turbo charged
 

My friend is building an ex Navy Seal HSB and this is what he is using for power. What do you think?

the exhaust is designed to go out of the bottom of the boat

from what I see its a draw through the carb set up wouldnt touch it with a 10' pole. No matter what you do the seals in the compressor end will allow oil and fuel to mix into the engine and turbo causing damage. If those turbos have no seals big trouble. No seal can withstand the RPMs a turbo runs at. Go blow through or injection and it will live for years providing boost is not higher than the engine components can handle.

I have wondered about the pros and cons to a draw thru system. I had a blow thru system a few years ago. It ran well but was difficult to prop for getting on plane with very little boost, then having the prop want to blowout once boost came on.

Depends on how much the compression is lowered. Low compressionn with serious boost and a boat might never get on plane. In this situation a 2 sp transmission helps, a low gear to reach planing speed and turbo spool up hit second and your gone. Low boost aplications the compresion can be left high enough the engine will have enough power to plane the boat before boost cuts in.
Makes it sound easy but its not turbos produce tork lots of it or high HP also depending on sizing ... intent. I did a 460 goal was same HP as stock 375. 10 lbs of boost c/r around 7.5 pulled 375 HP and 800 lbs of tork. An indy engine the old turbo Cosworth Fords were more HP didnt have any power untill 4000 RPM from there the graph was almost a vertical line. Most aplications in the performance world start out with too much power then they are detuned so they can hook up to whats avilable gearing, tire sizes, prop size, etc.

I like for it to look as good as it runs. These set ups just look like they belong in a 1972 jet boat. Even that new 1200 that chief did still has the same goofy looking log exhaust....he tried to dress it up but I still think it looks dated. I understand this is a navy boat....I hope it works out. All I have heard is horror stories. I have personally had two experiences with twin turbo's......my first and last! The motor blew apart so severely that we had to repaint the bilge!! That was years ago and I am sure technology has come along way.

Footnote.......we also had no idea what we were doing......but Gale banks built the motor.......and I will have to say, the banks motor blew up bigger than anything else I have ever seen......so in that respect it was truly high performance.

Had a Gale Banks Twin turbo setup like that for about 20 years. Tore up a few motors but was running the motors on the edge. I had added waste gates with a dial on the dash. I could adjust the boost from 5lbs to 15 just by turning the dial. With the waste gates the motor would build 5 llbs of boost just off idle.

Good to see the old girl being refitted for civilian life. Having spent a lot of time on these boats when I was in the Teams, I can say he'll be very happy with the ride once she's back on the water. What manufacturer made the hull? Two companies come to mind. Just remind you buddy, these are HEAVY hulls, that were ment to work,and take a LOT of abuse. It takes some hp to make them run.




Darrell.

I love the look!

Have the engines been on a dyno? That would be a good place to get a feel for the torque curve of this combination. I currently have two Gale Banks Twin Turbo sets similar to those in the pics and am trying to decide if I want to try then on a pair of 502 MPIs. It sounds like a fun project but I am not sure about a reliable calibration with with the processors I have or MEFI 4s. Keep us up to date on this project.
Thanks.