Actually I'd have to disagree... In ALL the tests I've ever performed, running higher nitro content ALWAYS results in a cooler engine... Your absolutely correct about needing more fuel though... Which is precisely why it runs cooler.. The more nitro in the fuel, the richer you have to run it... That means more fuel moving through your engine which means the heat is displaced quicker.. Not to mention more lubrication for the engine... The ONLY time running higher nitro content will cause you a problem is if your using an engine from across the pond.. Those UK engines aren't designed for much nitro, so they have much higher compression ratios... That can mean pre-detonation with higher nitro content... I use 30% heli fuel in all my engines and get many YEARS out of engines without so much as a new piston or sleeve... It should be pointed out however... Running an engine too lean on higher nitro could cause more problems than running an engine too lean with lesser nitro...