hey LV, I'm interested in your numbers

[superdave013]

:D
Just so you know that someone does dare to care.
I take it that the Dave that's doing your engine is Dave @ DNE right? If so look me up when you come out. I'm pretty close to his shop.
OK, now you have predicted your numbers. Now it's time to hear my predections. :D
My objective is not so much top end speed. I want a high cruise speed. I.E. I wanna cruise @ 75-80 with out a sweat. That's with a cooler, back seat and my two 45gal fuel tanks full. Oh, it's gotta run on pump gas too.
So here's my plan.
Take my ten ton (don't know the real weight but the bottoms 1 1/2" thick) 20' schiada and rig it with all new hardware (inluding angles and location) and engine.
The boats getting a new drop through strut placed 21" from the barrel to the back of the boat. A Menkens billet v drive is getting installed with 48% gears in the box. The prop that I'm going to try first is a high rake (V Drive Tom's idea) [B]11.5x16{/B] two blade. (might end up with a standard rake but want to try this one first)
Engine is a twin turbo 572" deal with draw thru carbs. Wste gates will be set at 10 pounds. I'm not going to dyno it. Just take some plug reading and get the jetting close as I can and run it.
What's the top speed going to be? Well it's getting a 6,500 RPM rev limmiter and if it hits that it should be freaking hualing the bacon. I don't think that I'll be trying to get the last little bit out of it. On paper it should run over 120.00. In real life I don't know if I'll have the balls to run it that hard.
Remember, my objective is a fast cruise speed and I know I'll be happy with the result (if I ever get it done).

[LVjetboy]

Yep, that'd be the man. Karen and I'll swing by the shop Saturday(?) if you'll be around then we can say hi. If you email me a number maybe we could meet? Karen loves speed but she's definitely not a motor head so I won't say too long. If we don't hook up then, see you at the Bash?
I'm interested in your plans. If you can cruise at 80 with a heavy 20'...that'd be cool. Here's what I'm wondering...
What are you estimating for power at 10 lbs boost? Wouldn't a dyno run be good to make sure you're not detonating on pump gas? What does 48% gears mean...is that percent reduction? Does Menkins publish gearbox efficiency numbers like hpout/hpin at a given rpm? Also, this could be a whole 'nother thread and I'm spending too much time in v's already :) but...what do v-drivers think about that crazy power vs. torque issue the pump guys are always talking about?
jer

[U-Haul]

Dave it has been a while since you have posted pictures of the boat progress. I appriciate the craftmanship you put in to the small details and would like to see what you have done lately? If you can please post them.

[havasulew]

I'm running a 21' Rush Performance. Blown 588 with 48% overdrive. The prop is one of Harold Kindsvater's 11 3/4" X 17" high rake/wide blade. I estimate boat weight with 70gals of fuel and cooler to be about 3700lbs. Cruising at 4000 rpm speed is in the low 70's. At 4500 rpm speed increases considerably, the boat is finally starting to get free.

[superdave013]

LVjetboy:
Yep, that'd be the man. Karen and I'll swing by the shop Saturday(?) if you'll be around then we can say hi. If you email me a number maybe we could meet? Karen loves speed but she's definitely not a motor head so I won't say too long. If we don't hook up then, see you at the Bash?
I'm interested in your plans. If you can cruise at 80 with a heavy 20'...that'd be cool. Here's what I'm wondering...
What are you estimating for power at 10 lbs boost? Wouldn't a dyno run be good to make sure you're not detonating on pump gas? What does 48% gears mean...is that percent reduction? Does Menkins publish gearbox efficiency numbers like hpout/hpin at a given rpm? Also, this could be a whole 'nother thread and I'm spending too much time in v's already :) but...what do v-drivers think about that crazy power vs. torque issue the pump guys are always talking about?
jer George @ Clay Smith dynoed a little smaller cubic inch deal @ a little over 1,000 hp with 6 psi. So my deal has alot better headers and the heads have had a little more work done to them. I should be over 1,000 hp. And yes, dyno would be a good thing to do but I'm not going to. As soon as it's done it's going in the boat and I'm going to the lake. I've played around with enough blower deals to feel I can get away with 30 degress of timming and 10 psi. I might start off with less boost and work my way up.
48% means that the prop spins 48% faster then the crank. That's why a good steel prop is a must. Anything else and it flings the blades off the hub with that kind of RPM.
I don't think Menkens has published any gearbox efficiency numbers. It's just 2 gears and a few bearings. I know there is a loss and I'm sure it changes with every different ratio.

