Hondata

In California where I live, we run 15% ethanol in our gas year round.
The stoichomteric ratio for E15 gas appears to be 14.04.

Any recommendations for using this as the target closed loop AFR versus 14.7?

More specifically, is there any risk from running too lean at 14.7 while using E15 gas?

Thanks.

We have not seen any problems running 14.7 using California fuel.

Remember that the lambda sensors in the vehicles (and aftermarket) read from stoichomteric and then convert to AFR. The conversions are always for straight gasoline.

So if your vehicle shows 14.7:1 on E15, it is actually showing that the exhaust lambda is 1.0, and with E15 you are at 14.04:1 or whatever E15 stoichomteric is on that day.

If we all just used the equivalence ratio than it would be much simpler.

BTW I've yet to see over 10% ethanol in California. There was a proposal last year from EPA to CARB to allow E15 year round, but I'm not sure the law has changed yet.