very fast boat.
duane, i'm certainly not offended, and i'm sure it's fast. but i've seen other boats run 128-130 followed by a pretty large steam cloud, and et reflects it. what i doubt is the AA/7k claim, for 1200-1300 hp. it is either making a LOT more hp than 12-13, it has loading issues, there's something else going on with the pump, or it's not really 7k. i'd tend to believe the 7k, so it's one of the other choices.
jak, there are other ways to get the flow straight without a longer insert.

[Duane HTP]

That was with the nitrous.
I think Unchained is making a lot more HP than that.

[Infomaniac]

What causes the "spikes" in the inlet pressure readings? Mxed flow? air and water. Interesting that the bowl pressure follows the same spikes.
I've put some thought to a variable nozzle on the fly and can remember thinking to myself years back when it came out in Hot Boat that someone beat me to it. :)

[Cs19]

Duane, You think Unchained is making more than 1400? Just want to clafiry.
Thanks.

[wsuwrhr]

So far I still like my idea better.
Much simpler too.
Brian

[Unchained]

Chris, I posted the HP calculations several pages back.
You can believe it or toss it, all the same to me.
http://www.***boat.com/image_center/data/520/220hpcalcs.jpg
Heavy Hitter figured this out for me and relayed that the calcs are quite accurate. You have the exact injector timing as well as that the O2 sensor tells what came out the pipe as compared to just pumping in a lot of fuel that the engine isn't burning or can't burn.
For those who don't know him Heavy Hitter (Wally) is an engineer by trade, a Turbo / EFI guru and has been a real help to me in learning the limited amount I have on this. A real nice guy who spent a lot of time teaching a stranger a few things.
I've met quite a few of those from this site now both in person and over the phone. :)

[Old Guy]

Duane, You think Unchained is making more than 1400? Just want to clafiry.
Thanks.
Duane said he was going away and would not have a computer for a while. On the chance he doesn't respond, I can tell you the answer is yes, quite a bit more.

[bp]

Duane said he was going away and would not have a computer for a while. On the chance he doesn't respond, I can tell you the answer is yes, quite a bit more.
well, he just posted that it was around 1400, so who's telling the truth? what is "quite a bit?" 1800, 2000?

[Cs19]

I'll buy its making 1400, I dont doubt that for a second... Im kinda half ass interested in this thread, I forgot that we already went over the HP numbers, my bad.
The only things I question here are the set up on the boat (the duct idea, etc. etc.) and the actual performance of the boat.

[Duane HTP]

What causes the "spikes" in the inlet pressure readings? Mxed flow? air and water.
That's exactly what it is. There were some small rollers on the course on that run. Those spikes you see are the waves causing different loading charteristics during the run.
well, he just posted that it was around 1400, so who's telling the truth? what is "quite a bit?" 1800, 2000?
Bp, I don't think it has anything to do with "Truth". These are just calculations and educated gusses. My guess is close to 1600 hp.
The only things I question here are the set up on the boat (the duct idea, etc. etc.)
I did the set up on the boat. (intake, shoe loader, plates,) So, of course I'm comfortable with that. I've wondered about the effect of the duct. But I've ridden in and seen the boat run and it seems to work good.
I guess the only thing to do is to talk him into coming down to my place, hook up the data recorder, and then go to the races. Otherwise we're just flapping our gums.

[steelcomp]

Chris, I posted the HP calculations several pages back.
You can believe it or toss it, all the same to me.
http://www.***boat.com/image_center/data/520/220hpcalcs.jpg
Heavy Hitter figured this out for me and relayed that the calcs are quite accurate. You have the exact injector timing as well as that the O2 sensor tells what came out the pipe as compared to just pumping in a lot of fuel that the engine isn't burning or can't burn.
For those who don't know him Heavy Hitter (Wally) is an engineer by trade, a Turbo / EFI guru and has been a real help to me in learning the limited amount I have on this. A real nice guy who spent a lot of time teaching a stranger a few things.
I've met quite a few of those from this site now both in person and over the phone. :)How does 20lbs of boost equate to 91% VE?

[bp]

I guess the only thing to do is to talk him into coming down to my place, hook up the data recorder, and then go to the races. Otherwise we're just flapping our gums.
yep.

[cyclone]

That's exactly what it is. There were some small rollers on the course on that run. Those spikes you see are the waves causing different loading charteristics during the run.
Bp, I don't think it has anything to do with "Truth". These are just calculations and educated gusses. My guess is close to 1600 hp.
I did the set up on the boat. (intake, shoe loader, plates,) So, of course I'm comfortable with that. I've wondered about the effect of the duct. But I've ridden in and seen the boat run and it seems to work good.
I guess the only thing to do is to talk him into coming down to my place, hook up the data recorder, and then go to the races. Otherwise we're just flapping our gums.
what's this "duct"? what's it do and where's it at? i must have missed the thread on it.

[steelcomp]

what's this "duct"? what's it do and where's it at? i must have missed the thread on it.It's basically a box that they built under the intake in an attempt to retain intake overcharge. seemed to work pretty well.

[cyclone]

doesn't that drag in the water?

[steelcomp]

doesn't that drag in the water?
See for yourself
http://www.***boat.com/image_center/data/500/220Duct3-med.jpg

[Old Guy]

doesn't that drag in the water?
Of course it drags. Anything you put down there is going to drag.
The question is not about drag. The question is DOES IT CONTRIBUTE ANYTHING OF VALUE THAT WOULD MORE THAN OFFSET THE LOSS FROM THE DRAG.
I guess instead of putting it out there for anyone who wanted it, we should have put a price on it. Then it would have had value. Of course it would have also been better to not publish any pics...then it would be a secret...worth more $$$$$$$.
Mark and I talked about it and decided that considering that it is a SAFETY device, it should be available to any and all who wanted it.
We will stand by that decision. You can think what ever you want. I don't know about Mark, but I will not dignify a lot of this BS with a response. You want to start right out about a red hair short of calling people liars...you're gonna have this place all to yourselves. You're damn near there now.
:)

[Cs19]

I guess the only thing to do is to talk him into coming down to my place, hook up the data recorder, and then go to the races. Otherwise we're just flapping our gums.
I agree.
Or just drop the data logger in and hit the lake. Do a few runs from a dead stop for a 1/4 mile.. Then post the speed trace's.

[Old Guy]

I agree.
Or just drop the data logger in and hit the lake. Do a few runs from a dead stop for a 1/4 mile.. Then post the speed trace's.
What happened?
You started this thread with the question about an adjustable nozzle. Now it's about Mark having to prove the strength of his motor?
Who the hell cares about Marks motor? I still would like to see some data that relates to nozzle size.
Knowing how strong Mark's motor is won't help me a bit. I don't have the $$$ to build a motor even close to Mark's motor.
I already know how strong Mark's motor is. It has not helped me in any way at all. I think it's a damn fine motor, but it's got nothing to do with an adjustable nozzle.
old

[cyclone]

Of course it drags. Anything you put down there is going to drag.
The question is not about drag. The question is DOES IT CONTRIBUTE ANYTHING OF VALUE THAT WOULD MORE THAN OFFSET THE LOSS FROM THE DRAG.
I guess instead of putting it out there for anyone who wanted it, we should have put a price on it. Then it would have had value. Of course it would have also been better to not publish any pics...then it would be a secret...worth more $$$$$$$.
Mark and I talked about it and decided that considering that it is a SAFETY device, it should be available to any and all who wanted it.
We will stand by that decision. You can think what ever you want. I don't know about Mark, but I will not dignify a lot of this BS with a response. You want to start right out about a red hair short of calling people liars...you're gonna have this place all to yourselves. You're damn near there now.
:)
Whoat easy there guy. i was curious as to what it was you guys were talking about. Pardon me for asking questions.

[cyclone]

See for yourself
http://www.***boat.com/image_center/data/500/220Duct3-med.jpg
is the biting edge of the duct in front of the biting edge of the shoe?

[steelcomp]

Seems that dog ain't huntin'.
MIght as well talk about Mark's motor and set-up. It's about as interesting.
Old...lighten up, a little.What happened?
You started this thread with the question about an adjustable nozzle. Now it's about Mark having to prove the strength of his motor?
Who the hell cares about Marks motor? I still would like to see some data that relates to nozzle size.
Knowing how strong Mark's motor is won't help me a bit. I don't have the $$$ to build a motor even close to Mark's motor.
I already know how strong Mark's motor is. It has not helped me in any way at all. I think it's a damn fine motor, but it's got nothing to do with an adjustable nozzle.
old

[steelcomp]

See for yourself
http://www.***boat.com/image_center/data/500/220Duct3-med.jpg
Did you guys ever put countersunk hardware on that thing?

