93 Octane + 10% Ethanol vs 91 0% Ethanol

[rweidman]

I have been burning 93+Ethanol lately and seem to get a little more seat of the pants torque than my usual 91 0% Ethanol. My gas mileage has dropped about 2-3mpg with the 93 ethanol mix though. It is about 10-15 cents less per gallon than the 91 no ethanol. I am running a Stage 1 Cobb tune with a Cobb air filter. Think it would pay to go to 93 tune without any other engine mods. The extra mileage is nice with the 91 no ethanol, but may just keep burning the 93 ethanol and retune. Any suggestions.

 

[COBB Tuning1]

In our experience, 10% ethanol fuel provides a performance benefit over 0% pure gas. If it was me, I'd run the 93E10 fuel and 93 OTS map all day long!

Ian

 

[rweidman]

Thank you Ian. As soon as I can trust spring, get my summer tires on, I will reprogram and see what shakes.

 

[scenicroadways]

Great question/response. I am also from WI, and we have the 93E10 all over the place near Milwaukee, but when headed up north its 91 no ethanol everywhere.

 

[FORZDA 2]

In our experience, 10% ethanol fuel provides a performance benefit over 0% pure gas. If it was me, I'd run the 93E10 fuel and 93 OTS map all day long!

Ian

This matches my experience as well. I ran their "Premium" (LOL) 91 pure gas in Oklahoma and it is terrible for forced induction. I had to keep the boost way down to prevent knock on the OTS Stage 3/91 baseline map. I'm back in VA now with very good 93+10% and I have switched to the Stage 3/93 baseline map and the ECU keeps adding timing even running the boost at 28psi!

 

[Gar Woods]

any opinions on stock ST with either 91 pure or 93 with 10%