Originally Posted by Len Todd

I put telemetry in all my gas planes. My first plane (existing and later put in telemetry) was running over 300 degrees F and I was able to get that down to 230 with baffles and more air outlets. Most of mine run about 225 - 250 give or take ambient air temps. Also, I use the telemetry RPM readings in the air to figure the best prop that gets the engine in the power band. There is quite a bit of difference between running on the ground and in the air. RPMs also help tune for that slightly rich sweet spot. But you can get a hand tach too for that.