Hello, I'm a new owner of a '78 201. One question that I can't seem to resolve is what the actual acceptable range for CHT is. Although red line is at 475F, I've read plenty of people panicking when CHTs cross 400F or even 380F. So to get a better idea of what CHT is too high, I would like to know at what CHT (on hottest cylinder) in cruise would you begin opening cowl flaps?
While #1 and #2 cylinders seem to stay around 330, #3 is typically higher toward 360 and #4 is consistently higher at 370-400F. I'm using an EDM-700. Any suggestions? Is it typical to see higher CHTs on the back cylinders?
What's better? 75% power with cowl flaps partially open or 65% power (which results in less heat) and cowl flaps closed? Or is it ok to let the CHT get to around 400 so that Cowl flaps can be kept closed at 75%? Thanks for your help with all my questions.