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Re: Why don't more people run Edelbrock carbs? [Re: 451Mopar] #1940866
10/29/15 07:38 AM
10/29/15 07:38 AM
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Oakdale CT
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Originally Posted By 451Mopar
Originally Posted By gdonovan
If you put the time in to learn how they work and how to modify them they run just as well as a Holley of comparable size.


I think that I spent more money on tuning parts for my carbs than what the carbs cost. I must have over $1,000 in jets, rods, power valves, screw in restrictions, air bleeds, step-up springs, discharge nozzles, vacuum secondary springs, accelerator pumps and pump cams, pin drills, and other specialized carb tools.


I have 2-3 Carter strip kits (because I'm running 3 AFBs currently) and a pin drill set, pretty much all you need to make them go. A touch of epoxy here, an adjustment there and you are off and running.

Oh- The secondaries are adjustable on the AFB, you just need to know how to do it and there is more than one way.

If I have a complaint about the AFB series of carbs it is the fact the newer fuels do boil out quicker when the car is parked due to the aluminum construction. Since I run electric fuel pumps (for one reason or another) its really a non-issue for me.

When I take the 5.9 magnum Duster back out in the spring I'm going to give a Holley (780 vacuum sec) I have here a shot to see if the car turns different numbers. When things are less hectic in a few weeks I'll make a posting inquiring about how the carb should be setup for the application.

Since it is comparable in size (Current carb is an older Carter 750 cfm AFB) it should be an apples to apples comparison aside from the fact one has mechanical secondaries and the other has vacuum.




"I think its got a hemi"
Re: Why don't more people run Edelbrock carbs? [Re: Hot 340] #1940872
10/29/15 08:28 AM
10/29/15 08:28 AM
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Even though I use Edelbrocks ultimately the lack of pump shot and secondary opening does seem to slow 60 ft some what. But when $ are compared I didn't find it cost effective for my program to pony up $1600 or so for a pair of modified Holley's to gain approximately .05 in ET.
Doug

Re: Why don't more people run Edelbrock carbs? [Re: dvw] #1940887
10/29/15 09:42 AM
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Originally Posted By dvw
Even though I use Edelbrocks ultimately the lack of pump shot and secondary opening does seem to slow 60 ft some what. But when $ are compared I didn't find it cost effective for my program to pony up $1600 or so for a pair of modified Holley's to gain approximately .05 in ET.
Doug
if your running 750's then there's probably a way to open up the accelerator pump well for the larger volume 800 pump.

Re: Why don't more people run Edelbrock carbs? [Re: Hot 340] #1940894
10/29/15 09:56 AM
10/29/15 09:56 AM
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if one will study the tuning booklet supplied with the edelbrock carbs they will notice that a "step" in metering is 4%. what i have done is use the percentage of change to dictate a step and not orifice sizes. i put together a cheat sheet that gives the square inches of area for all jet and metering rod sizes/steps. i figure everything on percentage of change using both jet area and rod step area. never do i grab a jet or rod out of the box and just figure i'm changing "one step".

as far as the pump nozzles go you can make them anything you want with small pin drills.

to my knowledge there were two types of floats made for afb's, small and large. none of the edelbrocks have the large but some OEM carbs did, like a 440 avs. i don't think the smaller float gives as good of fuel control as the larger. i have found that for what i do the smaller needle and seats seem to perform and drive better and i think that's due to poorer control with the smaller float.

Re: Why don't more people run Edelbrock carbs? [Re: dvw] #1940895
10/29/15 10:01 AM
10/29/15 10:01 AM
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Oakdale CT
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Originally Posted By dvw
Even though I use Edelbrocks ultimately the lack of pump shot and secondary opening does seem to slow 60 ft some what.


The AFB on my Duster is exceptionally crisp, its all in the tune.

There is no bogging; you stab it and the car stands up and goes.

Didn't even touch the shooters.

I'll give you a clue though- The number one problem I have noted on some models of the AFB is they mix far to much air with the fuel in the booster emulsion circuit. Restricting the amount of air that is mixed with the fuel in that circuit speeds up how quickly fuel is being pulled out of the booster.

No need for a larger pump shot if the fuel is being drawn out of the booster darn near instantly. You will have to re-jet of course if you are going to take this route as it does change the calibration.


track_1.jpg
Last edited by gdonovan; 10/29/15 10:04 AM. Reason: TO make point more clear



"I think its got a hemi"
Re: Why don't more people run Edelbrock carbs? [Re: Hot 340] #1940914
10/29/15 10:48 AM
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the upper holes in the emulsion tube can be soldered up. there's also a hole high up where the tube enters the cluster that i believe is the "economizer" that can be plugged and is absent in some carbs. i think too much is made of having a lot of pump shot. it's part of the bracket racer mentality to go for big pump shots, whether it's needed or not. to me it shows the lack of ability to tune a carb.

