Hey yall, back again to bug you guys about my noobness to carb tuning lol.
So the truck is now broken in, engines nice and happy, although my carb setup is transferred over from my old cam and it was tuned in the Appalachian mountain region. I have since moved to Williamsburg VA, where instead of being 2000 feet above sea level I’m 20 feet above, and I’m definitely noticing the difference with the way the truck runs.
Currently the idle is super rich, hot idle afr is around 11.5ish, cruise is super lean, mid to high 15s, sometimes even into the 16s (45-50mph) under 2000rpm.
If I setup the idle screws to be for best vacuum, then 1/8 backed off, it idles at about 13.5ish afr, but the cruise is again stupid lean.
While driving, blipping the throttle it reacts very strong. Crisp, instant response, and I can see the AFR gauge dip rich as it reads the pump squirt, so I know that the accelerator pump is setup well enough, but if I roll into the throttle semi-slowly it has a flat spot, lean then the mains catch up and it fires off.
I’m thinking right now that I need to make the idle feed restrictor smaller, and enlarge the TSR, because if I have learned anything (correct me if I’m wrong), cruise and rolling into the throttle being lean is a transition circuit issue. My thought is that I can make the IFR smaller to let the idle pull less fuel and have the idle screws more “out”, and the TSR is able to pull more fuel when it needs it.
As it sits, the carb is about 7/8 turn out on all 4 corners, 6.5PV, .047” PVCR, .028” IFR, .028” emulsions (middle of 3 blocked), .078” TSR, .070 IAB, .028” MAB, 65PMJ, 73SMJ. 24” idle vacuum, ~20” cruise vacuum, 20° initial timing on ported advance