442 Quad Turbo
09-19-2003, 02:55 PM
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09-19-2003, 09:20 PM
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Tom Earhart has a TT 454 Eliminator, runs in the 130's. Turbos in a marina app do make a bit more sense. Turbos dont make their power until 3500 or so RPM, which is where the boat is normally at, or higher. Plus, you dont have a ton of drive blowing torque at low RPM like a supercharger. You do have to run open engine compartment, due to the heat, and Im pretty sure it is a law in most states for the BOV/Wastegate, having to be in an open area.
09-20-2003, 03:26 AM
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Originally posted by CAP071
Turbo's = Heat I'm not sure have they ever run turbo's on marine apps? in a high rpm motor where they hold rpm's up for a long run.
Turbo's = Heat I'm not sure have they ever run turbo's on marine apps? in a high rpm motor where they hold rpm's up for a long run.
09-20-2003, 08:12 AM
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The motor is real neat....but kind of experimental too.
Then again a drag race motor only goes 1/4 mile at a time at WFOT. Not like a boat that sustains the length for maybe 20-30 minutes or more.
Not knocking it, it is "single purpose" built.
Then again a drag race motor only goes 1/4 mile at a time at WFOT. Not like a boat that sustains the length for maybe 20-30 minutes or more.
Not knocking it, it is "single purpose" built.
09-20-2003, 12:21 PM
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Got boost?
Looks like the pop-offs are closed systems on the enclosed engine compartments.
Since turbos don't rely on engine RPM to spool up boost (like blowers), the old notion of low-end loss is pretty much out the window (engine load will dictate boost).
Newer turbos spool up very quickly with less turbo lag than the old days (a guy on the other board gets 20+ lbs in less than 1.5 seconds).
Since turbos don't rely on engine RPM to spool up boost (like blowers), the old notion of low-end loss is pretty much out the window (engine load will dictate boost).
Newer turbos spool up very quickly with less turbo lag than the old days (a guy on the other board gets 20+ lbs in less than 1.5 seconds).
09-21-2003, 06:38 PM
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Most turbo boats I have seen have used the automotive housings. These days, they have water-jacketed housings for marine applications that help a bit.
Problem is, that you want to keep the exhaust as hot as possible until it exits the turbine housing. If you cool it, it loses energy.
That's why those high-tech ski racer motors use little shorty exhaust manifolds that mount the turbo as close to the exhaust ports as possible.
I knew a guy who ran turbos on a hardcore recreational offshore boat with good results. He ran a blowthru setup and used a solenoid-controlled popoff valve on the carb boxes that vented back in front of the compressor turbine. He hooked a switch to the sticks so that the valve stayed open until 3/4 throttle. He would have to be careful coming out of the hole cause if you slowly advanced the sticks, the turbines would spin up with no load and when you got the sticks to 3/4, the valves would slam closed and you'd have full boost all of a sudden. The best way out of the hole was to either STAY below 3/4 stick and let it take forever, OR go ahead and give her 3/4 stick and come on out HARD. Once at speed, however, pulling back on the sticks when the boat cleared the water, you'd have full boost when you reentered cause the turbines never slowed down with no work being done when the sticks came back.
He did blow a few TRS trannys with that setup though. That transition from no boost to ALL boost was pretty aggressive.
Problem is, that you want to keep the exhaust as hot as possible until it exits the turbine housing. If you cool it, it loses energy.
That's why those high-tech ski racer motors use little shorty exhaust manifolds that mount the turbo as close to the exhaust ports as possible.
I knew a guy who ran turbos on a hardcore recreational offshore boat with good results. He ran a blowthru setup and used a solenoid-controlled popoff valve on the carb boxes that vented back in front of the compressor turbine. He hooked a switch to the sticks so that the valve stayed open until 3/4 throttle. He would have to be careful coming out of the hole cause if you slowly advanced the sticks, the turbines would spin up with no load and when you got the sticks to 3/4, the valves would slam closed and you'd have full boost all of a sudden. The best way out of the hole was to either STAY below 3/4 stick and let it take forever, OR go ahead and give her 3/4 stick and come on out HARD. Once at speed, however, pulling back on the sticks when the boat cleared the water, you'd have full boost when you reentered cause the turbines never slowed down with no work being done when the sticks came back.
He did blow a few TRS trannys with that setup though. That transition from no boost to ALL boost was pretty aggressive.
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