Doug wrote:

Ok, here is a question for anyone on the list with Turbo experience.
I have a buddy flying a KR-2 with a 1835cc VW air cooled opposed engine.
He has been running it turbo'd for about 8 years. He is a propulsion
engineer and he has
a very interesting way of setting up the turbo. He, is using his turbo
that he salvaged from a large displacement truck motor. He isnt sure of
specs because he has never taken it off since he bolted it up to
experiment with. LOL, Sort of like Tracy with the "looks about right"
A/C evaporator theory. Here is the magic. He chose to run his air fuel
mixture through his turbo then into his intake system. With out any
scientific data he has noted that his intake charge temperatures are
amazingly low and that he chose not to put an intercooler on there for
weight and he chose not to use a wastegate or blow off valve. He has
told me that he uses 42 inches to keep up with the RV-8 w/IO-360 200hp.

Now with my experience of flying turbo charged airplanes, a blow off
valve is not neccessary. I also believe that a wastegate is not
necessary as long as you fly manifold pressure for measuring  power. My
turbo has a large A/R ratio of 1.3. That is necessary for normalizing
pressure. It slows turbo speed down but increases density when density
altitude is high. 

My only concern and the reason for bringing this up is
about the intake mixture being introduced prior to the turbo. I know
that the old turbo set ups in race cars, a long time ago, used to go and
take turbo air and pressurize a carburator. But I have never seen
anybody take the fuel and air through the turbo. Has anyone else? The
only problem I see is density of mixture to be less when the turbo
demand is high which creates more heat. He cannot go out and feel the
intake runners in flight! I cant get him to  go and buy a monitor for
real data. But his system is working. 

Does anybody else see a problem
whether a rotary would have any problems with this type of set up?It
would sure get rid of some more weight! He is now building a RV-9 and is
planning on doing the same thing to the 13B for that airplane. He is a
ways out from completion as he just got his empanage on Fri. but he has
been hovering around my 13BT in the RX-6....LOL
Thanks for the listen, Doug

 
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