[superdave013]

havasulew:
I'm running a 21' Rush Performance. Blown 588 with 48% overdrive. The prop is one of Harold Kindsvater's 11 3/4" X 17" high rake/wide blade. I estimate boat weight with 70gals of fuel and cooler to be about 3700lbs. Cruising at 4000 rpm speed is in the low 70's. At 4500 rpm speed increases considerably, the boat is finally starting to get free. Sounds like my thinking is pretty close then. I took a peek at your boat at Needles. At least I think it was yours. Nice rig for sure.

[superdave013]

U-Haul:
Dave it has been a while since you have posted pictures of the boat progress. I appriciate the craftmanship you put in to the small details and would like to see what you have done lately? If you can please post them. WOW, don't know what to say but THANKS!
I have not posted anything because I've been working on everything but my boat. I'm back on it now and as we speek and something cooking on the mill. When it's done I'll slap up some pics.

[Backfire]

What does 48% gears mean...is that percent reduction? Does Menkins publish gearbox efficiency numbers like hpout/hpin at a given rpm? jer [/QB]48% gears means overdrive ratio meaning propshaft RPM is 1.48 times engine RPM since Dave's t-400 has a 1-1 ratio. Prop pitch of 16 means that, as a screw, the prop produces 16 inches of forward travel per revolution

[058]

In reply to the HP vs. Torque I think too much time has been wasted on this subject. It isn't all that complicated... torque is the measurement of work in ft/lbs and horsepower is a measurement of torque and speed. You cannot have a horsepower figure without the torque value. The 5252 figure is nothing more than a constantant use to find the horsepower figure from the torque value. I see many people think the 5252 figure is where torque and HP intersect on a graph which is bogus, if that be the case then you would need to spin large diesel engines far above their rated engine speed to calculate their HP level. The bigger the engine the slower it needs to spin. Some of the biggest industrial internal combustion engines only spin 90 to 100 rpms so where does the 5252 figure into the specs of these engines? And the next question will be "Then why does the hp level keep climbing long after torque starts dropping off...?" :D

[GofastRacer]

superdave013:
havasulew:
I'm running a 21' Rush Performance. Blown 588 with 48% overdrive. The prop is one of Harold Kindsvater's 11 3/4" X 17" high rake/wide blade. I estimate boat weight with 70gals of fuel and cooler to be about 3700lbs. Cruising at 4000 rpm speed is in the low 70's. At 4500 rpm speed increases considerably, the boat is finally starting to get free. Sounds like my thinking is pretty close then. I took a peek at your boat at Needles. At least I think it was yours. Nice rig for sure. Trust me Dave, Grier took me for a ride in his, they are the shit, best ride I ever had in a cruiser!.. :cool: :cool:

[Jetboatguru]

058:
In reply to the HP vs. Torque I think too much time has been wasted on this subject. It isn't all that complicated... torque is the measurement of work in ft/lbs and horsepower is a measurement of torque and speed. You cannot have a horsepower figure without the torque value. The 5252 figure is nothing more than a constantant use to find the horsepower figure from the torque value. I see many people think the 5252 figure is where torque and HP intersect on a graph which is bogus, if that be the case then you would need to spin large diesel engines far above their rated engine speed to calculate their HP level. The bigger the engine the slower it needs to spin. Some of the biggest industrial internal combustion engines only spin 90 to 100 rpms so where does the 5252 figure into the specs of these engines? And the next question will be "Then why does the hp level keep climbing long after torque starts dropping off...?" :D Ole 058 doesnt "F" around.
Go get em Bob!!

[havasulew]

Superdave---I was at Needles. I'd have to say that if you saw a Rush boat there it was mine. Thanks for the compliment about the boat. Make sure you say hello the next time you see the boat.

[SK48]

I have had the pleasure to ride in the right seat of Lew's Rush and it is an awsome pleasure boat. I was fortunate enough to ride with Mike Hoban in the pink GN 30 boat at wide open 128 and change. The best experience of my life was driving the GN 30 Rush as fast as I could. Never had it wide open, but i couldn't see where I was going.
The turbo motor is kind of scary without a helmet on. It is so quiet (exhaust noise) that you can hear everything else, that you don't really want to hear.
Dave your boat should be awsome !!!

