I am slowly coming to the conclusion that we don't need a
waste gate if you
use a TO4. Greg Richter and Dave Garber are both getting away
with out waste
gates. This I think has to do with several factors.

One: the rotary will tolerate
a lot more boost than Greg is asking of it. In Dave's case it
is just plain
remarkable as he is looking at 55 inches of Hg manifold pressure.

Second: if you use a large enough turbine with a small enough
compressor
the system will limit the boost on its own. Now I am not sure
what the critical
altitude will be however and I sure don't know what those
part numbers are
right at the moment.

Three: waste gates are necessary in cars because you want the
turbine to spin
up quickly when you nail it. That is not so important in an
aircraft engine.

Fourth: since Chrissi's HKS manifold waste gate branch goes
off towards the flywheel
end it seems like it will interfere with the motor mount in that area.
A possible solution is to move the motor mount outboard and
use a large
hole in the motor plate to pass the waste gate branch through
if a waste gate
is required. The starter wants to occupy this area as well.

Fifth: Greg's HKS manifold seems to be more suitable for
aircraft use as the
waste gate branch is much shorter and much closer to the
manifold proper. Is
Greg's the 88-91 HKS version?

I sure hope the stock turbo works as it seems to solve many of these
problems with its built in waste gate.

Paul Lamar

My factory stock 1966 Corvair Corsa turbo has no wastegate. Boost is limited
by small carburetor and exhaust backpressure restriction. A lot more boost
can be had if mods are done like bigger carb. In an airplane I think you
could manually limit boost with throttle if you keep an eye on manifold
pressure. I agree, with careful turbo selection you should not need a
wastegate.

Chuck Dunlap

 
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