Moparts

throttle response - which carb has the best?

Posted By: dangina

throttle response - which carb has the best? - 12/23/12 08:02 AM

I've used the old carters on previous mopars, and quite frankly I never liked the lack or response or that 1-2 sec delay when you put down the gas. i have a edlebrock 600 cfm kicking around on an engine and i also have a holley 750 cfm double pumper, both needing a rebuild - i haven't tried out either one yet so I can't comment on performance, so I thought what is the best out there? I love the instant throttle response of fuel injected cars so i would like to get the best I can. Is it worth rebuilding the edlebrock or the holley or should I just end up selling them and getting something better. It will be going on my 383 4 speed, 3:55 gears, relativly stock build other than cam, intake and headers.

heres the catch, In about a year I'll be doing a 451 stroker, So I probably will have to upgrade anyways for the build probably an 850. I just wanna hear some opinions on your experiences with carbs...

sorry I should mention the car is a pro-touring car that is daily drivin during the spring & summer, while getting in some autox and road race when possible...
Posted By: SpareParts

Re: throttle response - which carb has the best? - 12/23/12 11:18 AM

Had a Quick Fuel 850 annular booster double pumper on my 360 once, now on my brother's stout 318. Carb is extremely responsive, previously we had it on a 437" sbc nitrous motor.
Posted By: Mr. T

Re: throttle response - which carb has the best? - 12/23/12 01:11 PM

Between the two you have, I would go with the Holley. I bracked raced for years using a 750 D.P. I finally wore it out. I am currently using a QuickFuel 680 vacuum secondary, and am very well pleased with it on my 360. I would recommend it for your use. The electronic choke would probably come in very handy on those cool Canadian days.
Posted By: 67_Satellite

Re: throttle response - which carb has the best? - 12/23/12 01:52 PM

Part of the reason such a large-for-c.i. carburetor,like that 850 on a 318, has such good throttle response is that it will allow much more air into the engine for a given pedal movement. If you press the pedal "X" amount with a small throttle blade, then try it again,the same amount with a much larger throttle blade,the larger throttle blade will drop the manifold vacuum further. Less vacuum = more cylinder pressure = more throttle response. How far the cable mounting point is from the centerline of the throttle shaft will also affect the amount of opening for a given pedal movement.
Posted By: BigBlockMopar

Re: throttle response - which carb has the best? - 12/23/12 03:01 PM

Quote:

I've used the old carters on previous mopars, and quite frankly I never liked the lack or response or that 1-2 sec delay when you put down the gas.




1-2 seconds? Sounds more like the operator needs a tune-up first.
Posted By: Cab_Burge

Re: throttle response - which carb has the best? - 12/23/12 11:50 PM

Quote:

Quote:

I've used the old carters on previous mopars, and quite frankly I never liked the lack or response or that 1-2 sec delay when you put down the gas.




1-2 seconds? Sounds more like the operator needs a tune-up first.

The accelerator pump adjustment arm and squirter size should be check now
Posted By: Cuda367

Re: throttle response - which carb has the best? - 12/24/12 12:32 AM

I wish I could give you a personnel experience, but I can't. I am very interested in the new Street Demon carb. If it works as it should, I beleive it has all the street demands for a less than 400 inch motor meet in spades. When right the old thermo quad was almost unbeatable, and they took that tech and tried to solve the short comings. I just wish they offered it bigger. At 750 or so it could be unreal as a street strip carb.
Posted By: dangina

Re: throttle response - which carb has the best? - 12/24/12 12:57 AM

Quote:

Quote:

Quote:

I've used the old carters on previous mopars, and quite frankly I never liked the lack or response or that 1-2 sec delay when you put down the gas.




1-2 seconds? Sounds more like the operator needs a tune-up first.

The accelerator pump adjustment arm and squirter size should be check now



the operator does need a tune up first! The carter and thermoquads i use to have weren't bad carb's - They weren't that responsive off the line - I'd even take it to a tuner and I'd still get a delay of 1/2 second or so when you stop on the gas before the engine kicked in. Although I do admit the old motors were pretty close to stock, I'm looking at a better response time, as instant as possible. I'm still going to take it to a tuner when the engine is in
Posted By: MR_P_BODY

Re: throttle response - which carb has the best? - 12/24/12 01:06 AM

Quote:

Quote:

Quote:

Quote:

I've used the old carters on previous mopars, and quite frankly I never liked the lack or response or that 1-2 sec delay when you put down the gas.