[GofastRacer]

havasulew:
Superdave---I was at Needles. I'd have to say that if you saw a Rush boat there it was mine. Thanks for the compliment about the boat. Make sure you say hello the next time you see the boat. Yep, it was the only one there, hey Lew, next time I see ya at Red Rock, I want a ride in that badass baby!.. :D
http://www.***boat.com/image_center/data/520/12Lew_s_Rush.jpg

[LVjetboy]

Thanks SuperDave and Backfire for the info on 48% gears. A few jetters run gears so I was curious. Copy overdrive and no efficiency numbers. I'm thinking the answer (on pump efficiency vs rpm) from Berkeley the same...no info. Emailed them last week....still waiting. SuperDave, I'd like to see your pictures too.
058, I know you're v but you hang w/jets too so I assume you've read the jet hp vs Q threads? Looks like we agree the mystical 5252 rpm not significant. Yes hp and Q curves intersect at 5252 rpm in English units, but who cares? An urban myth in my opinion. I think I posted that last year in this thread?
Mystical 5252 rpm (http://forums.***boat.net/ubb/ultimatebb.php?ubb=get_topic;f=11;t=001138#000027)
On the measurement of torque and hp, units, etc. Seems we agree there too. You can't have one without the other. You need torque for hp. If you have power you also got torque. Seems simple enough. Anyone can look up definitions and units. And nobody I know disputes these points. You can bet that any engine with power also has torque? By definition that is. But I'm looking for deeper thoughts on which property best reflects the performance of a v-drive.
From the v-drive regulars that is.
On the performance issue...that's where I've noticed opinions differ...both in boat and car worlds. As for "isn't all that complicated?" Maybe not that complicated, but then why the confusion? Not only in the boat world but also in car world? If you have it figured for v-drives post away.
I'm thinking there's things not fully understood.
Urban myths, rumors, what an "expert" told you, whatever. In the end, it comes down to something not well understood between power and torque. Drive properties may have something to do with it. How a "performance vehicle" interacts with the enviroment may have something to do with performance. Traction versus prop slip or impeller cavitation another thing. Accepting what others say not always best. So why is posting about hp vs Q a waste of time? I'm thinking, the more people who think and post their thoughts about hp vs Q the better.
So I don't agree with your "wasting time" thing. What goes on with power and torque may seem simple on the outside, and a waste of time in your opinion 058, but more complex and worth understanding to others.
That's why I'd like to get the v-drive perspective.
I've already seen first hand how jet boat racers (differing) views on hp and Q influenced their decisions on the ideal race setup. So just curious about v-drivers. Those I haven't already heard from yet? Do props behave differently in this issue?
Ya I know...blah, blah, blah...
jer
[ June 04, 2003, 01:36 AM: Message edited by: LVjetboy ]

[RaysonKid]

Superdave and jetloverboy,
Here are some interesting numbers to chew on.
* Dragsters reach over 300 miles per hour before you have read this sentence. * Top Fuel Engines ONLY turn 540 revolutions from light to light!
* The redline is actually quite high at 9500rpm.
Hmmmm, Gives Revolutions Per Minute a whole new meaning.
[ June 03, 2003, 11:53 PM: Message edited by: RaysonKid ]

[LVjetboy]

Ok, Rayson, I'm game...can you explain your post further?
[ June 04, 2003, 12:17 AM: Message edited by: LVjetboy ]

[RaysonKid]

I had a hard time dealing with that one in my head.
But it makes sence.
A top fuel dragster only runs about 4.80 seconds.
And they turn 8,000 to 9,000 R.P.M. or something like that.(so the key words are seconds and minutes).
Heres some more facts.
* One dragster's 500-inch Hemi makes more horsepower then the first 8 rows at Daytona. * Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro per second, the same rate of fuel consumption as a fully loaded 747, but with 4times the energy volume.
* The supercharger takes more power to drive then a stock hemi makes.

[RaysonKid]

never mind.
[ June 04, 2003, 06:34 AM: Message edited by: RaysonKid ]

[superdave013]

RaysonKid:
Superdave and jetloverboy,
Here are some interesting numbers to chew on.
* Dragsters reach over 300 miles per hour before you have read this sentence. * Top Fuel Engines ONLY turn 540 revolutions from light to light!
* The redline is actually quite high at 9500rpm.
Hmmmm, Gives Revolutions Per Minute a whole new meaning. That was some good stuff.... the first time I read it here on ***boat. :rolleyes:
I think blown472 posted that.

