[Uncle Miltie]

My 1998 Subaru gets +2 MPG (24 v. 22) with straight gas. That’s about a 10% improvement. When I can buy real gas for a 10% or less additional cost, I do it.

It runs better on real gas too.

Ethanol sucks.

[WakeUpAndVote]

I will concur on the 10% increase in mileage.

[MRadtke]

My 2008 Mazda 6 is getting about 24 MPG right now in the winter with 87 octane gas with 10% ethanol. I found a station where I can get 89 octane non-ethanol gas, that gets me about 26 MPG. I'd use 87 octane non-ethanol if I could find it, that is the recommended octane.

The owner's manual specifically states that any alcohol in gas should be avoided, and under no circumstances should gas with more than 10% ethanol be used.