AvGas vs. Regular gas for Pawnee?

the 250HP STC for the O-540 engine does not change RPM limits or approved
propellers from the original Type Certificate Data Sheet. It does allow the
use of a different piston resulting in higher compression.

We run "straight pipes" and have noticed no difference in sound.
We also changed to the lighter weight propeller that is approved on the TCDS
And a change to the SkyTec starter.

We have noticed a difference in climb power and resulting rate of climb. It
is an E-Ticket Ride for the 1-26 pilot.. his 10knt vario is pegged all the
way. We've noticed about a 150-200ft rate of climb increase for Grob 103s
and SGS 2-33s with two on board.

BT

"Bob Korves" bkorves@winfirstDECIMALcom wrote in message
. 44...
"Frank Whiteley" wrote in
ups.com:

I should mention that since we had no autogas option on the Pawnee D
model, we went with the 250HP STC also on our spring rebuild and a new
prop. Result appears close to 100fpm better climb on same fuel burn,
or about one more tow per tach hour.

Frank


Frank,
Is the 250HP conversion louder? Higher RPM? Or, maybe just more
compression and a bigger prop?
-Bob Korves