Ethanol question..

E10 is fine. Most cars made in the last 20 years handle it just fine.

I live on the fringe of a mandated E10 area, so I have access to both types of fuel. I will patronize the station outside the area that claims to be ethanol free and the mileage is better in our Hyundai. I also make sure to go out there for the last tank before winter storage of the Mustang. I don't drive the Mustang enough to keep track (a full tank will last a month or more).

Over the last 5 years of observation, it's making 1-2mpg difference in our Hyundai. It may not be that much for other cars, but it's something I keep track of.
 
The thing I am concerned about is my car isn't stock.. I have all the mods in my sig, and am close to the limits of my shortblock. THATS why I am concerned- obviously if my car was stock I wouldnt care much about the E10 sticker on the side of the pump.

I will ask Tim @ MPH and see what he says...
 
yep most true

read all the posts some correct you get less MPG but you can run the low octane stuff in high compression cars that call for high octane ? I have seen it done & there is no pinging yes I know the computer makes adjustments but all in the 10% is not all that bad & if your in a place where the temp drops down to O in the winter the stuff will help the car start , but no doubt about it you will lose 1-2 MPG ...
 
Right the stoichiometry is changed, but i dunno what you mean "messes up". If you're pulling a lot of timing and are tuned on regular gas then it's something to look into how it effects your tune, but the gas itself is not going to be prone to detonation.



by messes up, i mean changes. by my quick calculations, (may not be perfect) you'd be at 14.1 instead of 14.7 with E10 at idle.
 
Yes, the stoich ratio changes, but the lamda you want to shoot for does not. Your O2 sensor measures lamda and will continue to shoot for a stoch ratio at idle. In truth, the air fuel ratio does not matter and only gives you an idea of what you are looking at. Lamda is the important number and will not change.

by messes up, i mean changes. by my quick calculations, (may not be perfect) you'd be at 14.1 instead of 14.7 with E10 at idle.