I've been tuning Evos on pump fuel for years now with the ocasional use of racing fuels such as VP C16, but I never did an ethanol tune before, next week will be my first Ethanol tune using E100 on an AutoX Evo, SD rom. Knowing that Ethanol has a different stoichiometric AFR than pump fuel I'll start the tune with decreasing injector scaling by 30%. I'll be logging AFR through my old trusted Innovate LM-1 reader. Since the reader is normally set for gasoline at 14.7, I'm assuming that I should tune fuel similar to gasoline tune, 12.5 during spool up and around 11.8-11.5 max boost through red line. Perhaps I would even try more aggressive AFR like 11.7-11.8 by red line.

Am I correct in assuming that my Ethanol AFR target numbers should be similar to pump fuel targets when using a 14.7/gasoline wideband reader?

 

You are correct. The sensor reads lambda and then simply applies a formula to that. So if your gauge is using the gasoline formula you can shoot for those targets.

 

E10 (pump gas) to E85 needs 30% more fuel, so E100 is probably about 36%.

The thing I'm not 100% sure of is if E85 needs 30% more fuel, which becomes 1÷1.3, which is reducing injector scaling to 76.9%. And for E100, 1÷1.36, which reduces injector scaling to 73.5%