most Traxxas engines like to run in the 180-190 range now this is what i've seen recommended to many people, BUT here is the kicker....those temps are with Blue Thunder Fuel, if you are using Trinity (Which is a good fuel) the motor is going to run much cooler (i've seen as low as 145) and i have found that the Traxxas motors run better with the Traxxas or Blue Thunder fuel with a little heat in them.