They were designed to use FAI fuel(no nitro) in Europe. I run no more than 5% in mine. Same way in my MVVS. When I bought it they said no more than 10% or the piston would self destruct. More is not always better. Power-Yes Nitro- No It would be like putting racing gas in your lawnmower, wasting money, creating a little more power but shorting life span. If you need to run a large amount of nitro to make engine do what you want it to, Buy a larger engine. These engines will last forever almost, if we don't abuse them. The way I look at it- Running high rates of nitro is almost like getting that last 3-400 rpm when we tweak our motors. We think we need the extra power till we get in the air, turns lean, gets hot, hurts motor. So much for extra power. All motors run on a simple formula- more fuel- more rpm- more heat-more money. I've raced alots of things, I thing I've found out- Speed and power cost money. Looks like I gave more than my 2 cents worth.