I know I should/need get retuned for the new blend of Ethanol gas,
which was mandated by the Feds, back in May..

My question is: My car was tuned with 11.xx AFR back when the gas
was just regular gas with out the ethanol.

Fast forward to today.. Since ethanol is less effectives(less bang for buck).
Im concerned about Detonating when on boost.

With same tune and ethanol mix.. Does it lean out the AFR's?? or does
it go the other way??

thanks

 

From what I've read on this forum, there's been ethanol in gas for a long time. The federal mandate should not affect your tune.

 

If you are tuned for ethanol free gas, and you put in ethanol blended gas, you will run leaner (how much depends on how much ethanol is present).

You should retune your car for the ethanol blended gas, for the same lambda value as you did before. The easiest to do is to just plug in a wideband sensor that is configured for normal gasoline AFR scale, and then tune to the same AFR as you would normally on pure gasoline.

The ethanol will enhance the fuel's anti-detonation characteristics.

 

https://www.rx7club.com/showthread.p...hlight=ethanol