[bcrdukes]

I can't say for sure nor do I have any empirical evidence to back up this claim but ever since switching over to Shell 91 from Chevron 94, my motor is quieter and seems to run smoother. The audible "ping" when I used Chevron 94 isn't obvious anymore using Shell 91. Smoother throttle response for sure but having said that, it could be the warmer weather.

Again, I have no data to back up this claim. This is just what I've noticed and it was a very obvious change since switching over to Shell 91 for a month.

For reference, this is on a 1998 BMW M3 (3.2L inline 6 Dinan Stage 1 DME tune with 154,xxx miles.) Compression was measured in November of 2011 with excellent results across all 6 cylinders. (200-210 across the board.)