First off, I leaned out the mixture to the 870s 880s, making sure I didnt have any KR.

My stock timing was 24-26 in some areas with 28 in the rest so Tthen moved all the cells to 28 so that I'm getting 28 across the board.

When I did this, I began to see knock retard. So I just richened up the mixture until the KR went away. I'm sitting at around 910ish across the board.

I assume that I am now as lean as I could possibly be without getting KR at my desired timing, correct? Will this be as good as I can get without a wideband?

 

Yeah. I think since the 02s are placed further downstream w/ LTs that your 910 mV reading may be the same afr as a stock manifold's car 890 reading. The exhaust cools a little more which will naturally raise the mV reading from the 02s.

 

There is no good way to tune AFR without a wideband. Period.

Ryan

 

Use the Force........

 

Did you do this by increasing multiplier by 0.01 in the PE table until you get your results ? I am planning to do exactly the same thing. I dont have the possibilty to use a WB here in germany and have to find a way to make it as good as possible with the NB Stock O2s. I will try to get the A/F mv reading to 880/890 mv as i still use my stock headers.

Thanks,

Jochen