There are plenty of opinions on that one. I have searched through many sources and have come up with this. The normal industry tests that are done to determine octane really don't relate to real world situations when it comes to methanol. Most books will state 89 MON and 109 RON. My experience has taught me that it is closer to 125 to 130 (R+M)/2. Keep in mind that under differing operating conditions the octane rating can change with methanol. An engine that is optimized for the use of methanol and with an A/F ratio that takes advantage of methanol's cooling effect can stave off preignition very well indeed.
Blown alcohol racer's typically run 10 to 12 to one CR at high boost levels. It takes a lot of octane to do that. In my experience, I have run for short periods, up to 26 psi with a 11.27 to one static CR. If you calculate the dynamic CR it comes out to something ungodly like low 30s to one. If you can keep the genie in the bottle, methanol is a fantastic fuel.
