I'll still take a 65% nitro engine with open exhaust over a piped engine on FAI fuel. Better torque, wider rpm range, better fumes during start, and a much better song in the air. When guys were racing the same airframe with both nitro engines and piped engines, nitro was always faster.

Engines make power based on a lot of factors, and one of those factor is the mass of the air/fuel mix. Nitro weighs more than methanol, and runs a much wetter mix. Where you might run an oz. a minute with low nitro/no nitro fuel in a 40, with 65% nitro you will flow at 3 oz. a minute.

Of course now with plugs costing 10 to 20 times the 50 cents we used to pay...........that one flight per plug would certainly hurt. But if you stay with mild sport fuel (40% and lower) you might not kill the plug if the head is not screwed down too tight..