Posted By: dodgedart416
question for anyone running dual quads - 07/10/08 11:49 PM
Do you idle with both carbs or just one? If just one which one? Thanks
question for anyone running dual quads
Posted By: RodStRace
Re: question for anyone running dual quads - 07/11/08 12:07 AM
both. They should both be open the same amount (syncronized). Even 6 packs need to have the end carbs' throttle opening and mix set.
Posted By: bobby66
Re: question for anyone running dual quads - 07/11/08 11:53 AM
I think my Street Hemi idled on the primaries of the rear carb. Everthing else was progressive. I dont remember idle screws on the front carb. Has been a long time ago, though.
Posted By: Twostick
Re: question for anyone running dual quads - 07/11/08 01:13 PM
Pretty sure the outboard carbs don't have idle circuits in them.
Dual quads USUALLY idle on one carb and I don't think it matters which one. If you have a big cam and can't get it to idle without adjusting it past the transition into the main circuit, you could then set it up to idle on BOTH carbs.
Kevin
Dual quads USUALLY idle on one carb and I don't think it matters which one. If you have a big cam and can't get it to idle without adjusting it past the transition into the main circuit, you could then set it up to idle on BOTH carbs.
Kevin
Posted By: Rug_Trucker
Re: question for anyone running dual quads - 07/11/08 01:20 PM
Posted By: cyphre666
Re: question for anyone running dual quads - 07/11/08 01:42 PM
What intake are you using ?
What carbs are you using ?
What carbs are you using ?
Posted By: CrAzYMoPaRGuY
Re: question for anyone running dual quads - 07/11/08 02:05 PM
BOTH carbs.
Posted By: Anonymous
Re: question for anyone running dual quads - 07/11/08 05:15 PM
Quote:
both. They should both be open the same amount (syncronized). Even 6 packs need to have the end carbs' throttle opening and mix set.
Not necessarily.
It depends on how you set up your linkage. What you are talking about is not the way the factory did it. For both hemi and six pack they were set up progressively. Meaning that on the hemi the front two barrels of the rear carb first then the rear two barrels of the rear carb, then the front two barrels of the front carb and finally the rear two barrels of the front carb.
Aftermarket some set them up to pull the front and rear carb in at the same time, but that was typically race only.
A factory six pack was set up to run off of the center two barrels first.
Posted By: John_Kunkel
Re: question for anyone running dual quads - 07/11/08 07:29 PM
Early factory Street Hemis had mixture screws in the front carb so you could adjust both carbs, the '70 and '71 had the recessed mixture screws preset and the screw holes were plugged. (emissions)
Even with the factory progressive linkage the early idle mixture adjustment procedure calls for adjusting the screws in both carbs.
Posted By: black64
Re: question for anyone running dual quads - 07/12/08 04:26 PM
I adjust front and rear on mine. Idles fine that way.
Posted By: mickm
Re: question for anyone running dual quads - 07/12/08 04:46 PM
it depends completely on the setup, but most will idle off of both carbs. the street hemis idle off of the primaries of the rear carb, the front carb did not even have usable idle circuits. but the intake manifold was designed for (relatively) equal distribution of the mixture at idle and low end from the rear carb alone.
the stage V manifold that i run now is not set up this way, and so needs both carbs set for idle for equal distribution to all of the cylinders.
i don't know, but i would imagine that most or all aftermarket daul quad intakes need both carbs idling.
the stage V manifold that i run now is not set up this way, and so needs both carbs set for idle for equal distribution to all of the cylinders.
i don't know, but i would imagine that most or all aftermarket daul quad intakes need both carbs idling.
Posted By: John_Kunkel
Re: question for anyone running dual quads - 07/12/08 11:44 PM
Quote:
the street hemis idle off of the primaries of the rear carb, the front carb did not even have usable idle circuits.
Not so, all Street Hemi front carbs had idle mixture screws and the accompanying circuits.
The pre-'70 FSM outlines the adjustment procedure for the front carb, '70 and '71 carbs had the front carb mixture screws pre-adjusted for emissions purposes.
Posted By: 65Coronet7165
Re: question for anyone running dual quads - 07/13/08 01:57 AM
Do you mind outlining that procedure John?? It would be of interest to me. I have the FSM for the 67 Chrysler/Imperial and of course they didn't have dual quads from the factory on those.
Posted By: hemijimbo
Re: question for anyone running dual quads - 07/13/08 02:53 AM
Quote:69 rr does not have the mixture screws in the front carb,.... it does however have an idle "speed" screw, for both f&r carbsQuote:
the street hemis idle off of the primaries of the rear carb, the front carb did not even have usable idle circuits.
Not so, all Street Hemi front carbs had idle mixture screws and the accompanying circut
Posted By: bb74swngr
Re: question for anyone running dual quads - 07/13/08 03:12 AM
My personal preference is just using the idle system on the rear. I have the CH28 with two 600s. Tried it both ways and seems to adjust and transition better with just the rear. With both idles systems being used, as the primary main system in the rear carb phases over it's idle system it may not be able to sense the front idle system as well. This is just a theory with my use and not documented as far as I know.
Russ:)
Russ:)
Posted By: John_Kunkel
Re: question for anyone running dual quads - 07/13/08 06:55 PM
Quote:
Do you mind outlining that procedure John?? It would be of interest to me. I have the FSM for the 67 Chrysler/Imperial and of course they didn't have dual quads from the factory on those.
From the '68 FSM:
Posted By: mickm
Re: question for anyone running dual quads - 07/14/08 10:29 PM
Quote:
Not so, all Street Hemi front carbs had idle mixture screws and the accompanying circuits.
hmmm.... that is a new one to me. decades decay the memory, but i specifically remember my 68 NOT having idle circuit screws on the front carbs, and i though all hemis did not.
i will have to take a look. can anyone post pictures of some front carbs?
Posted By: hemijimbo
Re: question for anyone running dual quads - 07/15/08 02:35 AM
Quote:heres my 69 h/rr 40k 1 owner untouched front carb pic note no mixing screws...Quote:
Not so, all Street Hemi front carbs had idle mixture screws and the accompanying circuits.
hmmm.... that is a new one to me. decades decay the memory, but i specifically remember my 68 NOT having idle circuit screws on the front carbs, and i though all hemis did not.
i will have to take a look. can anyone post pictures of some front carbs?
Posted By: mickm
Re: question for anyone running dual quads - 07/15/08 06:24 AM
thats what i thought. no choke and no idle mixture screws on the front carb. and from what i remember, that was 66-71...
Posted By: John_Kunkel
Re: question for anyone running dual quads - 07/15/08 09:18 PM
The page I posted above is directly from the '68 FSM and instructs to adjust the idle mixture screws on the front carb. Kinda hard to do if they're not there.
Even though there are no visible mixture screws on later years they are still there under the plugs where the screws would normally be, they are preset a specific number of turns and plugged to prevent tampering with the adjustment that would affect the emissions.