[Infomaniac]

You can always count me in on this debate.
Never mentioned is how max torque and max HP is obtained.
Peak torque occurs when maximum cylinder filling occurs. This will be at a lower RPM when there is enough "time" to fill the cylinder.
As RPM's increase there is not enough "time"
to fill the cylinder so torque drops off. HP increases because there are more power strokes per minute. This offsets the loss of torque.
Plus the fact that it is a mathmatical calculation.
My official position remains - if your engine runs lower RPM's buy components that maximize torque. If it turns big RPM's buy components that maximize HP.
Regardless of your personal opinions. You must speak the same language as the parts manufacturers. Torque and HP.

[Blown 472]

nope, not me.

[LVjetboy]

Ok, one thing I'm wondering is, when SuperDave picks his 48% gears, does he try to match peak engine power to his prop, or peak torque, or something in between that has nothing to do with engine power and torque?
How does a v-driver pick gears? And prop for best acceleration and/or top speed? Say for example if engine reliability or valve train float were not issues. Is the engine's power or torque curve a consideration? Or are there different issues more important. I've seen all that from the jet boat view, but wondering if there's common ground for you guys.
jer
[ June 04, 2003, 09:42 AM: Message edited by: LVjetboy ]

[superdave013]

LVjetboy:
Ok, one thing I'm wondering is, when SuperDave picks his 48% gears, does he try to match peak engine power to his prop, or peak torque, or something in between that has nothing to do with engine power and torque?
How does a v-driver pick gears? And prop for best acceleration and/or top speed? Is the engine's power or torque curve a consideration? Or are there different issues more important. I've seen all that from the jet boat view, but wondering if there's common ground for you guys.
jer My engine combo came from Clay Smith Cams. George over there set me up with all my parts based on what I wanted to do with the boat. He told me what RPM I should gear/prop the boat for. This is a daycruiser and not a drag boat. It has a flattappet cam and he doen't want to see me spin it over 6,500. That's why I picked that big gear. It should still leave pretty hard as I'll take off in low gear and then just upshift when the boat gets moving.
Now with my flat it was not the same story. I wanted the boat to be quick and I ran a shorter gear in it. That boat had a big roller that loved RPM. With a 25% gear it would hit almost 9K off the line and was in the mid 8K range at the lights.
So selcting a prop and gear combo could be different for 2 people with the same boat.
Say you have 2 guys with Hondo flatbottoms with 468" hot rod tunnel ram deals in them.
Guy #1 wants to be the bad ass of the lake. (I'll go on a limb and say he has a bigger cam too)
Guy #2 pulles his kids sking and wants in to cruise at a good clip and still have an good top end for the every now and then gas mashing.
I would suggest that guy #1 run a shorter gear the guy #2.
Guy #1 would have say a 15% and it would launch like a mofo. Would also turn some RPM too.
Guy #2 would have an 18 or 22% and his boat would still run pretty good but would not turn over 6 - 6.5K. It wouldn't rev like a buzz saw off the line and would pull his kid on the tube @ 1,800 rpm. That guy can go all day on 15gal of gas.
In a drag race guy #1 would kill guy #2.
It all come down to what are you trying to do and what your using your boat for.

[superdave013]

Oh, I will go on record saying that lots of v drive guys over gear their boats.
I guess it's a mocho thing to be able to say I pull a 22% gear when they would be much quicker and maybe even faster with a 12 or 15%.

[Sangster]

I hate Numbers....There's like too Many of them.... :rolleyes: :rolleyes: :rolleyes:

[LVjetboy]

SuperDave,
I have a question on what your said about ratios...but speaking of numbers, I gotta run to catch a flight to LA, make sure Dave's putting enough of them in my engine :)
Back later.
jer

[058]

Infomaniac:
You can always count me in on this debate.
Never mentioned is how max torque and max HP is obtained.
Peak torque occurs when maximum cylinder filling occurs. This will be at a lower RPM when there is enough "time" to fill the cylinder.
As RPM's increase there is not enough "time"
to fill the cylinder so torque drops off. HP increases because there are more power strokes per minute. This offsets the loss of torque.
Plus the fact that it is a mathmatical calculation.
My official position remains - if your engine runs lower RPM's buy components that maximize torque. If it turns big RPM's buy components that maximize HP.
Regardless of your personal opinions. You must speak the same language as the parts manufacturers. Torque and HP. We have a winner!! For your simple and well thought out explanation you win a cookie.... :D

[havasulew]

GoFast--next time you see me give me a heads up. I do know that I will be at Red Rock 7/20 and 7/21.