[steelcomp]

is the biting edge of the duct in front of the biting edge of the shoe?If it is, it's not by much. By the way it looks, with the set-back on my pump, that thing would be hanging out the back.

[Old Guy]

Did you guys ever put countersunk hardware on that thing?
When you're trying to evaluate a concept, if countersunk screws make that much difference, you're wasting you're time.
This thing is supposed to help keep a boat right side up when it's decelerating at high speed. There's nothing sophisticated about it. It's a concept......put out there for those who can work with concepts. If it works like it's supposed to work, it could keep somebody alive.
If the concept works for you, a little streamlining (blending etc.) to reduce drag would probably be a plus. For those of you making way over 1000 hp, do whatever makes you feel good.
What happened to nozzles?

[Cs19]

What happened?
You started this thread with the question about an adjustable nozzle. Now it's about Mark having to prove the strength of his motor?
Who the hell cares about Marks motor? I still would like to see some data that relates to nozzle size.
Knowing how strong Mark's motor is won't help me a bit. I don't have the $$$ to build a motor even close to Mark's motor.
I already know how strong Mark's motor is. It has not helped me in any way at all. I think it's a damn fine motor, but it's got nothing to do with an adjustable nozzle.
old
Nothing happened. You seem like your about to blow a gasket though. :confused:
First of all, I didnt start the nozzle thread.. I'm personally not too interested in the adjustable nozzle, got other things on my plate that Im excited about, but I'd like to see someone develop one. That would be a fun project to take on. Id be interested in helping out in anyway possible if someone wanted to take a shot at it.
Next..Im with you Old guy...I'm so burnt on talking about the turbo motor I cant even tell you. If its 2000 hp thats great, Im not asking him to prove anything, he decided to try and prove it.
Ive said it before and Ill say it again, I only question the actual performance of the boat, and now that you guys are saying it makes 1600 horsepower, Im really questioning the performance. Problem is everytime we get to talkin' about the performance of the boat we end up talking about efi and injectors and fuel curves and stuff.:(
Do those socket head cap screws create any drag?

[Cs19]

So let me understand the duct here.
Its only purpose is to help the boat on shutdown where these things tend to be a handful.. In so many words it keeps the overcharged intake from upsetting the tail of the boat during shutdown..Correct?

[Old Guy]

Just a little side note here. If you're interested in Mark's motor, it would make a very interesting thread. I would suggest not running your mouth very much before you see what's on the table.
THIS is supposed to be about adjustable nozzles.

[Old Guy]

So let me understand the duct here.
Its only purpose is to help the boat on shutdown where these things tend to be a handful.. In so many words it keeps the overcharged intake from upsetting the tail of the boat during shutdown..Correct?
YES YES YES
That's all it's about. That's all it's ever been about.
old

[Cs19]

YES YES YES
That's all it's about. That's all it's ever been about.
old
Whats wrong with a pop off valve like everyone else uses?

[cyclone]

Whats wrong with a pop off valve like everyone else uses?
the duct costs 1900 dollars less?

[Old Guy]

Nothing happened. You seem like your about to blow a gasket though. :confused:
First of all, I didnt start the nozzle thread.. I'm personally not too interested in the adjustable nozzle, got other things on my plate that Im excited about, but I'd like to see someone develop one. That would be a fun project to take on. Id be interested in helping out in anyway possible if someone wanted to take a shot at it.
Next..Im with you Old guy...I'm so burnt on talking about the turbo motor I cant even tell you. If its 2000 hp thats great, Im not asking him to prove anything, he decided to try and prove it.
Ive said it before and Ill say it again, I only question the actual performance of the boat, and now that you guys are saying it makes 1600 horsepower, Im really questioning the performance. Problem is everytime we get to talkin' about the performance of the boat we end up talking about efi and injectors and fuel curves and stuff.:(
Do those socket head cap screws create any drag?
LOL no blown gaskets here. I know YOU didn't start this thread. YOU participated....good enough for me.
Think about it...hp = $$$. A friend of mine has set world records over and over again.....not because of $$$$$. He used his brain instead. As a result, nobody has been able to better his records. http://redlinemotorsports.net/
The point here is that there are very many questions about jet pumps that don't seem to get asked. The concept is simple. For example, an outboard motor does not require a "tail bearing"......why does a jet pump need a shaft running clear through the pump?
If speed = mass X velocity, why is a 3" nozzle necessary. Can't you get the velocity without the losses associated with squeezing the flow down to 3"?
The irrigation pump was connected to a pipe....think about it.
old

[MikeF]

Did you guys ever put countersunk hardware on that thing?
I was thinking that when the water hit the first one (capscrew).....it would make a big enough of a hole that it (the water) would not touch the rest of them. :)

[Old Guy]

I was thinking that when the water hit the first one (capscrew).....it would make a big enough of a hole that it (the water) would not touch the rest of them. :)
You're probably right. I think maybe Mark figures he can spare the extra hp it takes to drag the screw heads through the water.
If you want to think about something really important, think about bowl pressure. In order to make a boat go, you need to move water. The pressure in the bowl comes from resistance to flow. Because our pump configuration requires the water to change direction as it moves through a path of changing displacement, we invest a lot of hp that is really not very productive. We need flow, not pressure.
Don't ask me how to get flow without pressure. It takes hp to move water from point A to point B. It takes hp to build pressure. These are 2 distinctly different and separate concepts.
We accept the bowl pressure as part of what you get with a jet pump. I'm just pointing out what it is that makes it inefficient. If you can get the same nozzle velocity without the huge bowl pressure, you are gonna make the boat go faster using less hp.
Think about it.
old

[Unchained]

The old picture of the duct was taken before I countersunk the screws and went to flatheads AND THANKS FOR POINTING THAT OUT. :D
If ANYONE is interested in the duct I WILL SEND IT TO YOU FREE OF CHARGE to try. I will send it to you even if you just want to look at it. If someone wants to keep it and try it for a season, fine, they're easy to make. I think I have about $ 90 into it and a couple hours of time. I would love to have someone more analytical than me use it. Especially someone who races regularly.
I intended to try some slight changes in angle but never got around to it. The flat bottom of the duct is a large planing surface and could add lift to a heavy boat. That is an area that I feel some gains could be had. I just have it mounted parallell to the keel.
One thing is for sure, the back of your boat will not hop on shutdown no matter how much shoe you put to it. It can't.
It bolts on with the existing intake bolts although I inlarged the front two to 5/16 and used flathead allen bolts for all eight bolts I used. I made a stainless backer that the bolts thread into so I didn't have to hold the nuts on the top side. It installs real easy with a T handle allen wrench.
I'm sure it causes some drag but probably a small fraction of what an outdrive or a V drive rudder causes. The material is 3/16 stainless sharpened to a knife edge.
Back to the adjustable nozzle.
I searched through many old Hot Boat mag issues and never did find the one I wanted but I did find a picture of someones prototype on page 23 of the Sept 1994 issue. It was in the jet tech column so I bet Greg Shoemaker would know something about it.

[Duane HTP]

Unchained, Could I take you up on that offer? I'd like to bolt it on one of the Stealth's here that we've been racing and see how it reacts. I have data on the boat and could run data with the duct installed to determine what it does or doesn't do. This boat has ecxactly the same bottom as yours, so it would be a very even compairison. I'd also like to run it on the purple Cheyenne.
I would appreciate the chance to evaluate it.
Thanks, Duane HTP

[HighRoller]

Brian mentioned my interest in this subject and I first came up with the idea around 10 years ago. But, as Cyclone said, I too could not wrap my head around how to make a variable diameter nozzle. The application I have in mind is for recreational boat, one that provides a substantial nozzle opening at low speeds for acceleration or skiing and can be adjusted down to wherever you feel your maximum speed will be attained.
However, after a little thought I reasoned that the biggest gain to be had from this setup would be GPH of fuel use at cruising RPM. With a stock or near stock boat, you have to turn 3000-3500RPM to achieve 30-35mph because the impeller and nozzle diameter are tuned for low end acceleration. This can be cured with a bigger impeller or smaller nozzle, but your low end pop will suffer, especially in a 3500 lb boat loaded with people. I know cruise RPM is not a big factor for you racing guys, but when you go from Laughlin to Topock or Havasu and back in a day it's a big deal!
My solution was a nozzle piece that bolted on like the place diverter stuff and had a setup that worked like the turkey feathers on a fighter jet. The real challenge is not changing the shape of the water while shrinking the nozzle, otherwise you could just have a couple flaps that clamped down over the nozzle opening. The other dilemma is how to have small scale hydraulic actuators that were small enough to not clutter up the nozzle yet powerful enough to clamp down on a large stream of water. This goes hand in hand with the design of the "feathers", which must be shaped so that the nozzle shape remains constant and does not leak when expanded or contracted.
I've seen the marine jet tech version, and while it seems effective it's a little bit ghetto. I'm sure it works well on aluminum fishing rigs, but I'm not sure about hi-po stuff.

