Originally Posted by
squirlz I tuned my 12.5:1 motor on 93 with 10% ethanol, now with the convention coming up i am assuming i will not be able to easily find 93 all the way down. So does anyone know how much timing i should take off the upper end of my map? Is 5* enough? Not worried about performance while cruising but i do not want to damage the motor. I will also stay out of the upper RPMs. Anyone with experience?
Don't quote me, but I'd assume the differences between 93 and 91 are so small that I wouldn't change your driving habits very much. If it's highway, then that won't matter at all while cruising. Just maybe take it easy racing the engine before you can get 93 in the tank. But to answer your question, a decrease of 5* should be MORE than enough imo. I wouldn't even touch the tune though.
Also, I think you'll find 93 octane at the gas station you stop at more than 75% of the time. BP stations seem to have 93 more than other places. Search those out.
-G