Running lean then running rich?!

[slaughterj]

Today at the dyno, I was running real lean at lower rpms, and rich at very high rpms, what could cause this? How does the whole process work?

BTW, while I don't recall how it had been running at my previous dyno trip, in case it matters, I have since added hi-flo cats and corsa exhaust...

 

[slaughterj]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Mad Gray:
I believe the stock behavior is as you describe but I guess I need to know what kind of ratios you are getting. <HR></BLOCKQUOTE>

My car's variant behavior was as compared with the other cars that ran that day...


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>I use the Roe Racing VEC1 to adjust the Air:Fuel ratio. I leaned it out a bit at WOT (12.5:1 up to 13.5:1) and added some fuel at low RPMS. This seems to improve acceleration because the car breaks loose in 1st gear with the AF adjusted and doesn't when I zero out the VEC1.
[/B]<HR></BLOCKQUOTE>

I'm interested in this, but would like to make sure there's nothing wrong in the first place, so that I'm not just treating a symptom...

 

[MES]

Do you have an A/F graph from the dyno? What is "real rich" and "real lean"? Mine was right around 12.0 - 12.5 when I had it dynoed, dyno graph below. Sorry I have no idea though what's wrong with your car, if anything.