[Old Guy]

My solution was a nozzle piece that bolted on like the place diverter stuff and had a setup that worked like the turkey feathers on a fighter jet. The real challenge is not changing the shape of the water while shrinking the nozzle, otherwise you could just have a couple flaps that clamped down over the nozzle opening. The other dilemma is how to have small scale hydraulic actuators that were small enough to not clutter up the nozzle yet powerful enough to clamp down on a large stream of water. This goes hand in hand with the design of the "feathers", which must be shaped so that the nozzle shape remains constant and does not leak when expanded or contracted.
I've seen the marine jet tech version, and while it seems effective it's a little bit ghetto. I'm sure it works well on aluminum fishing rigs, but I'm not sure about hi-po stuff.
I'm quite sure I can make one that will work reliably on any split bowl jet pump. The question for me is still the same........is it worth making. I can come up with some logic that indicates that it's not gonna make a big difference.
The question is:
Can you maintain the same speed with less rpm by using a smaller nozzle?
There can be a lot of enhancement to the question, but let's just start with an answer to the basic question.

[Unchained]

Unchained, Could I take you up on that offer? I'd like to bolt it on one of the Stealth's here that we've been racing and see how it reacts. I have data on the boat and could run data with the duct installed to determine what it does or doesn't do. This boat has exactly the same bottom as yours, so it would be a very even compairison. I'd also like to run it on the purple Cheyenne.
I would appreciate the chance to evaluate it.
Thanks, Duane HTP
Sure thing Duane, I'll remove it and make a print of it before I send it out so I'll be a couple days.
That way I can make another if you keep it for next season.
If someone respected in the industry like yourself could provide data and feedback that would be huge.
I'll still extend the offer to anyone else too.
I can whip one up in a week or so.

[steelcomp]

From a functional standpoint, I think the duct is a great idea, but from a racing standpoint, I can't get past the added drag.

[Unchained]

From a functional standpoint, I think the duct is a great idea, but from a racing standpoint, I can't get past the added drag.
Well you won't like a V drive then.
There's lots of hardware dragging in the water.
Actually the sides of the duct are right tight up against the fins on the intake so the water is broke there somewhat already. The bottom of it is 8.25 wide and .187 thick and is sharpened to a knife edge so the main source of drag is around 1.5 sq. in.
Here's what you're looking at for drag,
http://www.***boat.com/image_center/data/520/220keel1.jpg

[steelcomp]

Well you won't like a V drive then.
There's lots of hardware dragging in the water.
Actually the sides of the duct are right tight up against the fins on the intake so the water is broke there somewhat already. The bottom of it is 8.25 wide and .187 thick and is sharpened to a knife edge so the main source of drag is around 1.5 sq. in.
Here's what you're looking at for drag,
http://www.***boat.com/image_center/data/520/220keel1.jpgWell, it's not a v-drive, so that's a useless comparison. A useful comparison would be with it, vs. without it. It's because jets are so clean underneath that they are very sensitive to drag. The flanges at the top are drag, the sides (inside and out) are drag, the bottom (inside and out) is drag, the transition from the side of the fin to the duct is drag...there's a ton of drag there. If you go to the races, you'd see that the bracket guys tune their ET's by raising and lowering their speedo pick-ups. Not much drag there, you'd think, but that small of an area makes a big enough difference. Knowing that, made me look at the bottom of my boat in a whole new light.
Like I said, I'm not questioning it's effectiveness as a safety device, and really not intending to criticize, just commenting on an observation.

[Unchained]

..there's a ton of drag there..
A whole ton ? That's more than the boat weighs.

[Old Guy]

Mark says it provides quite a bit of lift. Do you suppose that the loss of wetted surface and it's associated drag would offset the additional drag of tunnel?
I think if you're going to analyze, you should consider ALL the factors present......don't you?
old

[steelcomp]

Mark says it provides quite a bit of lift. Do you suppose that the loss of wetted surface and it's associated drag would offset the additional drag of tunnel?
I think if you're going to analyze, you should consider ALL the factors present......don't you?
oldMark says a lot of things that get questioned. There are other effective ways of getting lift with far less drag, so to answer your question, I already considered that, and yes, in my mind, without a doubt.
I think a lot more about what I'm saying than you give credit for, but I appreciate your suggestion, condescending as it was.

[bottom feeder]

Old guy,
I have several working prototypes for adjustable on the fly nozzles. Out of the four not one of them will maintain the same MPH at a decreased RPM. This my be one of them laws that get in the way? As the dia is decreased the pressure rises so does the required power to generate the pressure or something of that sort.

[Duane HTP]

From a functional standpoint, I think the duct is a great idea, but from a racing standpoint, I can't get past the added drag.
That's equivalent of saying a pop-off may be a good safety device, but I can't get past the weight it would add to a race boat.
This may be a usable safety device. (It may not). But let's give it the benifit of the doubt until it is tested. I've seen it work. Now I'm going to get a chance to see how well. I find some of the physics of this thing interesting.

[bottom feeder]

Mark says a lot of things that get questioned. There are other effective ways of getting lift with far less drag, so to answer your question, I already considered that, and yes, in my mind, without a doubt.
I think a lot more about what I'm saying than you give credit for, but I appreciate your suggestion, condescending as it was.
Do you think the pop off valve is more reliable? Yes it is more proven as I only know of a couple of people running the duct And three companys that have made pop off valves. Yes it adds drag so does the pop off.

[steelcomp]

That's equivalent of saying a pop-off may be a good safety device, but I can't get past the weight it would add to a race boat.
This may be a usable safety device. (It may not). But let's give it the benifit of the doubt until it is tested. I've seen it work. Now I'm going to get a chance to see how well. I find some of the physics of this thing interesting.That's BS Duane. A popoff dosen't effect enough performance with it's added weight to even be measurable, and you know it. If dropping or raising the speedo pick-up can alter a boat's ET, what do you think that duct hanging under the boat'll do? Sounds like you're going to have an opportunity to find out. I don't know why everyone's getting all butthurt about this...it's nothing personal, just a fact of physics. You say let's give it the benefit of the doubt...I never doubted it's effectiveness as a safety device, and have stated that twice, now. My comments are referring to it as a racing device, where there are other products that have NO parasitic drag that accomplish the same thing. There may be some out there who would accept the tradeoff for the fact that it requires no driver input, and seems to work automatically. Cool. Maybe you'll prove that it's negative effect AFA drag is concerned is negligable, and it will serve as an effecetive racing device as well. Bitchen. Untill then, by my observations, from my understanding of how drag effects performance, I'll maintain that the added drag isn't worth it in a racing application. IT'S NOTHING PERSONAL!!!

[steelcomp]

Do you think the pop off valve is more reliable? Yes it is more proven as I only know of a couple of people running the duct And three companys that have made pop off valves. Yes it adds drag so does the pop off.I think the popoff has come a long way, and there is definately a benefit to the duct in that it is automatic in it's function.
How does a pop-off add the kind of drag that can be associated with the duct?

[Infomaniac]

A whole ton ? That's more than the boat weighs.
Thats OK unless your boat has less than a ton of boyancy :D
Because thrust is what has to overcome drag. :rolleyes:

[bottom feeder]

I think the popoff has come a long way, and there is definately a benefit to the duct in that it is automatic in it's function.
How does a pop-off add the kind of drag that can be associated with the duct?
Not near the drag. It does introduce added drag and terbulant flow on the hand hole area and the slight weight diferance. Also heard they are not exactly dead reliable.

