91 octane fuel
 

I know that there will be a drop in power with 91 octane fuel, but how much power is lost and will the lower octane need its own tune? Here is socal its hard to find 93 or e85 fuels. Also would octane boosters help? Thanks in advance for the help

If im not mistaken, i think John said that the 93tune will work for 91 grade. And i really doubt that the "octane booster" actually boosts octane... Check with John Viscanti. Check out http://www.ft86club.com/forums/showthread.php?t=13307