that's rookie numbers you have to pump this numbers up. My S550 usually run 240F CHT when it's running. It vorries me a bit but never was governing itself just minor pull in timing. Also A/C off/on doesn't matter I leave the air on but turn the A/C off (only started doing that at 400 or so laps though). The S550 base will need a bigger radiator to coop with track driving.I was just at a Chin Weekend at Sebring. Temps outside were around 85F. I was running the A/C while sitting on the grid just to be comfortable. Forgot to turn it off. Once on the track maybe 5 laps into the session, the engine started governing itself at around 5000 rpm. I was at WOT and when it hit 5000 RPM it just cut the power and barely accelerated further. No warning lights, all gauges were normal , cylinder head temp was showing 217F. I was like “WTF”!.