Rv-12iS High EGT and Coolant temps

Hi Phil,

First you are well within engine specs and I wouldn't worry about it. The thing here is there are several things that can affect temps. Things like prop pitch / max rpm in level flight at your average altitude, different engine and cowl setups ups, your air filter and air flow into the air filter, cowl air flow, different instruments, cruise rpm selection. The same aircraft from a mfg can have different readings at times. Engines can all be slightly individually different. It doesn't make them out of spec because it's different from another plane like yours. Plus you only have 35 hrs. on it and it will breakin more as you accumulate more hours. Plus sometimes people's lower numbers aren't always good and would be better off slightly higher so you can't always compare.

I agree with Roger, and I would not think twice about your coolant and oil temps. I wanted to add one thought about exhaust temperature.   Myself and several others I know flying 912iS aircraft have noticed that if we reduce the pitch on the prop toward a better climb setting, we will see increased EGTs at cruise power. With my prop pitched for 5050 on climb out I will see exhaust temps in the 1450 range at ECO cruise power settings.  If I reduce the pitch for a 5200 RPM climb out, I will then see EGTs of 1550 or even higher in ECO cruise.

When you think about this it makes sense. We cant adjust the mixture, so EGT becomes more a measure of energy being wasted out the exhaust system, whereas CHT represents work being done by the engine to spin the prop. Your coolant temps (CHT) are relatively low, so a higher exhaust temp makes sense from this perspective.  The 912iS sets mixture (injector pulse width) based on a predetermined map. It does not adjust for prop settings or EGT.  So as you unload the engine (by reducing prop pitch) the extra energy has to go somewhere, and that somewhere is out the exhaust system.  What RPM do you get at WOT takeoff climb?

Thank you both, I'm going to take a look at the prop's pitch on this airplane.  I appreciate it.