I have not had good detonation protection using currently marketed octane boosters. Years ago there were two octane booster Moroso and Vortex that would raise the motored octane level well over 5 points. The problem with these two octane boosters was that it cost more to treat a gallon of pump gas than it cost for a gallon of race gas. I think that the EPA made them take it off of the market.
There are a lot of octane boosters that will raise the research octane level 3 or 4 points but engines do not seem to respond to increases in research numbers like they do to the increases in the motored octane numbers.
I have used thousands of gallons of 100LL Avgas over the years with two strokes with good results. I usually mix 1 gallon of premium pump gas to 4 to 5 gallons of AVgas. The pump gas insures the two stroke oil stays mixed and often will make a little more power than straight AVgas. It does not seem to matter if the pump gas is ethanol free. The small amount of ethanol gives the fuel the ability to absorb condensation and distribute the water homogeneously throughout the fuel preventing your engine from stalling or misfiring when it ingest small slugs of pure water.
