campindog
07-29-2012, 01:44 PM
Is there a right/wrong way to do this?
Do the transfer slots in the secondaries of a vacuum secondary carb actually work prior to the secondary boosters kicking in?
I'm having a heck of a time getting a quickfuel hot rod series carb (680 v/s) to idle decently. I have a stockish cam in a mild 331. I've messed with both the IAB and IFRs without success. The idle circuit was waaaaay too rich out of the box. I had to keep the the idle mixture screws ~1/4 turn out. It would die with a little more or a little less. Very touchy! I opened the idle bleeds from .70-78-.83 and it's better, but still runs like crap. Then I shrunk the IFRs from .028 to .026 and brought the IAB down to .63. It idles better but tip in sputtered and fell on it's face. Not drivable. Back to .028 IFR's with .83 idle bleeds. I closed the secondary mixture screws, and put duct tape over the idle bleeds. Best yet. I was able to turn the primary mixture screws out ~1 turn and drive the car. Idle is ~14:1 AFR @ 16"Hg. Cruise is ~14-15 AFR @ 19". With the PV open <8.5" AFR goes to ~12.5. The transfer curcuit however is real lean. About 17:1 at 1500 rpm. I think next I'll try shinking the idle bleeds back to .78, leave the scondary idle circuit off and try again. I haven't done anything with the secondaries yet.
Am I on the right path?
Do the transfer slots in the secondaries of a vacuum secondary carb actually work prior to the secondary boosters kicking in?
I'm having a heck of a time getting a quickfuel hot rod series carb (680 v/s) to idle decently. I have a stockish cam in a mild 331. I've messed with both the IAB and IFRs without success. The idle circuit was waaaaay too rich out of the box. I had to keep the the idle mixture screws ~1/4 turn out. It would die with a little more or a little less. Very touchy! I opened the idle bleeds from .70-78-.83 and it's better, but still runs like crap. Then I shrunk the IFRs from .028 to .026 and brought the IAB down to .63. It idles better but tip in sputtered and fell on it's face. Not drivable. Back to .028 IFR's with .83 idle bleeds. I closed the secondary mixture screws, and put duct tape over the idle bleeds. Best yet. I was able to turn the primary mixture screws out ~1 turn and drive the car. Idle is ~14:1 AFR @ 16"Hg. Cruise is ~14-15 AFR @ 19". With the PV open <8.5" AFR goes to ~12.5. The transfer curcuit however is real lean. About 17:1 at 1500 rpm. I think next I'll try shinking the idle bleeds back to .78, leave the scondary idle circuit off and try again. I haven't done anything with the secondaries yet.
Am I on the right path?