jet pump performance tips

[wsm9808]

I'm rebuilding the Dom 12S pump in my 19ft Stallion tunnel/picklefork and was hoping you guys might have some tips on how to increase the accelleration/top speed from the pump while I'm in it. So far I've bought an AT "A" impeller and the wear ring clearance is .013 per side and I set the shoulder clearance at .026 . I "backfiled" the impeller exit vains to 3/32in, and sharpened the the leading edges of the bowl veins slightly. The hull intake to suction housing had a bad overhang/mismatch, so I smoothed and blended these together. Pump already has a shoe, rideplate, loader and place divertor with 3.125 nozzel. The old impeller had .040 per side clearance and was 9.125 OD. Boat only ran 60mph at 4600 rpm/ realy hope to improve on this.
Has anyone used one of those "bowl stuffers"? do they work at all?
Where can I buy a pop off valve for the hand hole?
Thanks for any help or comments. Scott

[flat broke]

Scott,
Good info on the clearances in the pump and what you've now set them to. With things being tighter you may see a loss of a couple RPM, but the efficiency should be much better. One thing that you didn't tell us is your engine setup. Without some specs and HP figures if you've got em, its hard to say what the pump will do. I would guess that if you were spining a loose fitting A cut at 4600, you are probably runing around the 300HP mark. A lot of it will come down to where your engine makes its ponies, but if it will rev higher(safely) than 4600, you should try matching the impeller pitch to that RPM. Just my $.02 I'm sure you'll be getting more responses shortly. The more info you give the board, the better the responses will be.
Good luck,
Chris

[Jetmugg]

Scott:
Once you have a properly built and set up pump, what you really need to go faster is more HP. 60 mph is typical for 4600 rpm, but I suspect you would much rather be running around 80 mph. To get there, you will need a more powerful engine. You might want to experiment with Jer's Jet Pump Calculator to get a rough idea of how much power you will need to reach your goal.
Steve.

[SCOTT]

Dominator pumps dont use bowl stuffer plates because there is a lip on the back of the impeller that fits inside the bowl.
THE OTHER SCOTT!

[hot_rod]

I can't tell you much myself but I had my dominator re-done by don, he is really good with dominator pumps and he could probally give you a few tips.
http://www.donspumpservice.com/
http://www.geocities.com/hot_rod20603/Hotrods_Jetboat_Page.html
http://www.bearshobbies.com/hotrods_signature.gif

[wsm9808]

Thanks for the info so far, I bought the boat in July. Motor is bbc 454 with 074 aluminum heads, 750 holley. Sounded real healhty on the trailer and didn't miss at all on the water, but the power was just way off (I also guessed it at about 300) and after a couple of hours the oil pressure started to drop.
Stopped it just in time, had a couple of spun rods and the mains lost their snap fit in the block, they where about to go too. Some one "rebuilt" this with motor with 4 galled pistons with up to .028 piston to wall clearance and 4 spun rods that looks like they dressed them with soom emery cloth and popped in some new bearings.
To make a long story short, I'm also rebuilding the motor, I just pulled the pump to check it and found it was full of junk also. The "new" short block is already together and I set it in the boat yesterday. Specs are .060 bore, .100 dome, Lunati cam- 230 dur @.050, .544 lift, 109 centers. Heads are not out of machine shop yet, but are square port cast #074 with some light bowl work. Should be about 8.75 compression, I left it a little low cause I want to add a BM 250 blower later with about 5# boost(just got one sniped out from under me on e-bay mon night). Carb is 750dp, but after I run it a few times, I want to add a 1150 dominator and see what happens, I,ve read jet boats love a lot of CFM. Anyone done such a swap? Wish I could have done the pump and motor seperate to check the changes, but I couldn't stand to put the pump back in the way it was.
Here is where it gets ugly, my area requires through transom exhaust, so I took off the OT headers and put on wet logs. Before you bash me, I don't want my kids getting burned on the injected through hull headers and I just couldn't make myself part with 3000.00 for jackeded headers and custom S pipes, and I alreaded had a set of logs. I still have the headers I can put them back on if I get the bug to see how much I'm loseing. Didn't lose anything when I put the logs on, but the motor wasn't right so it's not a true indicator. Thanks, Scott

[wsm9808]

Scott, I see what you mean about the shoulder on the back. Would it help pump effecency to face some off of the bowl flange where it mates to the suction housing? This would move the impeller deeper into the bowl and close the rear face clearance and move the leading edges of the bowl vanes closer to the exit vanes of the impeller. Or it might mix up the hydrodynamics of the pump. Anyone Know?

