Originally Posted by
Sport_Pilot
If you hardly notice the difference in 500 RPM then I can understand your pessimism. However to me 300 RPM is a huge difference and the only reason I would use 25% or more nitro. Engine becomes easy to tune with just 5% nitro. And the difference is greater than a .40 to .46 more like a .40 to .52. But If I had a .52 I probably would want it to perform like a .74 at times, depending on the plane and its use.
I don't know what kind of planes you fly, but if you notice a 300 rpm difference, you're a better pilot that me. (don't get a big head...that isn't saying much. HA!)