constable

Salutations. My 06 Gt 5-spd with K&N CAI, Flowmasters axle back and Predator tune is causing me some concerns. I loaded the 87 tune with 87 octane pinging like crazy at 5000-6000 RPM. So i loaded the 91 tune with 91 octane,same problem only this time there is some black soot like powder at the end of my exhaust tips. I then re-loaded the 87 tune with 91 octane no pinging but a small amount of residue on exhaust tips. I really enjoyed the 91 tune should I load the 91 tune with 93 octane gas? Any advice would he appreciated. Thanks!

jst854

you will get a better response if you post this is a different forum 05+ try that