mixture has absolutely ZERO affect on CHT
Cranked up the 210 the other day for YMEN. Cracked open the cowl flaps a couple of notches in the cruise to bring the CHT’s back a bit. After 5 minutes the CHT had come back about half a needle width on the gauge.
If I tweak the red knob and run the 520 at 70° LOP (using the old single probe Alcor EGT gauge, no fancy, fandangled engine monitor here), the needle moves back a full quarter scale deflection. A bit more dramatic than the half a needle width I get when fiddling with the cowl flaps.