1-2 seconds? Sounds more like the operator needs a tune-up first.

The accelerator pump adjustment arm and squirter size should be check now



the operator does need a tune up first! The carter and thermoquads i use to have weren't bad carb's - They weren't that responsive off the line - I'd even take it to a tuner and I'd still get a delay of 1/2 second or so when you stop on the gas before the engine kicked in. Although I do admit the old motors were pretty close to stock, I'm looking at a better response time, as instant as possible. I'm still going to take it to a tuner when the engine is in



The smaller the carb is, the more responsive it will
be but it also hurts HP so you have to come up with
a balance... with a 1050 on my 405ci I dont have a
problem because I dont foot brake.. so I am up in
the revs soon enough using the trans brake... I have
a 850 Holley on my 416 street car and it reacts quickly
Posted By: quickd100

Re: throttle response - which carb has the best? - 12/24/12 01:37 AM

My old 750 Carter AFB had explosive throttle response. My 2 850 thermoquads on the tunnelram are just as good if not better.Dave
Posted By: MR_P_BODY

Re: throttle response - which carb has the best? - 12/24/12 02:00 AM

Quote:

My old 750 Carter AFB had explosive throttle response. My 2 850 thermoquads on the tunnelram are just as good if not better.Dave



And if you put 2 2bbls on that tunnel ram it would
be MUCH faster responding... its just a matter of
how much air you move through the venturi per RPM
Posted By: Twostick

Re: throttle response - which carb has the best? - 12/24/12 04:12 AM

If there is any discernible lag in response to pedal input, and your tuner is OK with it, you need a new tuner. Unless of course you have major flaws in your combo that the tuner has pointed out and you haven't addressed ie too much cam and not enough converter or gear.

Kevin
Posted By: Kevins493

Re: throttle response - which carb has the best? - 12/24/12 05:35 AM

Quote:

Quote:

Quote:

Quote:

I've used the old carters on previous mopars, and quite frankly I never liked the lack or response or that 1-2 sec delay when you put down the gas.




1-2 seconds? Sounds more like the operator needs a tune-up first.

The accelerator pump adjustment arm and squirter size should be check now



the operator does need a tune up first! The carter and thermoquads i use to have weren't bad carb's - They weren't that responsive off the line - I'd even take it to a tuner and I'd still get a delay of 1/2 second or so when you stop on the gas before the engine kicked in. Although I do admit the old motors were pretty close to stock, I'm looking at a better response time, as instant as possible. I'm still going to take it to a tuner when the engine is in


If they're set up right they work just fine. Been 1.34 60' with 2 eddy 750 performer (AFB style) carbs. Car will 60' as good or better than most dominator/backhalf/4 link type cars that run the same et.
Posted By: gregsdart

Re: throttle response - which carb has the best? - 12/24/12 12:34 PM

Throttle response on a constant flow FI setup is so great because with no accelerator pumps the idle has to be so rich that alky actually puddles on the intake valves. It doesn't get much better than that. The reason I mention it is a fat idle in a carb will help a bit also. Of course with gas you have a narrower tuning/HP window, so finding the perfect combo of idle/accelerator pump/carb size can be pretty tricky. But I can see why D100s Hemi responds so well. Two small venturis to maintain decent AFR as it transitions from off idle to full jet flow to secondary opening. Not to mention his tuning skills.
Posted By: dangina

Re: throttle response - which carb has the best? - 12/24/12 01:40 PM

thanks for the great info guys! Maybe I should just stop playing around with rebuilds and start off new...I read that the smaller ones will get you better response but sacrifices hp, but I've also read the 383's respond better with bigger carbs when you swap out the cams and intake. Its an 71 rr air grabber car I don't know if that helps i the decision making...

Quote:

Between the two you have, I would go with the Holley. I bracked raced for years using a 750 D.P. I finally wore it out. I am currently using a QuickFuel 680 vacuum secondary, and am very well pleased with it on my 360. I would recommend it for your use. The electronic choke would probably come in very handy on those cool Canadian days.



