When did we change from ron to rm2?
 

When did we change from ron to rm2?

My Pcar mentor raves of the days when he could run 106 octane in his 2.2L 1970 911t..

Was this 106 ron? and / or how does ron compare to rm2?

The R+M/2 method has been around at least since 1985, since it's mentioned in my 944 manual. Actually both systems are (it gives minimum octane requirements calculated by both methods).

If you want to run 106 octane gas in a newer car it won't hurt anything (except possibly the catylitic if it's leaded) but it won't really help anything either. Higher octane doesn't really do much other than ward off detonation due to very high c/rs, advanced timing or high boost levels.