AFR on the Throttle Stop

[B1Ken]

Originally Posted by eman588G

Just recently got a Racepak and ran S/C recently and now have some data. On the Stop my average AFR is around 10.5 and wide open average around 12.2. Question, Should the AFR on the stop be closer to my 12.2??

That seems awfully "fat" on the stop. I would think that would cause dialability problems with changing temperature. I was shocked, looking at A/F ratios with my APD carb on the stop when it showed it was about 15:1 !! I don't know how accurate that was but it had the WOT at about 13.2. That carb gave me a very flat rpm on the stop. Unfortunately, I still couldn't dial the car anyway. An APD carb. has a primary power valve, which is nice because it allows you to adjust A/F on the stop. I increased the primary jet size a bit to get the A/F ratio lower on the stop.