I thought about getting a carb with an electric choke for our cooler springs/falls. I never have owned one and was curious how do they work? Do you just have it on a switch and turn it off when your car is warmed up?
Posted By: emarine01

Re: throttle response - which carb has the best? - 12/24/12 02:49 PM

Annular boosters w/any double pump
Posted By: tvt59

Re: throttle response - which carb has the best? - 12/24/12 03:00 PM

On my bracket cars I always used 1 to 1 linkage on them. After sorting them out They revved like a fuel injected car. They worked good on the street also. Just could not get any fuel mileage with them.
Posted By: fourgearsavoy

Re: throttle response - which carb has the best? - 12/24/12 04:39 PM

Some good features on this carb and it might be big enough for your application
http://www.demoncarbs.com/1900.asp

Gus

Attached picture 7516672-savoyburnout.jpg
Posted By: Cab_Burge

Re: throttle response - which carb has the best? - 12/24/12 06:36 PM

My 383 dart has a Holley 1850 that I added a electric choke on it, I hooked the positive feed wire to the ignition circuit that feeds the coil resitor that way it is on as soon as I start the car, it work great after I got it adjusted properly
As far as your hesitation your experiencing, all cars should have no discernable hesitation in nuetral or in gear If you do there is a problem, not neccessarily you But the carbs. do All things mechanical can go bad and be faulty, but they can be fixed also I've seen carbs. act up with old gas in them, some wouldn't even start without priming them with fresh gas or starting fluids
Posted By: Dodgem

Re: throttle response - which carb has the best? - 12/24/12 06:45 PM

383 4 speed hands down the 750 DP and it will be great on the 451 stroker too!!!!



Posted By: dangina

Re: throttle response - which carb has the best? - 12/24/12 10:15 PM

Quote:

Annular boosters w/any double pump



I haven't heard of these, thanks for the tip! read some interesting articles on this, do you prefer these over the downlegs?
although I also read that they are not recommemded for the Perf, Perf/RPM, or RPM Airgap, I wonder why? to bad because I'm running the perf/rpm intake...

so many choices now - I hope I have some extra cash over christmas!
Posted By: SpareParts

Re: throttle response - which carb has the best? - 12/24/12 10:22 PM

Quote:

Quote:

Annular boosters w/any double pump



I haven't heard of these, thanks for the tip! read some interesting articles on this, do you prefer these over the downlegs?

so many choices now - I hope I have some extra cash over christmas!



Annular carbs set the booster further down in the venturi to deliver the vacuum signal quicker, the boosters are typically larger than a down leg but more responsive. However due to their size they can become a restriction at high rpm.
Posted By: cudaman1969

Re: throttle response - which carb has the best? - 12/24/12 11:11 PM

If your idle fuel mix is correct(air and fuel bleeds) any carb will be responsive. It has to be rich enough, at idle, so there is a good transition when the main circuit opens.A 10 or12 to 1 ratio is what I start with and if right no acc. pump is needed. Read one of the old Holly carb books. Every carb has to be reworked to each engine combo, vacume signal, to really dial it in so it's responsive.
Posted By: Cab_Burge

Re: throttle response - which carb has the best? - 12/26/12 01:34 AM

Quote:

If your idle fuel mix is correct(air and fuel bleeds) any carb will be responsive. It has to be rich enough, at idle, so there is a good transition when the main circuit opens.A 10 or12 to 1 ratio is what I start with and if right no acc. pump is needed. Read one of the old Holly carb books. Every carb has to be reworked to each engine combo, vacume signal, to really dial it in so it's responsive.

I've found just the opposite to be better on my cars and carbs, 14.8 or leaner at idle and part throotle cruise and 12.8 to 13.5 at WOT, depending on fuel being used and altitude being driven at. A lot of the Holley carbs, especially the race ones like the D.P. and Dominators, are real rich at idle and part throttle like he stated, that can and will foul the colder hear range spark plugs and possibly wash the cylinder walls down and dry them out OP, you might want to invest in a wide ban O2 kit, they can be a real help on tuning the carbs or EFI, especially when you get real close to perfect
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