[squirt]

Scott, your right BBC with those heads love CFM, BUT.........but jet boats don't necessarily need the big cfm. With the exhust system you have choosen your motor will not rev high enough to use a big carb. You will get better performance and fuel economy with a smaller carb. I like the 715 vac sec. Holley, but up to 850 should work good. I wouldn't think any more would do you any good and more than likely slow you down. Just one mans opnion. Ask around there's lots of Info to be had, maybe call on a jet boat motor builder or pump guy and get their opnion.

[flat broke]

Scott,
I agree with Squirt on the carb issue. If you run the volumetric efficiency numbers on your motor, 750 is more than enough. There will be those that swear by 1150 cfm, or dual 750s, but before you throw down the cash, do the math with the VE formula, borrow a bigger carb (in equal state of tune to what you have) and decide for yourself.
On the exhaust, you don't have to shell out 3k for a decent set of manifolds. I picked up a brand new set of stainless marine manifolds with ss risers(not the crapy water through the junction style like some companies use) for $1600 from CP. Then another $40 in rubber to the tips. Its a 4" id system that works well and is a quality peice. If you wanted you could have the s pipes fabed to add to that setup for around $300(a quote I got when I thought I might need em). They wouldn't be jacketed, but they wouldn't need to be since the cooling water would be introduced from the riser that comes with the manifold.
Just some thoughts. Good luck with the rest of the build up and welcome to the board. Feel free to put some pictures of your baby up as soon as you have some time.
Chris

[Unchained]

wsm9808, Sounds like a fun new project. I would advise against a small blower like the B&M 250 or 177. They are a toy. You have to overdrive the hell out of them to make small boost. Get a real blower. A minimum of a 8-71 for a big block.

[wsm9808]

Thanks, I would like to post some pics, Flat, but I don't quite understand how to do it. I,m still a little new with computers and some simple things read like greek to me. Maybe someone could explain it real simple to me. It is a realy nice looking boat, the gel is perfect. Now, if I can just get it to run as good as it looks. I have enjoyed working on it so far though, looking forward to seeing how it runs now.

[Blown509Liberator]

I have to agree with Unchained on the little blower. Also after you over drive heck out of them the become a big heat pump along with the air. I am rumming a 6-71 and wish i would have gone 8-71. Goning to need to add an inner cooler. Also DONT BUY A USED BLOWER OFF E BAY. Buy your blower from a well known and respected shop like BDS. This is a big commitment and investment, cheap is not the way to go
MikeW
[This message has been edited by Blown509Liberator (edited October 12, 2001).]

[flat broke]

Originally posted by wsm9808:
Thanks, I would like to post some pics, Flat, but I don't quite understand how to do it. I,m still a little new with computers and some simple things read like greek to me. Maybe someone could explain it real simple to me. It is a realy nice looking boat, the gel is perfect. Now, if I can just get it to run as good as it looks. I have enjoyed working on it so far though, looking forward to seeing how it runs now.
Post your pics on a site that allows direct linking(geocities is not one of these sites). Then you copy the URL of your pics and place them in the format below.
Adding Images
To add a graphic within your message, just encase the URL of the graphic image as shown in the following example (UBB Code is the bracketed stuff).
http://www.prime-web.com/Ultimate20/tline.gif
In the example above, the UBB Code automatically makes the graphic visible in your message. Note: the "http://" part of the URL is REQUIRED for the [img] code. Also note: some UBB forums may disable the [img] tag support to prevent objectionable images from being viewed.
Hope that helps,
Chris

[wsm9808]

Chris,could you(or anyone) give me an example of a site that allows direct linking? I'm not sure what that is, and is it something you have to "join". I have used Honesty.com to post pics on ebay before they set up their own system. Could I link from Honesty? I don't see an example you refered to in you explanation, just a tiny box with an x in it? Thanks, Scott

[flat broke]

Scott,
The info I posted above was from this link
http://free.***boat.net/ubb/ubbcode.html
The example was theirs so I apologize for it not working. If you know the URL for the site you posted to, try using it in the UBB code. If it doesn't work its probably because that site doesn't allow linking. Photopoint.com used to allow linking but I'm not sure if they do anymore.
Good luck,
Chris

[wsm9808]

OK, I posted a pic on Excite, but I can't find the URL address for the photo on the page. How do you get the http:// address for your picture?

