Originally Posted by Mike Benvo
It depends on the conditions. Depends if the car is achieving its targets on 91 or if it's pulling back ignition.
Some customers request a higher octane tune for when race gas is used.
As I recall my car was retarding significantly on 91. I probably could have stuck with a stock, so called 91-based tune but went with a 93 octane (I don't think 94) version because I now regular blend Sunoco or VP Racing 100 with regular pump 91. I suppose during our current cold weather the performance would have come through even with 91 octane. The good news is that come this summer I should still get comparable performance.
It's a challenge to not bounce off the rev limiter. The nice thing is that doing so is not brutal, just annoying.
2010 BMW M3 Coupe M-DCT w/Tech-EDC, BMW M Performance Exhaust, BPM: Stage I / Euro MDM / DCT / Steering, Space Gray / Fox Red Extended, and a Trunk Monkey known as "Der Stig", plus the daily driver...
2011 BMW 135i M Sport DCT, w/BMW Performance Power Kit, Exhaust, and Brake Rotors, Space Gray / Coral Red, known as "Stiggie" with an outlaw F20 "M135i" badge.