I agree that adding ethanol automatically reduces fuel consumption based on energy calculations. Non-ethanol combined with the higher octane would account for the increased mileage. I was wondering if the DME reprogramming that helped BMW's idle and run smoother after 10% became year round in the US, would need to be rolled back to the original version to get the most benefit from a non-oxygenated gas?

Top Tier Gasoline

Canada
Chevron Canada
Esso
Petro-Canada
Shell Canada

Top Tier site doesn't mention requiring 8% ethanol.
Also, TOP TIER gasoline can contain ethanol up to a maximum of 10% by volume. In areas where ethanol is not always used for blending, a TOP TIER gasoline that has passed all performance testing is still qualified as the additive supplier would have tested their product on the appropriate fuel.

__________________
*********************
Olympic Peninsula, WA, USA
-----------------------------------------
2005 Mini Cooper 100k, British Racing Green/Silver-Black
04/2002 4.6is 140k, Silver/Black-Alcantara *FOR SALE*
1989 325iX 270k, Diamond Black/Black
1984 318i 370k *SOLD* (First Bimmer)
Honorable Mentions: '71 2002, '87 325, '90 325ic, '92 525it, '93 325i, '94 530i