[Old Guy]

Old guy,
I have several working prototypes for adjustable on the fly nozzles. Out of the four not one of them will maintain the same MPH at a decreased RPM. This my be one of them laws that get in the way? As the dia is decreased the pressure rises so does the required power to generate the pressure or something of that sort.
Thanks for the input. It has always seemed to me that by decreasing the nozzle diameter, you could increase the velocity of the flow through it, BUT only if you added some power to overcome the increased resistance of the smaller hole.
I really think the answer is in lowering the "drag" in the pump itself. I think a focus on maintaining direction on the water would help a lot. If you follow the flow profile of the water going through a pump, you can see how much redirection is taking place. So you say "So what?".
Do the math.....you can do enough in your head (well some of us can) to see what kind of power it taking.
Let's take a big motor that's making 1200 hp running flat out. Lot of water going through the pump huh. What's a lot of water? If he's turning the pump 6000+ rpm, he's moving 5000+ gpm @ 8+ lbs/gallon = 40,000 lbs per minute going through the pump.
What I'm saying here is that changing the direction (other than straight back) of that much water just to get it through the pump is wasting a huge amount of hp.
Of all the things to monitor with a DA set-up, I would think nozzle velocity would be near the top of the list. Engine rpm, intake pressure, and bowl pressure are important, but if these are compared to nozzle velocity you would have all the necessary tools to set about improving pump performance.
old

[Duane HTP]

Steel, I completely understand the added drag equation. I'm not looking at this thing strictly for the shut down aspect, I'm really interested in this thing because of the speed that Mark picked up when he got this thing working. I'm looking for some other benifits here. I think there might be some. That's why I'm going to play with it. Hey, I've got all kinds of prototypes of jet parts I've built, that DIDN'T work. I'm not one of the tunnel visioneers, I'm always looking for new and better things for jets.

[steelcomp]

Not near the drag. It does introduce added drag and terbulant flow on the hand hole area and the slight weight diferance. Also heard they are not exactly dead reliable.I don't think the turbulence is any different than a stock hand hole cover. The reliability seems to have been improved, but yes, they've been known to be unreliable. Some makes are better than others. There was also a problem with them breaking the ears off the suction piece, but MPD came up with a trick girdle that has eliminated that problem. The added weight is always a factor. The system probably weighs, I would guess, in the neighborhood of 10-15 lbs.
The duct is definately something that has interesting capabilities. I'm sure it's a long way from optimal in it;s current configuration, and may well be the hot ticket with some good r&d. If it truely is worth it's design, I can see it being integrated into an intake. Without having then top mounting flanges, and the added sides (using the fins as the actual sides of teh duct) you'd eliminate about 60% or more of the added drag, basically just adding the bottom of the box into the picture. I can see playing with things like the distance from the bottom of tehe duct to the keel or shoe, and the fore-aft placement in reference to the intake opening. Even the length might be critical. Lot's of possibilities.

[Old Guy]

A little more help with the math? That's more than 650 pounds of water PER SECOND following a crooked path through the jet pump
old

[steelcomp]

Steel, I completely understand the added drag equation. I'm not looking at this thing strictly for the shut down aspect, I'm really interested in this thing because of the speed that Mark picked up when he got this thing working. I'm looking for some other benifits here. I think there might be some. That's why I'm going to play with it. Hey, I've got all kinds of prototypes of jet parts I've built, that DIDN'T work. I'm not one of the tunnel visioneers, I'm always looking for new and better things for jets.I know, Duane, and I'm hoping for some good feedback with your testing. My guess is that if Mark takes this off his boat, all else being equal- meaning he can achieve the same running attitude- the boat will pick up mph and acceleration. Other things may suffer like some stability and shutdown behavior, which can be huge to someone not looking for that last n'th of performance, but I believe that performance will improve.

[steelcomp]

A little more help with the math? That's more than 650 pounds of water PER SECOND following a crooked path through the jet pump
oldOld, with the water going through any kind of impeller, isn't it going to be basically spinning? Aren't there forces that have to be overcome to get the water moving in a linear direction again, after the impeller? I see it as a big flywheel of water that you're trying to shove through a pipe...something has to straighten the water out and get it flowing again...IE the vanes in the bowl. Is this not correct? The water has to exit the pump in as linear a fashion as possible, and to do that it seems it has to change direction after the impeller. Of course, I'm still thinking on the basis of the existing pump design.

[cyclone]

What would you use to measure nozzle velocity? i wouldnt want to stick a pitot tube at the end of the nozzle.

[blue wonder]

hey unchained...what was the best mph you ran before and after the addition of the plate?

[Old Guy]

What would you use to measure nozzle velocity? i wouldnt want to stick a pitot tube at the end of the nozzle.
Why not? After you finish with the R&D, you take them (I would use several) out. I'm talking about DA as a development tool, not a performance monitoring tool.
I used to design and build production machinery. Sometimes we would design and build a machine for the sole purpose of learning important answers. Sometimes it's way more practical to build something small to get answers than it is to shut down a $2M production line for tinkering.

[MikeF]

What would you use to measure nozzle velocity? i wouldnt want to stick a pitot tube at the end of the nozzle.
Might be able to design a type of magnetic pickup (like a crank trigger) w/a paddlewheel type reluctor slightly in the path of the jetstream (would likely need some real good bearings). Reluctor would spin, leading to a RPM signal that could then be used as info for adjustments.:idea:

[cyclone]

Why not? After you finish with the R&D, you take them (I would use several) out. I'm talking about DA as a development tool, not a performance monitoring tool.
I used to design and build production machinery. Sometimes we would design and build a machine for the sole purpose of learning important answers. Sometimes it's way more practical to build something small to get answers than it is to shut down a $2M production line for tinkering.
I thought he pitot tube might break from the force of the water. no? never used one before so im not sure. i guess if its strong enough to hang off the transom then its strong enough to hang off the nozzle.

[cyclone]

how about we get back to the nozzle question and start a new thread on the duct thing?
old guy says he can build it.
bottom feeder says he has already but they didn't work.
dana says they've got one already built
i can't build it but think there's definately merit in having an adjustable nozzle whether you are racing or not in your jet boat. i dont believe the nozzle should be a "one sized fits all" deal.
so who's gonna step up and do this? I'll be a guinea pig for testing it on my boat.

[bottom feeder]

cyclone
Hey I never said it did not work. What I was looking for and what you are looking for may be entirely diferant things. Not right or wrong. The action of the nozzle just led me to other issues. If someone wants to pursue it just say so. Maby I can help save some time maby not?

[Old Guy]

how about we get back to the nozzle question and start a new thread on the duct thing?
old guy says he can build it.
bottom feeder says he has already but they didn't work.
dana says they've got one already built
i can't build it but think there's definately merit in having an adjustable nozzle whether you are racing or not in your jet boat. i dont believe the nozzle should be a "one sized fits all" deal.
so who's gonna step up and do this? I'll be a guinea pig for testing it on my boat.
Unless someone can provide evidence that the concept is sound, I am not about to put 6 months or so into building one.
For example, if someone could show me that a 3.000" nozzle would make a boat faster than a 3.063" nozzle with the same hp however the hole shot with the 3.000" nozzle was real bad, I would start to get interested.
Take any boat with at least 500 hp and tell me what diameter nozzle will make it go the fastest at the end of a one mile run, then tell me what size nozzle provides the very best hole shot (forget about top speed). Now I have something to work with. Without that (very basic) information, I have nothing. Without that kind of info I don't build anything.
old

[flat broke]

Unless someone can provide evidence that the concept is sound, I am not about to put 6 months or so into building one.
For example, if someone could show me that a 3.000" nozzle would make a boat faster than a 3.063" nozzle with the same hp however the hole shot with the 3.000" nozzle was real bad, I would start to get interested.
Take any boat with at least 500 hp and tell me what diameter nozzle will make it go the fastest at the end of a one mile run, then tell me what size nozzle provides the very best hole shot (forget about top speed). Now I have something to work with. Without that (very basic) information, I have nothing. Without that kind of info I don't build anything.
old
I'd be willing to guess that BP, CS, and maybe Mike, all have data on the change in nozzle diameter with 1/8th mile and 1/4 mile.
Chris

[Cs19]

:sqeyes:

[Infomaniac]

I had a really simple design in mind but since the nozzle has to start out large and go smaller. That killed it. :mad: Would be real easy to have a nozzle grow larger to maintain a speciic bowl pressure. But I'm not sure what that would do for veocity.

[bp]

The point here is that there are very many questions about jet pumps that don't seem to get asked. The concept is simple.
For example, an outboard motor does not require a "tail bearing"......
pumps don't "require" a "tail bearing", so what is the point?
why does a jet pump need a shaft running clear through the pump?
that might be a better question for the v-drive board; "why do you have a shaft running through the bottom of your boat???
If speed = mass X velocity,
speed does not equal mass x velocity.
why is a 3" nozzle necessary.
it's not.
Can't you get the velocity without the losses associated with squeezing the flow down to 3"?
yes, you can (well, somebody that's actually running a boat can).
The irrigation pump was connected to a pipe....think about it.
old
ok. now what? a 1200mw westinghouse reactor coolant pump is connected to a pipe too, and is exactly the same type pump as a jetboat uses, except a LOT larger, with an 80,000 hp motor on top of it, vertically installed, and they run continuously for 20 months. you can call it an irrigation pump, i'll call it a nuclear reactor coolant pump. charging pumps, heat removal pumps, condensate pumps, booster pumps, positive displacement pumps, feedwater pumps, circulating pumps are ALL connected to pipes...