[wsuwrhr]

Shot you five for that info. I have never been able to explain it better.
Brian

[LVjetboy]

Back from LA. 058 and wsuwrhr, glad you guys know the secrets to torque and hp...just couldn't explain.
Info, I have questions about your post. Almost decided not to reply...loosing some interest...maybe wasting time.
Never mentioned is how max torque and max HP is obtained.This could be interesting, although my focus is which property more important to performance (acceleration and top speed). But this a new angle.
Peak torque occurs when maximum cylinder filling occurs. This will be at a lower RPM when there is enough "time" to fill the cylinder. As RPM's increase there is not enough "time" to fill the cylinder so torque drops off. HP increases because there are more power strokes per minute.Sounds good. So does torque dropping off hurt performance? If so, where is the cutoff? The magical 5252 rpm or some other rpm? Or if torque dropping off is offset by hp increasing, then is torque only important in how it is able to increase hp? Or is there some other cutoff before power peak?
Plus the fact that it <hp> is a mathmatical calculation.Both torque and hp are mathematical calculations, some choose to believe, some not.
My official position remains - if your engine runs lower RPM's buy components that maximize torque. If it turns big RPM's buy components that maximize HP.Your position seems clear to me. As I suppose some view mine. But again, your position seems to imply an artificial cutoff point where somehow torque importance is replaced by power importance. I'm thinking there is no cutoff.
Now consider an alternative. What if boat performance is dictated by power alone? Period. No matter the rpm? Independent of torque? In other words, for any full-throttle rpm, the amount of power supplied to the prop or impeller is key alone to predicting thrust and performance? Not torque?
Consider the gearbox. When George @ Clay Smith recommends gears for performance (acceleration and top speed), does he pick gears for maximum engine torque or maximum engine power?
SuperDave mentioned mechanical reliability issues (cam), gas mileage (tow boat), acceleration and top speed. Changing ratios certainly influences reliability and efficiency, but power in = power out ignoring losses. Conservation of energy. So why the best acceleration and top speed (performance) with the shorter(?) gears? I'm thinking because shorter gears allows the engine to get closer to peak power? Of course if you define performance as best cruise economy and engine life than all bets off.
Regardless of your personal opinions. You must speak the same language as the parts manufacturers. Torque and HP.When it comes to building engine, I have no doubt. The hp vs q debate is more theory than matching parts, measuring clearances or torqing bolts. But still interesting (to me at least) because sometimes "theory" ends influencing those who race.
jer

[Infomaniac]

All this discussion is interesting and not necessairily a waste of time.
It is in fact all theory. The real test is who builds the fastest boat.
As far as the subject is concerned.
If your engine runs a fairly low RPM - select components that fill the cylinder the best.
If your engine runs higher RPM's - Shoot for the moon. The more power strokes per minute will ultimately produce the most power.
And what RPM is all of that? Who knows? All it does is get you thinking a bit deeper than the other folks. It is bound to help you with building power. Regardless of your opinion vs someone elses opinion. It does not matter.
I seem to be fairly sucessful making boats go fast. That is the bottom line anyway right?

[GofastRacer]

havasulew:
GoFast--next time you see me give me a heads up. I do know that I will be at Red Rock 7/20 and 7/21. You got it!.. wink :cool:

[LVjetboy]

I seem to be fairly sucessful making boats go fast. That is the bottom line anyway right? I've certainly seen your work...in action :) And just because I have strong opinions on the hp vs q thing doesn't mean I discount your engine expertise. Just that I question everything...even "accepted" knowledge. Some of the great engine builders and racers are the first to admit they learn new things all the time. I heard of an experiment where a jet racer impellered to match peak torque, then to match peak power with interesting results. Usually jet boats don't have the flexibility to play with gear ratios...altering output torque, but seems the gearbox can shed some light on power vs torque.
Then there's always the uhm, clamp on guys. Wonder what they think about this? :)
jer

[Rexone]

LVjetboy:
[Just that I question everything...even "accepted" knowledge. jer Uhh that's no shit.
(j/k with you jer). :D

[Monkey Bung]

LV can we get some updates on the stereo system in the boat please.

[058]

Bung! Thought you dropped off the face of the earth. Welcome back.

[LVjetboy]

Monkey, no problem. I can post pictures of the new subs in the bow, amps and stereo box upgrade, if you're interested.
jer
[ June 11, 2003, 01:41 AM: Message edited by: LVjetboy ]