Jetting for 12aBP w/ Weber 48IDA
10-20-17, 10:55 AM
#1
Jetting for 12aBP w/ Weber 48IDA
Hey guys, looking for jetting recommendations for a 12a Bridgeport with the weber 48IDA carb.
RacingBeat has some jetting recommendations, but those are for open exhaust, which would be too rich for my exhaust setup (RB RR Header into RB muffler).
Does anyone have a setup that they like using? I want to ditch the crummy Holley I have and run the weber until I finish collecting parts for the EFI swap.
RacingBeat has some jetting recommendations, but those are for open exhaust, which would be too rich for my exhaust setup (RB RR Header into RB muffler).
Does anyone have a setup that they like using? I want to ditch the crummy Holley I have and run the weber until I finish collecting parts for the EFI swap.
Last edited by Jeezus; 10-20-17 at 10:57 AM.
10-20-17, 12:07 PM
#2
Waffles - hmmm good
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Use the RB suggestions as an upper bound then buy a few sets in smaller sizes down from there. Of course every engine, especially BP will be different. You using a wideband to tune it? You probably should.
10-21-17, 09:54 AM
#4
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jetting is tough to say, we don't know how your engine flows (ports, exhaust, etc) and we don't know you fuel pressure or what mixture you want to run.
that being said, we do have some guidelines.
for a street car, idling around 1,000rpm.
idle jet should be 60 +/- 10. i would start with what you have, and go from there.
emulsion tube should be an F7 for a 12A, F8 for a 13B, the F11 tube is for air cooled VW's. on a rotary the F11 will always be lean in the idle to main jet transition, because its the wrong part. with the F7 i can get mine so rich on the transition it stops running.
main jet, with mufflers i'm ending up around 180, depending you will be 175-210, see whats in there, if you're in that range start there, and see what it does.
air corrector; i'm in the 130-150 range. i think book value is to start with main jet -50, and my experience that will get you very close. you're using it to get the idle to main jet progression smooth.
that being said, we do have some guidelines.
for a street car, idling around 1,000rpm.
idle jet should be 60 +/- 10. i would start with what you have, and go from there.
emulsion tube should be an F7 for a 12A, F8 for a 13B, the F11 tube is for air cooled VW's. on a rotary the F11 will always be lean in the idle to main jet transition, because its the wrong part. with the F7 i can get mine so rich on the transition it stops running.
main jet, with mufflers i'm ending up around 180, depending you will be 175-210, see whats in there, if you're in that range start there, and see what it does.
air corrector; i'm in the 130-150 range. i think book value is to start with main jet -50, and my experience that will get you very close. you're using it to get the idle to main jet progression smooth.