View Single Post
      01-15-2013, 12:19 AM   #21
///M Rakete
Rocket Scientist
///M Rakete's Avatar

Drives: BMW 2015 M5 Competition
Join Date: Aug 2009
Location: Utah

iTrader: (4)

Originally Posted by Mike Benvo View Post
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.
2015 BMW M5 Sedan Returned to BMW at end of lease.