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


Hi Paul;
Here are some really poor old photos.
I'll try to dig up the BOM and construction notes again...
Cheers
Cary

Thanks Cary.
The torque peak is obviously way down there :)
Great work.

Paul Lamar