So the stupid bug won't go away and I'm constantly thinking of ways to get just a little more MPH out of my tank of a jet boat. I'm at 57.5 mph on gps rite now and would like more...

So without tearing into the motor (to late in the season for that). Is there anything else I can do to the pump to get me some more mph? The pump is a fresh 12jg with a new aluminum A impeller from JBP, has a ride plate set a 2 1/2 degrees up, loader of unknow brand, Place HPH, Hydraulic diverter.

I know the bowl has a a few nicks in the entry fins. I cleaned it up as best I could with a file and such. So do you think my boat would benifit from any further bowl work? Extrude hone? Porting? American turbine bowl? Maybe a full droop snoot?

Anything else that I'm missing?

Thanks in advance for the help.


Pic of the loader


Pic of the curent pump set up

I think you're hurting your MPH with that A impeller, try either a B cut or an A/B cut. A full droop might help lift the ass end of the boat out of the water some more, free it up a little. If you decide to do the full droop I've got one I'll happily trade you for the HPH unit.


Oh yeah, what RPM are you turning at the 57.5 MPH? Where is your diverter set? You should see about a 3'-5' rooster tail about 100' off the boat, once you find that sweet spot, you'll be golden.

Let me know if you want to do the droop deal, also keep me up to snuff on how the changes do.

Good Luck
Skip

The motors at 4750rpm's with the A. Previously it had a B in it and was seeing 54mph @4900rpms. Granted that impeller was pretty chewed up, it had some rock chunks missing courtesy of the previous owner.

As far as diverter setting. I have seen the best results with the roost just about 1-2 feet above the water. I'm still gonna experiment some more with that.

The hull has no hook and rides rather high out of the water already. I have read that a full droop is usually not good for bigger boats but I have though about experimenting anyways.

FWIW. That setup looks like a droop would respond well, definately worth a try anyways.

Droops are bow lifters not transom lifters, if the boat runs "dry" like you say, does it get into a porpoise when trimmed up? if not a droop for sure.

At almost 4800 RPM with an "A" impeller, I would have to say you are moving enough water, it's just not in the right place. I would bet a droop would make you see 62-65 MPH without much else as a mod...Also, make the boat lighter by getting rid of anything unecissary, you know, kids, soda pop (gotta keep the beer), beach toys and so on.

Another negative comment, I do not like those loaders, it may be hurting you. Have you tried a rock grate? What you're looking for in a loader is a curved ramp IMO.

And sorry Skipper, disagree on the smaller impy, he's outa motor now...

GT

FWIW. That setup looks like a droop would respond well, definately worth a try anyways.

Droops are bow lifters not transom lifters, if the boat runs "dry" like you say, does it get into a porpoise when trimmed up? if not a droop for sure.

At almost 4800 RPM with an "A" impeller, I would have to say you are moving enough water, it's just not in the right place. I would bet a droop would make you see 62-65 MPH without much else as a mod...Also, make the boat lighter by getting rid of anything unecissary, you know, kids, soda pop (gotta keep the beer), beach toys and so on.

Another negative comment, I do not like those loaders, it may be hurting you. Have you tried a rock grate? What you're looking for in a loader is a curved ramp IMO.

And sorry Skipper, disagree on the smaller impy, he's outa motor now...

GT

Well hell at least I had one thing right  The droop is probably going to be your best bet John, try a droop, and a "sport" loader, I'm not convinced that a stock grate will help you. Offer still stands if you want a droop snoot.

Skip

GT- You're like Cliff Claven, except your knowledge is actually useful! Thanks for your input here and on other threads, I actually have learned shit from you, yeah, kinda scary huh?

Thanks for all the help. I'll try and answer all the questions as best I can.

As far as what kind of intake it is. I have no idea. Sorry

The current loader is about an 1/8" above the bottom of the boat. I do not have the stock rock grate either the boat came to me with this loader already installed.

Ride plate is 14 1/2" from the longest points on the front to the rear.

The boat will porpoise like crazy if the roost is not set level to the water or below @ cruising speed. At WOT it can go all the way up no problem.

As far as weight goes I try not to carry anything more than I need. I come from a car drag racing background so I know how crucial weight can be. The GPS speed was with me and my girl, both tanks were about 3/4's full.

My only issue with a full droop is my boat cover. I had a custom cover made last summer $$$ and it covers the whole pump and swim steps and all the way down the sides of the boat. I don't think it would fit if the pump is another 4" or so longer.

What would be a good loader to get?

Where would I get a longer rideplate?

So what about some bowl work? No? Not worth it?

Again I really appreciate all the help.

Ultra460,
 As far as the droop being longer, it shouldn't be that much longer than what you have. Mine (full droop) is only 6 1/2" long from the flange to the upper steering pin.

 The reason I asked about the intake was because it doesn't look familiar to me.  It might be an aftermarket low profile intake.  If it is I would think it would need a special loader (not sure on this).  Take a good look at it for any names or numbers.  Someone should be able to ID it so you know what your working with.

 I'll leave the other questions for those with more experience then me.   

I will try and get a better look at the intake tommorow in the day light. I'll get some pics also. Thanks for the help.

I belive but 57 for that boat  is pretty respectable .

Hell Yeah it is! My 21' GPS'd at between 44 and 48 all day last weekend, very dissapointing, but my son (14) keeps threatening me if I try and hot rod it to make it too fast. (My goal is 65 MAX, else he won't want any part of it).

Talked to Nordie the other day and B-rads 21' did 58 on GPS, (to which they were all amazed), so that's where I'm aiming. Shouldn't be ANYWHERE near as radical as the Moo, just a touch here and there should do it. (I already have a place diverter on this one)

Ray

What do you guys think about this loader? Any good?

http://www.performancejet.com/whitelighteningNEW.htm

I dont know one loader from another but from what I can remember. Aren't Loaders very "Boat Specific"? Meaning it could inhance the performance on one boat but hurt the performance of another?

I know someone on here at one time said "Loaders are Trial and Error, Put one on and try it. Put another one on and try it, etc etc. Eventually you will find the one that works perfect for your ride"

I'm not so sure you would benifit from a loader as well , it may even "pull" you down  a little , your boat is a smidge on the heavy side ! Tom

Jbp semi Pro