" wrote in message
ups.com...
On Apr 30, 4:17 pm, Newps wrote:
First off gas is not cheaper than cylinders so that's a dumb argument
from the get go. At 65% you want to be leaner than peak EGT or richer
than 100 ROP for best engine health. At 75% you want to be leaner than
40 LOP or richer than 180 ROP. There are other power settings with
their own combos but these are the two most used. At your stated 65%
get yourself about 15-20 LOP. That's good for the engine and the loss
of airspeed is negligible. You can go leaner but you'll start to notice
a speed loss.


Do these 65% v. 75% ROP & LOP temp limits have any relation to
compression ratio of the engine?

No, not really.

In another words, if my engine is
7:1 CR & running at 75% power, can I run at temp limits for an engine
that is 8.5:1 CR running at 65%?

Run at the temp limits defined (EGT/CHT) in your POH, where ever that fall
on the LOP graph.

http://www.avweb.com/news/pelican/182084-1.html (Plus the entire engine
series defined in the sidebar on the right).


--
Matt Barrow
Performace Homes, LLC.
Colorado Springs, CO