engineermike

Messing with the a/f ratio calcs is sure to confuse anyone. The factory wb measures lambda. The external scanner converts that to an a/f ratio, assuming a particular fuel. Since lambda is actual a/f divided by stoich a/f, it doesn't care what type of fuel is being burned or what stoich is for that fuel. Cruise lambda is 1.0 whether its pure gas or e10. Your hand-held's calculated a/f is where things get confusing. I would recommend leaving them set for pure gas and assume 14.5 is stoich, because this will avoid confusion and be correct for either fuel.

Z7What

The commanded Lambda stays the same but AFR changes based off which fuel is ran.

There is a article a tuner and engine builder wrote to help understand it a little better let me see if I can find it. To help people understand it better.

Wayne

Z7What

http://www.nloc.net/vbforum/gen-2-li...know-long.html

engineermike

I'm quite familiar. I tuned my own 900+ hp turbo lt1 with a lot of supplemental methanol. My innovative wbo2 was set to pure gas so all i had to tune for was 11/1 by the gauge. Actual a/f ratio was probably closer to 9/1, but it didn't matter as long as lambda was right.

With everyone running different concoctions of gasoline, eth, and meth these days, we'd all be better off tuning by lambda.

Z7What

I understand you may know, I was just posting that link for the guys that don't understand what you were talking about.

Wayne

gillysmi

sorry been away for a bit. I get gas from mostly one station. once in a great while I get from another. maybe 1 tank of every 10.