A good example of what Tex is saying about reading your truck, the Traxxas manual says run the 2.5 no higher than 270*, and that's pushing the high side. My 2.5 ran the best in the 280* range, before the addition of the RD Logics pipe. Good smoke, both on low and high RPM's, good bottom end torque, and good high speed. If I "Tuned to temperature", the truck would bog, spit fuel, and was near impossible to keep running. I'm not suggesting that all engines should be tuned by watching the smoke, just that is how MY 2.5 wanted to run...