[steelcomp]

with an 80,000 hp motor on top of itIs that measured or lake hp? :jawdrop: :D (sorry...couldn't resist)

[Placecraft Dragstar]

pumps don't "require" a "tail bearing", so what is the point?
that might be a better question for the v-drive board; "why do you have a shaft running through the bottom of your boat???
speed does not equal mass x velocity.
it's not.
yes, you can (well, somebody that's actually running a boat can).
ok. now what? a 1200mw westinghouse reactor coolant pump is connected to a pipe too, and is exactly the same type pump as a jetboat uses, except a LOT larger, with an 80,000 hp motor on top of it, vertically installed, and they run continuously for 20 months. you can call it an irrigation pump, i'll call it a nuclear reactor coolant pump. charging pumps, heat removal pumps, condensate pumps, booster pumps, positive displacement pumps, feedwater pumps, circulating pumps are ALL connected to pipes...
THIS IS GETTING GOOD NOW, ALOT OF INFO HERE:idea: :eat:

[Old Guy]

pumps don't "require" a "tail bearing", so what is the point?
that might be a better question for the v-drive board; "why do you have a shaft running through the bottom of your boat???
speed does not equal mass x velocity.
it's not.
yes, you can (well, somebody that's actually running a boat can).
ok. now what? a 1200mw westinghouse reactor coolant pump is connected to a pipe too, and is exactly the same type pump as a jetboat uses, except a LOT larger, with an 80,000 hp motor on top of it, vertically installed, and they run continuously for 20 months. you can call it an irrigation pump, i'll call it a nuclear reactor coolant pump. charging pumps, heat removal pumps, condensate pumps, booster pumps, positive displacement pumps, feedwater pumps, circulating pumps are ALL connected to pipes...
WOW!!!!!!!!
I was hoping to stimulate some new, creative, intelligent thought so as to improve the efficiency of a jet pump. I never dreamed we could get so lucky. I am amazed that a person with your obviously incredible intellect would be willing to take the time to help us out here. Your depth of knowledge on the subject must be at least equal to or maybe even greater than that of anyone else on the planet. The way you were able to spot inaccuracies in what I posted and point each one out and even provide a quick counter statement.......amazing!!!!!!
I am obviously a rambling old fool, and should not be taken seriously. You have made that very clear.
So now Mr or Ms bp, you have the floor. Don't hold back. We all look forward to great new enlightenment.
Let's hear it!!!!!
old

[steelcomp]

WOW!!!!!!!!
I was hoping to stimulate some new, creative, intelligent thought so as to improve the efficiency of a jet pump. I never dreamed we could get so lucky. I am amazed that a person with your obviously incredible intellect would be willing to take the time to help us out here. Your depth of knowledge on the subject must be at least equal to or maybe even greater than that of anyone else on the planet. The way you were able to spot inaccuracies in what I posted and point each one out and even provide a quick counter statement.......amazing!!!!!!
I am obviously a rambling old fool, and should not be taken seriously. You have made that very clear.
So now Mr or Ms bp, you have the floor. Don't hold back. We all look forward to great new enlightenment.
Let's hear it!!!!!
oldWhy don't you just constructively counter his points and comments instead of the sarcastic diversion. You've done plenty of rambling on this thread but really haven't said anything. I asked you a direct question regarding your comments on not having to bend the water in a pump. You ignored that.
Personally, I think your attitude sucks.
BTW...you'd be surprised at how much you could be "enlightened" by bp.

[oldselmn8tr]

New guy here so might as well jump right in. Why the hell is every one so cynical? Yes you can do things on your own but you would think that with the combined intelligence of so many people that you could steepen the learning and creative curve greatly. If you have a counter point present the argument intelligently not like an ass! When I first got my jet I wondered why there was no real info out there on how to blueprint a pump. The more I read the more I realize the attitude of these so called experts is the reason why. Is everyone afraid there secrets are going to get out to the genral public and ther actualy going to have to develop something new? How old is the basic design of a jet pump? No one can improve this thing? Hell Old Guy is trying to help,someone volunteer some of there ever so secretive info instead of giving him shit at every turn.We all might benefit, if not us at least it might keep the jet boat world from certain eventual death. Unfortunately I don't have enough experiance to donate squat, but I know that everything can be improved or changed to make work better it's been proven time and again.

[Old Guy]

Old, with the water going through any kind of impeller, isn't it going to be basically spinning? Aren't there forces that have to be overcome to get the water moving in a linear direction again, after the impeller? I see it as a big flywheel of water that you're trying to shove through a pipe...something has to straighten the water out and get it flowing again...IE the vanes in the bowl. Is this not correct? The water has to exit the pump in as linear a fashion as possible, and to do that it seems it has to change direction after the impeller. Of course, I'm still thinking on the basis of the existing pump design.
Sorry Steel, I failed to realize that you had asked a question. I thought you were just stating an obvious fact. The answer to your question is yes. The water MUST change direction to get all the way through the pump. I was hoping that it might occur to somebody that there is a lot of stuff between the impeller and the nozzle. While outboards and vee drives don't use a mixed flow device to move water, they also don't need support downstream of the water mover. So the next question should be....how much of the stuff (shaft, bowl vanes, etc.) to the rear of the impeller represent the very best way to do it.
old

[jweeks123]

why not just switch to an axial jet. much less bowl pressure. much less direction change. what's your take on that old guy
jw

[steelcomp]

Sorry Steel, I failed to realize that you had asked a question. I thought you were just stating an obvious fact. The answer to your question is yes. The water MUST change direction to get all the way through the pump. I was hoping that it might occur to somebody that there is a lot of stuff between the impeller and the nozzle. While outboards and vee drives don't use a mixed flow device to move water, they also don't need support downstream of the water mover. So the next question should be....how much of the stuff (shaft, bowl vanes, etc.) to the rear of the impeller represent the very best way to do it.
oldOK...on topic...if you remove the vanes, bowl, shaft, etc, you end up with a prop, not an impeller, is that not correct? If I remember correctly, the whole idea of a jet was that it eliminated a dangerous prop under the boat. In order to do that, you had to bring the water to the propulsion device, and somehow accelerate it to create thrust. This required a change of direction in the water, some sort of pressurization or acceleration of the water, and a release mechanism.
I guess I'm just not following all of your hints as to what could so drastically change that would do the same thing, that someone else a lot smarter than most of us here hasn't already thought of. Effeciency is a tricky opponent, because it always takes something to make something...in this case, HP to make thrust, in a safe manner other than a prop.
OH...and sorry for jumping ugly on you, Old. My bad.

[Old Guy]

why not just switch to an axial jet. much less bowl pressure. much less direction change. what's your take on that old guy
jw
I think it's been pretty well proven that in order to get the necessary velocity, without cavitation, you need a mixed flow impeller. I'm accepting the word of others here.
To be honest, I've read quite a bit on the subject and I have never seen data that proves you can't do it with an axial flow impeller.
If I was 30-40 years younger I would really like to do some REAL R&D on this stuff. I'm not, so....oh well. Maybe somebody else will.
old

[oldselmn8tr]

He didn't say get rid off it, he said is it the best way to do it. And as for safety I don't think that is why most people with fast jets have a jet.:D

[Old Guy]

OK...on topic...if you remove the vanes, bowl, shaft, etc, you end up with a prop, not an )impeller, is that not correct? If I remember correctly, the whole idea of a jet was that it eliminated a dangerous prop under the boat. In order to do that, you had to bring the water to the propulsion device, and somehow accelerate it to create thrust. This required a change of direction in the water, some sort of pressurization or acceleration of the water, and a release mechanism.
I guess I'm just not following all of your hints as to what could so drastically change that would do the same thing, that someone else a lot smarter than most of us here hasn't already thought of. Effeciency is a tricky opponent, because it always takes something to make something...in this case, HP to make thrust, in a safe manner other than a prop.
OH...and sorry for jumping ugly on you, Old. My bad.
Sometimes I forget (hell, I'm old), I spent most of my life designing and/or re-working production machinery. It was all about $$$$, lots of $$$$$. Many times we would drop $10K - $20K to develop something that returned many times the R&D cost, often in a matter of a few months. In the world of R&D, nothing is sacred. Sometimes you start with a blank sheet of paper and add, one piece at a time, (but only if it was exactly the best piece), the stuff necessary to meet the objective. Oh yeah, when we talked about "how long will it take?", we looked at our watches.
Sometimes, I'm not very patient with others. One of my many failings.
I have a complete machine shop. I can make pretty much anything i want to make. Trouble is, I'm old and gettin older.I need to be selective. Reality is lookin me straight in the eye.
old

[Cs19]

I am obviously a rambling old fool, and should not be taken seriously
Whats your deal old guy? Your just another member of the message board here, why should we think anything special of you? To be perfectly honest your posts have not been all that impressive up until this point but yet you threaten us by saying you will leave the board if we dont kiss your ass.:confused: My view on that is... Dont let the door hit you in the ass on the way out.
Between the duct and your unrealistic pop off design from a few years back you dont have anyone convinced you have a freaking clue. If you struck the people here as someone worth working with maybe you might get something accomplished and make jetboats work better.
Im all for new and different ideas, Ive got dozens of ideas in my head that have been shot down by who I consider the best but I still want to try them, dont think we are close minded or not open to trying new or off the wall ideas cause that is not true.

