I disagree. My 429 has 10.8:1 compression and runs through the rpm range on 93 octane with no additive and no ping whatsoever. There are many variables in different engines that can and do cause this condition. It would be incorrect to make a sweeping statement that just because an engine has a certain compression ratio, it will always ping with 93 octane.Or the octane is too low.
A 10.8:1 compression nominally requires a 98 pump octane gas. It will always ping on 93. You can fudge the octane a little with timing, etc., but not 5 octane numbers. If you could, then no one would really need premium in a new car.
Adding about 40% ethanol to 93 octane gas might be about right. Ethanol by itself is about 115 octane.