Originally Posted by benjamin
When the engine is fully warmed up, there shouldn't be any undetonated fuel exiting the tailpipe. If there is, something else is going wrong. I don't know where you got the idea that higher octane fuel burns more completely than lower octane fuel, but it isn't true.
Then why are there race fuels and why does my race bike (and cars too) run better on the higher octane race fuels?