So should you tune e-10 stoich for the same as "gas" to 14.68 AFR? I am tuning my Tahoe and since its flexfuel capable it has a ethanol sensor in the tank. No matter what I did I couldn't get the AFR to read 14.7 on my wideband, all I got was 13.8.
I remembered our gas is e-10 (90% gas 10% ethanol) and after some fooling around I found the stoich table in HP tuners has a linear scale from 100% gas to 100% ethanol and low and behold e-10 was right around 13.8 AFR I set e-10 for ~ 14.6 AFR and voila! worked perfectly. After cruising for about 60 miles I noticed a 2 MPG gain on the tahoe.
Searching around I've found that E-10 stoich is between 14.03 and 13.9 AFR does that mean I should set the AFR on my other cars to 14.03 as well since they don't have ethanol sensors or should I leave it at 14.68 and call it a day?