I can recall when I got tuned for my mods, I was using Chevron 93 octane which doesn't contain ethanol, however about a week ago I was running on vapors and stopped by a Shell gas station which has a note stating the it contains up to 10% ethanol by volume and decided to fill her up with it. The car now runs much smoother and feels like it makes a bit more torque from what I can remember than running Chevron. I did notice a slight decrease in gas mileage and now my Walbro does have a slight whine whereas before it was completely silent (gas could have nothing to do with it but just making an observation). I think I may go back to straight gasoline and just see if my mind is playing tricks on me.

 

It depends on how it's mixed really ... shell claims that they octane is measured after the Ethanol is mixed in, so there would be technically no benefits and only the downside of lower mileage.

However, I've seen more knock resistance with BP E10 than with Shell. this leads me to believe that maybe BP adds the Ethanol after the 93 octane has been measured, or that they aren't as precise on their measurements and bump the octane unintentionally.

I haven't seen any big gains from it though ... just lower mileage.

 

I fill up with Shell V-Power whenever possible. They may be slightly more expensive, but they have much better cleaners in the fuel. Check it out!

http://www.shell.us/home/content/usa...bout_tabs.html