[Cs19]

There you go..Up until this point nobody knew anything about you but youve been acting like your Alan Johnson. Sounds like you have a nice resume.
Sometimes I forget (hell, I'm old), I spent most of my life designing and/or re-working production machinery. It was all about $$$$, lots of $$$$$. Many times we would drop $10K - $20K to develop something that returned many times the R&D cost, often in a matter of a few months. In the world of R&D, nothing is sacred. Sometimes you start with a blank sheet of paper and add, one piece at a time, (but only if it was exactly the best piece), the stuff necessary to meet the objective. Oh yeah, when we talked about "how long will it take?", we looked at our watches.
Sometimes, I'm not very patient with others. One of my many failings.
I have a complete machine shop. I can make pretty much anything i want to make. Trouble is, I'm old and gettin older.I need to be selective. Reality is lookin me straight in the eye.
old

[Old Guy]

There you go..Up until this point nobody knew anything about you but youve been acting like your Alan Johnson. Sounds like you have a nice resume.
Well dude, if it really matters. I don't remember making any kind of threats about leaving...but I guess if that's the way you see it. I guess that's gotta be the way it is.
You want to know who I am? I can't imagine why. I've never seen that asked of anybody else.
OK, here we go. I'm 70 years old. I'm retired. I spent about 45 years in manufacturing. I managed 3 business (one at a time). I've saved 2 business from bankruptcy. I have effectively worked as, business owner, manager, engineer, maintenance man, salesman, accountant, cost analyst, inventor, to mention a few. Inventor?...damn right, my name is on at least 15 patents at the US Patent Office.
I can do CAD design work with AutoCAD 2000.
I have NEVER suggested that anybody should kiss my ass.
Now tell me why I should kiss your ass dude.
old

[Cs19]

.Now tell me why I should kiss your ass dude.
No reason at all.
Youve been taking a beating here just trying to help ya out a little, it appears you have been looking for the respect you think you deserve..

[Old Guy]

No reason at all.
Youve been taking a beating here just trying to help ya out a little, it appears you have been looking for the respect you think you deserve..
Respect is something you earn....or not
I'm not asking for a damn thing
I've been trying to contribute something, or stimulate others to contribute something.
You got something to contribute?
I'm way too old for this BS dude
Fish or cut bait!
old

[Clockstart]

I think it's been pretty well proven that in order to get the necessary velocity, without cavitation, you need a mixed flow impeller. I'm accepting the word of others here.
To be honest, I've read quite a bit on the subject and I have never seen data that proves you can't do it with an axial flow impeller.
If I was 30-40 years younger I would really like to do some REAL R&D on this stuff. I'm not, so....oh well. Maybe somebody else will.
old
This seems to sugest that the designers of the current jets didn't know what they were doing. :confused:

[Cs19]

blah...:rolleyes:
Your not gettin any younger here, make something happen in the world of jet boats already. Best of luck to you and whoever is involved.
Chris

[Old Guy]

[QUOTE=cs19;2315316]blah...:rolleyes:
Your not gettin any younger here, make something happen in the world of jet boats already. Best of luck to you and whoever is involved.
Chris[/QUOTE
You're not gettin it dude. This is about nozzle diameter. Do you have something worthwhile to add to the discussion?
old

[Old Guy]

This seems to sugest that the designers of the current jets didn't know what they were doing. :confused:
Damn right sonny. The guy who invented the Model A didn't have much goin for him either did he. Think about what you are saying!!!
old

[Cs19]

[QUOTE=cs19;2315316]blah...:rolleyes:
Your not gettin any younger here, make something happen in the world of jet boats already. Best of luck to you and whoever is involved.
Chris[/QUOTE
You're not gettin it dude. This is about nozzle diameter. Do you have something worthwhile to add to the discussion?
old
Read the post oldguy!
No i dont have anything to add. Im wishing you luck here as Im all done here.
Best of luck!

[Old Guy]

[QUOTE=Old Guy;2315325]
Read the post oldguy!
No i dont have anything to add. Im wishing you luck here as Im all done here.
Best of luck!
That's it???
You got nuthin to offer. Just come in rip somebody?
You are really somethin special aren't you?
Good luck on the respect thing dude
old

[Old Guy]

OK bp, you going to offer something useful?
I'm supposed to be thrilled about what we can learn from you .
Teach dude!!
old

[Clockstart]

They did 30 years ago. But what has changed in the basic design since then.
Legend and Aggressor are new on the scene in the last 10 yrs and both have changed the impeller & bowl designs. Dominator/ AmTurbine has new impeller & bowl designs. What have the Canadians done? Welded impellers and $5000 bowls & suction pieces. BTW, one of your winningest racers doesn't run the $5K stuff, he just runs a Dom race bowl. So why is the current crop of parts so bad?

[Clockstart]

Never said they were bad...just old.So OLD is a negative thing? :D

[cyclone]

I'd be willing to guess that BP, CS, and maybe Mike, all have data on the change in nozzle diameter with 1/8th mile and 1/4 mile.
Chris
Ok i'll try a bit here. first let me qualify or not qualify my post by saying that i'm not a professional racer. my program is not the most scientific. there are other way more qualified guys on the board that have this sort of info that likely aren't willing to share it. anyway, here goes. bear in mind that i'm nowhere near my log book and am posting this from memory:
after going out early in the finals of the october race at lake ming i took the opportunity to make some safety passes during lulls in the program to change hardware on my boat and evaluate the results. I made three back to back runs down the track changing only the nozzle inserts in the pump.
the first pass i had a 3.060 insert in the pump and the boat left the line the hardest, accelerated hard to the 1/8 mile mark and then stopped accelerating. ran about 110 mph out the back door.
2nd pass was with a 3.090 insert and the boat didnt leave the line quite as hard, got to the 1/8 mile mark about a tenth of a second slower but ran a better 1/4 mile ET at about 113 mph.
3rd pass with a 3.125 nozzle holeshot sucked, mid et sucked, but 1/4 mile et improved by another tenth of a second and the boat ran about 116 mph.
i was not using a launch controller during the passes so there's always the chance that the boat didn't leave the line exactly the same. Take what you want from this but it appeared to me that squeezing the nozzle improved the holeshot but hurt the top end speed.
when i get a chance i'll try to post the timeslips so that you guys have the exact numbers.
hope this helps.

[Duane HTP]

Cyclone, Interesting. Your boat reacts to nozzle size change exactly like our boats do. That's why I asked the question earlier in this thread, "Are you positive the nozzle needs to go from large to small?"
When I was playing with my deal, I was going from small to large about 1/2 track. It almost felt like shifting gears. Of course back in those days, we had no means to record what we were really doing, and we were running under a flag system rather than a clock system, so there were NO time slips.

[sleekcrafter]

I was told back in the day, they would pop the chokes out after the launch, and just finish the run without the choke. Seems that it was a bit costly, and eventually given up.:idea:

[Old Guy]

See how much better it gets when we discuss real experience situations with real numbers. This is information that is needed to even evaluate concepts.
I don't need time slips. There are so many variables that the experience that some of you have is probably enough to get started. I need to know a range of size. I expect that the bowl pressure/nozzle dia. relationship is important. I don't know how important. For example a 1500 hp motor producing 500# bowl pressure and a 3.060" nozzle will see a very different hole shot than the same set-up with 500 hp and what ever bowl pressure develops. It's the analysis of this kind of info that determines what (if any) change in nozzle dia. would help the most. You guys have this info, I don't. I don't need the information, I just need to know what the end resulting interpretation is. At that point, if it looks like a variable size nozzle is a good idea, I'd like to build one.....or even just offer design suggestions to somebody else competent to build it.
At present I'm thinking of a design that would have a "feather" type orifice sort of like a jet fighter. The feathers would be made of stainless and firmly attached at the front end. They would move by flexing. The actuator would be a bladder. The bladder would be driven by a hydraulic system.
This is a crude description of a concept. I think it could be made in a way that the usual sand issues wouldn't be a problem.
I'm always open to any and all suggestions.
Right now, I need to go take care of a few things, be back later.
old

[bp]

OK bp, you going to offer something useful?
I'm supposed to be thrilled about what we can learn from you .
Teach dude!!
old
ask a question, i'll answer it. but if you post a statement as fact, that is clearly bullshit, i'll call it what it is. as far as your sarcastic, whiney assed posts, and confrontational nonsense, i have no time for that.
if you have a question, ask it. if you have a point to make, make it.

