[WardL]

Most (if not all) race fuel has some kind of alcohol in it. I wouldn't mix a race fuel with E85. When Olddog says 50% to 85%, he means 50% ethanol to 85% ethanol. Ethanol has better than 115 octane and E85 is likely better than 105 road octane. I would get rid of as much rubber in your fuel system as you can before using E85. Stainless steel would be the best fuel system material for e85.