[Unchained]

WSM9808, E mail me your pics and I will
e mail you back the codes.
MNKRock@msn.com

[skeepwerkzaz]

I have the same heads that you do on a 454. I am running 1200cfm and over 600hp. My cam is well over 600 lift and 279 duration though. These heads are designed for alot of camshaft. They are the L-88 ZL-1 heads.
Later
skeep

[wsm9808]

mikew,(blown509liberator) You own a 21ft Liberaror, Right? that is what I was wanting to buy this summer. I went to Crowley Tx and talked with Dave this summer(I had 19ft Lib a few years back when I was single) about ordering a new 21ft hull. But everyone around here was talking trash about the boats, but none of them have owned one. I liked my 19ft Liberator pickle alot. How do you like your 21ft? I love the fact yours has an engine cover, its the only one I've seen with a cover.
I'm rebuilding this 19ft Stallion right now but I still want a bigger boat for the rougher waters on the bigger lakes. I'm putting a 468 back in the little Stallion, but I've got a 496 I'm building for the 21ft. The Stallion was advertized as a 21ft and I drove 980 miles, all the way to Alabama from west Texas to pick it up. When I got there it was a 19ft, but it was a real nice hull and priced right even for a 19ft so I bought it anyway to play with till the family figures out its to small for what they like to do. So I would still like to get into a nice 21ft pickle next summer.

[wsm9808]

Ta Da, with the help of Unchained and the other great guys on the board I was able to post these pics of my Stallion. Thanks everyone for welcoming me to the board.
http://www.childsdale-ind-prop.com/staliontrio.jpg
blown509lib, what kind of exhaust are you running? Do you have any pics of the motor/exhaust you could post are email me?
Thanks, Scott

[Blown509Liberator]

wsm9808
I love my Liberator. Yea I have heard the same crap. My favorite was "Cant make them fly even if you though them out of a plane". Well all I can say is BS.. I will say they have there good points and bad point about them. The hull and Gel was top notch. The rigging of the gauges and such could have been better and the seats and interior work where ok. The bottom of my 21' tunnel is the same bottom as a friend of mine's 21 Daytona. The big difference is the 8" of more transom on the liberator. My engine cover was made by Dave they are an option. Would I buy another one? You bet. I had Dave set the intake and I installed my motor and pump. I have run two motors in my Liberator First was a stock 502/502 the pump was a JG with a Legend Impeller it would run 5000 rpms and saw a best of 81 mph. and would run 78 mph any day. Now I have bumped up to 840 hp 509 Bow Tie big block. I am spinning the pump at 6000 rpms (at 800 hp and 700lb/Tq on the Dyno sheet) Bowl still stock, an "A" cut MPD prepped legend SS impeller. Set back pump with a MPD shoe and ride plate. I have spent the summer setting up the shoe and ride plate with this set up . I had a porpoise problem early this summer and pulled off a 94 mph with full tanks (50 gal) and two people in the boat. I have dialed out the hop and now moving the shoe ( back cut) down for more speed. I have run out of summer here in Chicago but I will say we will be seeing triple digits next summer
MikeW
P.S. I am running Gil's I will dig up a pic for ya

[wsm9808]

B509L, I really liked the 19ft Liberator I had too. It was a little heavier than most pickles that size, but that is what I wanted, a solid good riding LAKE boat that didn't feel like it was going to snap in half everytime I hit a wake like some of the ulta light hulls I had been in. Like I said before, none of the people I know that where trashing the boats have ever owned one. But, I,ve never been in any 21ft and I wouldn't have anything to compair it too if I drove one. I'm glad to hear your satisfide with yours, from what I can tell the Libs are solid boats and all of them I've seen have had flawless finishes, and you can power them as mild or wild as you want. To me they appear to be alot of boat for the money because they are not real expensive compaired to some others.