[bp]

Cyclone, Interesting. Your boat reacts to nozzle size change exactly like our boats do. That's why I asked the question earlier in this thread, "Are you positive the nozzle needs to go from large to small?"
When I was playing with my deal, I was going from small to large about 1/2 track. It almost felt like shifting gears. Of course back in those days, we had no means to record what we were really doing, and we were running under a flag system rather than a clock system, so there were NO time slips.
duane, do you remember what "small" diameter would have been, or "large"? i remember 6 years ago, dan nelson was playing with his movable shoe, sliding it forward at half track. he had data, but he didn't feel he had a real good sense about +/- with respect to performance.

[blue wonder]

OK bp, you going to offer something useful?
I'm supposed to be thrilled about what we can learn from you .
Teach dude!!
old
you sure talk a alot of shit for someone who doesn't even hold a time slip in his possesion...why are you talking shit to bp...just one question how many championships have you one?????....obviously someone who has one as many championships as he has probably knows what the hell he is doing!!!!...just my 2 cents:D

[bottom feeder]

you sure talk a alot of shit for someone who doesn't even hold a time slip in his possesion...why are you talking shit to bp...just one question how many championships have you one?????....obviously someone who has one as many championships as he has probably knows what the hell he is doing!!!!...just my 2 cents:D
I have never seen a time slip build a part to improve said time slip.
Their is no doubt about BP and is abilitys to have a winning combo.
And from here you look like the shit talker.

[Duane HTP]

BP, If remember right, we were going from a 3.050" to a 3.125" nozzle. It also seemed that the unit worked the best with the biggest impeller you could run with the particular engine. In other words, it worked better with a boat that had the power to pull an "A" impeller than it did with a boat that was running a "C" impeller.
Yeah, I was one of those guilty of shedding the small nozzle right after hole shot. We won the championship in Comp Jet in 1979 while doing it. We kept quite about it because it was a grey area as to being legal or not.

[steelcomp]

Oh no....no time slip....BFD
championships.....again BFD
This is a discussion about adjustable nozzles.....go puff your chest out at someone that really cares about your ego cause I sure as hell don't
Great attitude, there. Can't you express an opinion without the sarcasm and condescension? Are you that much better than the rest of us?
My God...I don't think I've ever heard so much BS in one thread.
AFA timeslips, you're forgetting that what wins on Sunday, sells on Monday. A HUGE percentage of the technology we have today in performance is directly from the efforts of guys on the race track, collecting those time slips.
I can tell you this, it's this attitude that seems to surround boating and boat racers (in general) that prevents it from getting anywhere in the real racing world. The technology's out there. People who really have the knowledge and ability just won't be bothered. This I know for a fact.

[bp]

BP, If remember right, we were going from a 3.050" to a 3.125" nozzle. It also seemed that the unit worked the best with the biggest impeller you could run with the particular engine. In other words, it worked better with a boat that had the power to pull an "A" impeller than it did with a boat that was running a "C" impeller.
Yeah, I was one of those guilty of shedding the small nozzle right after hole shot. We won the championship in Comp Jet in 1979 while doing it. We kept quite about it because it was a grey area as to being legal or not.
:D i wished i'da thought of that back in the biz daze. that thing had a .125 brass insert that was welded in there from firebird and we never got it out until we were all done. with the issues we always had off the rope, that woulda worked.

[steelcomp]

Thank You.....no......and yes I am:eek: :D
Now read the post that I replied to. blue wonder pops in shoots his mouth and offers nothing but the "look how wonderfull we are bs". No Question that BP has a stout set-up. Bracket racing doesn't prove or mean much to me, trying to running consistant #'s isn't pushing the envelope now is it....
And I agree with your last couple of sentences and that is why I will support people like Old Guy and others that come up with new ideas....and stomp on the time slip posersSo you thought you'd sound just as stupid as Blue Wonder. Good thinking.
Running consistant numbers isn't pushing the envelope? That says a lot. Too bad you don't see the amount of knowledge that must be involved in running a consistant number, at any lake, under any conditions, in any weather. It takes years to develop the data base to know just what to change, or not to change, in order to hit your number. You have to understand every working aspect of your boat and it's hardware, and what each and every change will accomplish. You have to know exactly what that shoe will do, what that nozzle will do, what that impeller will do, and so on. Anybody can throw a bunch of money at something and make it fast. Hell, like you guys do, just get in and floor it. You really don't even have to steer, you just run over whatever's in front of you. Big deal. Kinda wreckless if you ask me, but certainly not a lot of thinking there.
Take the kind of working knowledge that goes into a winning bracket racer's program, and turn it loose on going as fast as possible. What do you think the results would be?
And I agree with your last couple of sentences and that is why I will support people like Old Guy and others that come up with new ideas....and stomp on the time slip posersThat's just the attitude I was referring to.

[steelcomp]

You mean the attitude that comes with dealing with wannabee know-it-alls like you? Do you even have a running boat?Naw, I'm just guessing at all this. Do you?

[Cs19]

How did you retain the nozzle insert for the first part of the track then blow it out? Weak fasteners? Cable operated?

[steelcomp]

How did you retain the nozzle insert for the first part of the track then blow it out? Weak fasteners? Cable operated?How about a spring loaded detent (like a socket on a ratchet)...could be adjustable to release at different pressures

[Cs19]

How about a spring loaded detent (like a socket on a ratchet)...could be adjustable to release at different pressures
Good idea.
What about a way to retain the nozzle after it blows out?

[steelcomp]

Good idea.
What about a way to retain the nozzle after it blows out? I was thinking about that, too. Maybe an eye on the top of the insert sticking through a little slot in the nozzle, with something retractable attatched to it so it dosen't drag in the water. Maybe even a bungee cord or something? :eek: :sqeyes: OK...I've come up with better ideas. :notam:

[Cs19]

Bungee cord?:)
I say we make an insert that dissolves as we go down the track (Im joking)

[QuickJet]

I was thinking about that, too. Maybe an eye on the top of the insert sticking through a little slot in the nozzle, with something retractable attatched to it so it dosen't drag in the water. Maybe even a bungee cord or something? :eek: :sqeyes: OK...I've come up with better ideas. :notam:
I'm probably way off here but:
Why not make it an adjustable flange. Something cable operated where it reduces and expands. Something along these lines.
http://re3.mm-a6.yimg.com/image/3607567310

[cyclone]

OK guys could you do the guy who started the thread a favor and put your egos in check please?
i dont want to read the bashing. add something to the discussion of whether or not a nozzle with adjustable exit diameter will work or not and whether or not you can build it or not. leave the bench racing bs to another thread. i'm trying to learn something here.
thanks.
now lets get back to it.
duane-that's a pretty good idea you had about dumping the insert after the holeshot. was it attached to a cable so you could save it?
old guy- i like the feather idea. how would the bladder actuate it?

[Unchained]

I say we make an insert that dissolves as we go down the track
Now that's funny :D
Oh no, I heard "sliding shoe", things will certainly degrade from here.

