Premium Octane?

[2wheelsforme]

Have to disagree here. I use mostly 87 and get the standard 40-42. We have a place here that still sells "91 ethanol free", when I use that I get 43-45 mpg. I believe it also runs a little smoother on take offs. During this years rally, when we were in CO, we were getting 50 on some runs, but drop some elevation and get into Kansas, the mpg's dropped into the 30's

Talking about octane, not ethanol vrs pure gas. I agree pure gas what we call here marine gas is better, and much more expensive. Two other things that affect the possibility of pre-ignition are timing advanced motors and high altitude. In other words it is the pure gas causing your better mileage not the octane. I also got better gas mileage while in high altitudes' this summer.