Marko wrote: > You want to run the lowest ocatane you can without pre detonation. The additives for high octane are intended to make it not burn well and will reduce power. It's done for high compression, as that and whatever else is going on needs not to pre detonate. E85 burns so poorly but for boost or high compression is the bomb. Yep, it's exactly what Marko says here, (and it's quite refreshing to see someone who actually knows what they are talking about ;-) P.S: 'pre detonation' is what 'muricans call 'pinging' -- peer .