I went drag racing last night. To make a long story short, not a good night to race. Car ran slow, it was packed, only got 4 runs, all because it was the night before the "fun Ford weekend" (so lots of 10 sec mustangs, blech)

The important part, I tried some more SAFC tuning, basically trying to get more timing advance out of the computer without running too lean.

I set the SAFC to -12% at 5000 rpms, and -15% at 6000 rpms and up. In 1st and 2nd gear timing was 23-24 degrees of timing advance and O2 voltage was all over the place, going back and forth from rich to lean. The setting must ahve been right at or about stoichometric.

In third gear (being key for the drag race) timing held steady at 24 degrees advance. But, O2 voltage went from a steady 0.81 volts before 5700 rpms, after that the voltage was all over the place up until 6500 rpms. About 6500 rpms it was lean, 0.2 volts, MUCH too lean. But, interestingly, the car didn't pull the ignition timing. I guess it never saw any knock, or at least not enough for the computer to care. The car also did not make a very good run, so I'd guess those settings were not optimal.


Then, I logged the car with the SAFC setting at what I have been using for a while now, -7% at 5000 rpms, -10% at 6000 rpms and up.

In 3rd gear, the O2 voltage held steady at about 0.88 V and I got 23 degrees timing advance. The car ran better with these settings as well.

So, I think the extra 1 degree advance is not worth being so far off the proper air/fuel ratio. Keeping the car (well, with stock compression, head, mild cams, and bolt ons) at about that -10% correction on the SAFC on the top end at WOT seems to be an optimal setting.

"Tutto fa brodo."

Todd Scungio
98 RS
15.173 @ 90.70 MPH

And also a 2011 Ralliart