[Uminchu]

Hi all,
I've read these forums for the past few hours trying to figure out where I need to go with my setup. I got some good info.

Hull is 18' Starbuck (jet) with the stern molded to match the contours of the pump. Current pump is Berk A, aluminum impeller, and seems tight.

Engine (being built) is 496 roller with stock 990 heads. (Forged internals) Builder says easily 600HP on pump gas.

Questions: What max. RPM/torque should we cam for? I am thinking something around 5600?

At 600 HP, do I need to change to bronze or stainless?

I realize there needs to be more information to figure this, but hoped someone out there could get me in the ball park. This is not a race boat of course, but a lake hotrod that I would like to hold together.

Thanks!

 

[Fonz69]

pm sent

 

[H20MOFO]

Hi all,
I've read these forums for the past few hours trying to figure out where I need to go with my setup. I got some good info.

Hull is 18' Starbuck (jet) with the stern molded to match the contours of the pump. Current pump is Berk A, aluminum impeller, and seems tight.

Engine (being built) is 496 roller with stock 990 heads. (Forged internals) Builder says easily 600HP on pump gas.

Questions: What max. RPM/torque should we cam for? I am thinking something around 5600?

At 600 HP, do I need to change to bronze or stainless?

I realize there needs to be more information to figure this, but hoped someone out there could get me in the ball park. This is not a race boat of course, but a lake hotrod that I would like to hold together.

Thanks!

At 600 horses..I'd go with a stainless or bronze , if nothing else for peace of mind. Look fwd to seeing it.devil

 

[Pro Mod]

bronze agg A then start tuning

 

[jetboatperformance]

Your 600 hp is way beyond the OEM hp recommendations for aluminum impellers of 450 to 500 hp as said above that puts you in the Stainless or Bronze Impeller category as far as the cut once more everything depends on your engine build and where it makes power as well as the hull itself not to mention what your going to do with the boat. Cam choice is going to nrelate to your budjet and application as well as Compression , induction , exaust etc As Pro mod said start big (Impeller) and tune Tom

 

[Uminchu]

everything depends on your engine build and where it makes power as well as the hull itself not to mention what your going to do with the boat.

It'll never be a race boat, but the two times I had it out before shelling the rear main bearing, it handled real well.

Cam choice is going to nrelate to your budjet and application as well as Compression , induction , exaust etc As Pro mod said start big (Impeller) and tune Tom

I am trying to keep it simple with max power developed in the mid to upper 5K range. I have a very competent builder working that aspect of it.

Thanks Tom, and all who responded here. I think I know where to go with this. Dave

 

[lefty's pride]

hey you and me are in the same boat. im looking for a good imp chart as well, it bugs me every one says how much power are you making and where are you making it. then you go to your engine builder and he asks you "well how much power do you want and where do you want it" no body given a good answer i found one ok chart at dominator

H.P.9.59.25AAABC15029003050320036003800405020032003350350040004200445025034503600370043004500480030038003950405045504800510035040504200430047505100535040042504400450050505300560045044504600470052505500585050046504800495054005700605055048004950510055505850N/A*THESE RPM VALUES MAY VARY ACCORDING TO HOW YOUR BOAT ALLOWS THE PUMP TO LOADHORSE POWER REQUIREMENTS ARE AT THE PUMP SHAFT
Good luck with your search​

 

[lefty's pride]

http://www.americanturbine.com/information/impeller_chart_sd309.htm
ok im sorry that looked way better in the post and it is american turbine