I know and we've discussed that automotive turbos are undersized and tend to
overspeed when pushed to full power levels for any length of time.  The
obvious remedy is to replace the oem unit with a larger turbo.

I wonder if an automotive-type oem turbo would work well if plumbed to only
one rotor housing (actually a twin turbo arrangement)?  Im guessing that
that might have the same result of plumbing a single larger turbo to two or
more rotor exhaust ports.

I know you have mentioned this before, 1.) what is the expected rpm of a
turbo, and 2) In a turbocompounded application, why can't a turbo be
directly geared to the crankshaft to limit its overspeeding)?  3) Do you
think it feasible to somehow drive a waterpump with a turbocharger (related
to the marine jet drive application) as a way to turbocompound?



A TO4 seems to work OK. Weighs 16 pounds less a waste gate.

I suspect the ones that are failing are going over 100K.
My guess is you want to keep it under 80K.

Yes a turbo can be directly geared to limit its over speed.

Yes but you would need a 300 HP engine to get 50 HP for
the water pump. I think you mean the pump in addition to
a prop. That might work. How about an air compressor and a
cushion of air bubbles under the hull?

Paul Lamar


I was thinking along the lines that a turbo driven waterpump might act as an
extra precompression stage, to add pressure/volume to the water normally
drawn into the WaterJet pump (by vacuum?) from under the boat.  Just ideas
to increase efficiency/volume of the mass (thrust) exiting the nozzle.

The water bubble suggestion is interesting- a productive way to use any
unwanted overboost pressure/air volume to the intake.

The engine is a Renesis- I like the idea of using a turbocharger, mostly to
muffle noise, but also like the increase power, torque, and overall
efficiency.

Mike Parker