Hi
 Do you have a HP / RPM graph for a 13B engine.

 Paul M

 Stock side port or or P-port?

 Here is an early 13B of around 1989 and some others.
 Note the 800 HP drag engine is running on Alcohol
 and can drive a 2000 pound car to 153 MPH in the
 quarter in less than 8.66 seconds.
 The engine is VERY ROBUST. That is about 4 HP
 per pound of engine weight.

 Paul Lamar


Paul,
Looking at your Mazdatrix dyno, the power drops off considerably as the RPM
drops from the 7000 range to 5000. 5000 would be a bit low for cruise but even
6000 is down a lot. What do you attribute the drop to; intake length, exhaust
tuning? Boing Boing engines can have a dip when cam, heads and manifolding do
not match up.

Dale Davies

This is what you will get with a highly tuned engine.
The RX8 has a very complicated intake system to tune
the engine over a wide RPM band. You don't need it in
an aircraft engine. Cruise at the 6000 RPM torque peak
for lowest BSFC.

6000 RPM is the sweet spot in a Mazda engine as that is where
the bearing loads are lowest.

Lets say one is real cheap and one wants it all including max power
on the top end. One has a constant speed prop and wants to run the
engine at only 4000 RPM and fly the airplane in the bottom of the
drag bucket around 140 MPH to maximize the MPG.

Then implement this.

I think Cary built an engine like this but I lost the pictures.
Cary can you send those pictures again?

Paul Lamar