Tracy told me he is going to try the automatic TX low power RX8
engine. I think Bruce Turrentine has talked him into it :)

IMHO I think Tracy and Bruce are making a mistake.
Here are the torque curves for both the high power and the low
power RX8 engines. As you can see the lower power engine makes
more torque and HP at 3000 to 5200 RPM. Not what we need.
Particularly with a 2.85 to one gear box. What we need is more
torque and consequently more horse power 7200 RPM and up provided
by the high power version.

He intends to port the engine so that will help. However porting the
high power RX8 engine will also help relatively the same amount.

Long term however, with a smaller prop diameter than the 74 inch he is
now running,  the RPM could be increased to 8500 resulting in a lot
more power for takeoff and racing. Since Tracy has been racing the last
couple of years the crowds around his airplane and at his SnF talks have
been increasing. There is nothing more cost effective in convincing pilots
of the viability of an aircraft engine as cross country air racing. We need
some more rotaries running in the SnF race. I was hoping Tom Parkes would
run his turbo three rotor Lancair ES in the race this year. Cuffs on his IVO
3 blade prop ought to get him up to 230 MPH or so.

On the up side more torque at 5000 to 6000 provided by the smaller
runners will give slightly better BSFC for cruise. Perhaps that
is what Tracy and Bruce have in mind. The ideal would be a valve to
cut out the top end ports for cruise.

Paul Lamar

I'm trying to imagine what is different between the AT and MT engines other
than manifolds and computer programming.  Are the rotors different--i.e.
different compression?  Surely the end plates (and ports) are the same,
otherwise there would be two production lines.

Mike McGee, RV-4 N996RV, O320-E2G, Hillsboro, OR
13B in gestation mode, RD-1C, EC-2

The Automatic low power is a four intake port engine and the manual high power 
is a six intake port engine. Here are some shots of the RX8 automatic end housing. 
You can see the missing ports.


Paul Lamar
 
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