[Cs19]

OK guys could you do the guy who started the thread a favor and put your egos in check please?
i dont want to read the bashing. add something to the discussion of whether or not a nozzle with adjustable exit diameter will work or not and whether or not you can build it or not. leave the bench racing bs to another thread. i'm trying to learn something here.
thanks.
now lets get back to it.
duane-that's a pretty good idea you had about dumping the insert after the holeshot. was it attached to a cable so you could save it?
old guy- i like the feather idea. how would the bladder actuate it?
:squiggle:

[Infomaniac]

Cyclone, Interesting. Your boat reacts to nozzle size change exactly like our boats do. That's why I asked the question earlier in this thread, "Are you positive the nozzle needs to go from large to small?"
When I was playing with my deal, I was going from small to large about 1/2 track. It almost felt like shifting gears. Of course back in those days, we had no means to record what we were really doing, and we were running under a flag system rather than a clock system, so there were NO time slips.
Well hell I'm excited again now about my varying nozzle idea.
I havent owned a jet in 14 years so I really didnt know what is best for hole shot and top end. I had assumed small to take off so it just doesnt blow all the water out faster than it can draw it in and open it up for top end to let it flow. For whatever reason, reading forums suggested the opposite.
:D :D

[Old Guy]

OK guys could you do the guy who started the thread a favor and put your egos in check please?
i dont want to read the bashing. add something to the discussion of whether or not a nozzle with adjustable exit diameter will work or not and whether or not you can build it or not. leave the bench racing bs to another thread. i'm trying to learn something here.
thanks.
now lets get back to it.
old guy- i like the feather idea. how would the bladder actuate it?
Basic concept involves a rubber liner inside a nozzle. Hydraulic pressure between the rubber and the nozzle housing causes the rubber to deflect inward. Thin stainless "feathers" between the rubber and the water make the effective inside dia of the nozzle smaller.
I appreciate the support from those here who are willing to see what it's about before criticizing. Also appreciate the information shared. I came here offering my services as machine builder, inventor, and interested party. I have over 40 years experience doing things that "can't be done" often using processes that "won't work, we tried that". I have made a very good living doing it. I'm retired now and staying very busy with lots of interesting projects.
I'm not going to discuss this any further here. I'm just not willing to pay the price of this kind of "discussion". If enough useful information gets posted, I'll try to do something with it. If anyone really wants to contact me, I'm not really that hard to find.
Some call it bashing, some call it flaming, I call it arrogant ignorance. I don't care to participate.
old

[steelcomp]

Well hell I'm excited again now about my varying nozzle idea.
I havent owned a jet in 14 years so I really didnt know what is best for hole shot and top end. I had assumed small to take off so it just doesnt blow all the water out faster than it can draw it in and open it up for top end to let it flow. For whatever reason, reading forums suggested the opposite.
:D :DRon, thast was probably me earlier, saying I thought it would be the opposite...large at the start for big hole shot, and then smaller as you went down the track for higher velocity, but I was wrong in that, and you're exactly right.

[Duane HTP]

We just had a pin hooked to a cable that let the nozzle out.
Yes, we tried retaining the ring. We put a cable on it and when it came out and hit the water, it sling shotted right past my head. That's when we decided to just let it go. So if you try this, make sure whatever retains the ring lifts it up away from dragging in the water and the jet thrust stream.

[Infomaniac]

Ron, thast was probably me earlier, saying I thought it would be the opposite...large at the start for big hole shot, and then smaller as you went down the track for higher velocity, but I was wrong in that, and you're exactly right.
Thanks for that man but that was not the first time I read or heard that point of view.

[cyclone]

We just had a pin hooked to a cable that let the nozzle out.
Yes, we tried retaining the ring. We put a cable on it and when it came out and hit the water, it sling shotted right past my head. That's when we decided to just let it go. So if you try this, make sure whatever retains the ring lifts it up away from dragging in the water and the jet thrust stream.
my forward reverse cable loops into the air pretty high so maybe if the insert was attached up high like that it would stay out of the water after its spit out of the nozzle. i'd like to find a way to keep the insert in place until just before half track before ejecting it. not sure if that would even be possible.
an adjustable nozzle would be nicer...

[Duane HTP]

I'll give you guys something to think about. This is why I quit doing it.
What if the nozzle bushing only came out 1/2 way and cocked crooked???????

[MikeF]

I'll give you guys something to think about. This is why I quit doing it.
What if the nozzle bushing only came out 1/2 way and cocked crooked???????
Cause you'll no longer have control which way the boat decides to go.:idea:

[bp]

I had assumed small to take off so it just doesnt blow all the water out faster than it can draw it in and open it up for top end to let it flow. For whatever reason, reading forums suggested the opposite.
:D :D
that's generally correct. at the hit for a boat going 0, increasing velocity slightly isn't as important as increasing mass, everything else being equal. but, you can only go so large, or you'll suck the intake so the pump partially cavitates (i know of one very successful retired racer that wanted to partially cavitate, because he felt he was right on the edge for max acceleration). conversely, with the boat at speed, the velocity need takes precedence.
the absolute fastest speed you can go is going to be limited by either mass or velocity (you can increase hp, but force will still be limited by one of these factors). one of those two factors will be maximized in the force equation. if you can get both to arrive at their limits simultaneously, you've optimized both acceleration and speed.
in duane's case (no offense here duane), he started off with an .06 and went to a .125. now, a .125 is a good medium performance diameter for any hp, and although duane didn't say, he usually raced with higher hp blower boats. in that case, a .06 will get you off the line without cavitating, with great velocitys, but is very restrictive for mass. with the change to the .125, a -significant- increase in mass flow instantly occurs (probably would have seen a reduction in bowl pressure at the same time with data), and velocity didn't reduce enough to negatively impact acceleration.
i am not necessarily suggesting that either small or large is "better" for launch, or top speed. i -am- saying that mass is more important than velocity at the hit, and both mass and velocity are needed for top speed. at different times during acceleration, one of these factors will take precedance in importance over the other.
i only have a little over 800hp in a very heavy boat. but i've made hundreds of 1/4 mile passes, testing everything from a 3.00 to a 3.23 insert. some might say that's only "seconds" of testing, but it's analysis and evaluation of data collected from each "test" that is time consuming. i don't mean to offend, but my view is that in higher hp applications, 1000hp or more, a 3.06 is way too restrictive. mass moves mass.
thinking about it, why are dual drives so effective in bigger boats (and they are, you just don't hear much about them). they don't "double" the velocity, but they do "double" the mass.

[cyclone]

ill agree with you on the insert sizing for high hp applications bob. 3.06 only helped my boat holeshot and hurt it down the track. opening up the nozzle netted a better overall et and mph even though the holeshot suffered.

[cyclone]

I'll give you guys something to think about. This is why I quit doing it.
What if the nozzle bushing only came out 1/2 way and cocked crooked???????
Well that's enough to keep me from trying it. dont think i'd make it through tech inspection with a set up like that anyway.
also raises the question of safety with some of the proposed adjustable nozzle designs. the "feathers" that old guy proposed could be dangerous if one "feather" didn't actuate and the others did. could send water to one side of the boat that could cause it to turn. hmm. maybe this whole thing isnt a good idea afterall.

[Red Rocket]

ill agree with you on the insert sizing for high hp applications bob. 3.06 only helped my boat holeshot and hurt it down the track. opening up the nozzle netted a better overall et and mph even though the holeshot suffered.
When you say holeshot do mean just getting of the rope and rolled over or are you talking about when it comes off the launch control.

[cyclone]

When you say holeshot do mean just getting of the rope and rolled over or are you talking about when it comes off the launch control.
idle to rolled over on plane. how's the new boat coming along?

[Red Rocket]

Things are supposed to start moving along faster after the first of the year. Just getting the motor ready and making some of the rigging right now.

[cyclone]

glad to hear it. yours should be incredibly light given how its being laid up.

[Red Rocket]

If all goes as it was explained to me it will be very light. I'm hoping it all works like they say, they are very confident it will be what I want.

[Placecraft Dragstar]

If ANYONE is interested in the duct I WILL SEND IT TO YOU FREE OF CHARGE to try even for Placecraft Dragstar. I will send it to you even if you just want to look at it. If someone wants to keep it and try it for a season, fine, they're easy to make.
See sstjet they dont cost a million, plus you dont even have to try it you can just look at it for a season.
It will be interesting to see what HTP comes up with in his testing and the two hulls he picked would be a good test. Then try a couple different locations and openings on how the duct is formed now. It could be interesting. Who is gonna try a gullwing hull??

[SkyHarborCowboy]

I can't say too much about this at this time, but what I can say is that within the next 12-24 months there will be a revolution in the jet drive industry. We have already produced and ran something that will change the way jetboats are viewed. Let's just say there's alot of room for improvement over all current jet drive designs.
It has been almost 25 months since this post was made. Any updates?
Joe

[shaun]

bump to the top

[nerve damage]

any updates anyone

[78_Tahiti]

I can't say too much about this at this time, but what I can say is that within the next 12-24 months there will be a revolution in the jet drive industry. We have already produced and ran something that will change the way jetboats are viewed. Let's just say there's alot of room for improvement over all current jet drive designs.
It has been almost 25 months since this post was made. Any updates?
Joe

Anyone!!! I am really interested in the variable intake idea as well! many may have seen the Intellijet. A little over complicated IMO. I would love to see some of the drawings or pics you guys have come up with.