I’ve used as much as 25% E85 in myZ and noticed a slight increase in response after the ECU adjusted the fuel trims. Mileage was about 1-2mpg less. I did notice from a data log that the full throttle open loop operation ran at 12.1 a/f ratio whereas 93 octane ran at 11.95. That would be expected. My Z is stock except the engine has a tune for 93 octane.
I have heard from experts in the field of engine maintenance and wear that ethanol actually burns cleaner than petroleum gasoline and has less tendency to form sludge and varnish in the crankcase. Also it has a cleaning effect on the combustion chamber. They also say that the additives in E85 prevent fuel system corrosion and deterioration in vehicles manufactured after about 2001.
|