Gasohol air/fuel ratio for max power

dave_85 · 01-26-2005, 11:22 AM

If I am running 10% gasohol ( that’s all they sell here ) what air fuel ratio should I tune for max power. At .85 lambda the air/fuel ratio for gas is 12.5 but alcohol is only 5.4 so 12.5*.9 +5.4*.10 = 11.79 for gasohol. Does this make sense?

Rohn · 01-26-2005, 03:23 PM

i was of opinion that ethanol blended gas ran leaner but recently it was expained to me just the opposite, runs rich. this was posted on innovate site. my WB shows about 14.7 in CL with alcohol blended fuels. only thing i run(93 octane).

dave_85 · 01-26-2005, 04:18 PM

I found the post on the Innovate site. I think I get it now. The wideband o2 sensor is really a lambda meter. The A/F ratio is calibrated to show what A/F ratio pure gasoline would give you. When I plot lambda and A/F ratio it is the same except for different scales. So as
long as I tune for a lambda value then I am OK.