Originally Posted by Mystikal
That actually doesn't make much sense, unless the motor was so highly tuned that it detonates on anything less than 94 (which would have to be a seriously aggressive map/compression ratio). The Sunoco 94 is 10% ethanol (as well as the 91 in most other stations) while the Shell 91 has none. This tells you right away that the Shell 91 will be more efficient.
And for the record, I did the same test in back to back tanks in my M3. The Shell 91 consistently averaged around 50km more per tank than Sunoco 94.
yea i realize that but I still ended up getting about 25 more kilometers out of the sunoco 94....i run shell 91 whenever I can. It has proven to be the most cost effective fuel for my car.