Posted for John Hafen
<j.hafen@comcast.net>:
Fred: Many thanks for this great information. Extracting a few summary
points: * Factory recommended setting is 50F rich of peak for many engines. This turns out to be the worst
place to operate for many engines, particularly at high power settings. * The hottest CHT occurs at the point where EGT is about 50F
rich of peak. * We could lean a lot and only lose a little power. * If we lean to max CHT, wešll have max power for that MP/RPM
setting. So if a guy looks at the factory recommended setting of 50F rich of peak, and that historically gas has been
pretty cheap, one wonders if the 50F ROP recommended by the factory was simply to extract maximum power out of the engine at the
expense of gas and cooking the engine in the process (at max CHT for max power). So you go a little faster (perhaps) at the
expense of gas and the longevity of the engine. And I doubt, like you say, the factory will ever change
their recommendations, opening them łto criticism that past advice may be wrong.˛ Thanks for the John Deakin Pelican Perch
site. Most excellent. John Hafen IVP N413AJ 101 hours (would be more if I didnšt live in
Seattle!)
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