my 500 detonated on Sunoco 110, my compression is sett up low, has around 152psi cranking comp with me kickin. it also has to do with how well your engine flows, if u have a good port pipe combo u can still detonate your engine with low compression and the squish being perfect.. im in a pissing match with the dealer of the 110 right now, I believe he cuts it with lower octane fuel