Re: Why don't more people run Edelbrock carbs? [Re: lewtot184] #1940947
10/29/15 11:59 AM
10/29/15 11:59 AM
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Originally Posted By lewtot184
it's part of the bracket racer mentality to go for big pump shots, whether it's needed or not. to me it shows the lack of ability to tune a carb.


Been using narrow band O2 for tuning since the late 80's, the gauge tells you all you need to know. Just work on it circuit by circuit and they run like a top in no time flat.

I think in the early 90's I was given one of the new aluminum Holleys to play with. A LOT of time was spent trying to get it right, it was incredible how crude the fuel circuits were and rough the transitions were from circuit to circuit. Had to drill the shooters and adapt a 50 cc pump to get rid of a lean spot on the primary side. The thing would go from full rich to full lean on the gauge in a heartbeat, there was almost no in between. I think the Holley strategy was to just have it "run rich" all the time to cover the transitions, stands out like a sore thumb if you have the tools though.

Still have it hanging from the garage wall.

I'm willing to give the 780 I have a shot as it is only a couple years old and perhaps Holley has made some strides since the 90's on calibrations and circuits.




"I think its got a hemi"
Re: Why don't more people run Edelbrock carbs? [Re: gdonovan] #1940960
10/29/15 12:23 PM
10/29/15 12:23 PM
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So, what PSI do you other Edelbrock folks use for your fuel supply? I've heard that they are very sensitive to fuel pressure greater than 5.5 PSI.

Re: Why don't more people run Edelbrock carbs? [Re: preddy] #1941000
10/29/15 01:32 PM
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Originally Posted By preddy
So, what PSI do you other Edelbrock folks use for your fuel supply? I've heard that they are very sensitive to fuel pressure greater than 5.5 PSI.


I can't comment on the Edelbrocks as I have a fine collection of Carter AFBs I tinker with but I don't even bother running a regulator. The Duster just runs an electric self-regulated pump and the GTX runs an electric feeding a Carter race mechanical. When I was running the 6-pack hood with a fuel gauge I'd see as high as 12 psi which never seems to bother it.




"I think its got a hemi"
Re: Why don't more people run Edelbrock carbs? [Re: preddy] #1941004
10/29/15 01:39 PM
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I run 6 psi.
Doug

Re: Why don't more people run Edelbrock carbs? [Re: Monte_Smith] #1941177
10/29/15 06:52 PM
10/29/15 06:52 PM
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Originally Posted By Monte_Smith
Originally Posted By dannysbee
There are lots of nhra stockers running in the 10' s with one AVS. Just a AFB, edelbrock with a adjustable air door.
Probably ONLY because they HAVE to



Right...

Brand X strikes again...

Re: Why don't more people run Edelbrock carbs? [Re: Hot 340] #1941281
10/29/15 09:24 PM
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I've tuned cars w/ both Holleys and Carters and don't really have a preference. They each have their own pros and cons.

I've ridden in cars w/ each...some run well, some not. It undoubtedly comes down more to the person doing the tuning than the carb itself.

Re: Why don't more people run Edelbrock carbs? [Re: Cogito] #1941319
10/29/15 10:29 PM
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Originally Posted By Cogito
I've tuned cars w/ both Holleys and Carters and don't really have a preference. They each have their own pros and cons.

I've ridden in cars w/ each...some run well, some not. It undoubtedly comes down more to the person doing the tuning than the carb itself.
i agree.

Re: Why don't more people run Edelbrock carbs? [Re: preddy] #1941321
10/29/15 10:33 PM
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Originally Posted By preddy
So, what PSI do you other Edelbrock folks use for your fuel supply? I've heard that they are very sensitive to fuel pressure greater than 5.5 PSI.
i think the psi issue has more to do with the small floats lack of control. the 5-6 psi thing keeps the fuel control happy with the availiable parts. i have run and do run a little higher without issue but i juggle parts.

Re: Why don't more people run Edelbrock carbs? [Re: gdonovan] #1941502
10/30/15 03:05 AM
10/30/15 03:05 AM
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Originally Posted By gdonovan
Originally Posted By Monte_Smith
Originally Posted By dannysbee
There are lots of nhra stockers running in the 10' s with one AVS. Just a AFB, edelbrock with a adjustable air door.
Probably ONLY because they HAVE to


If you put the time in to learn how they work and how to modify them they run just as well as a Holley of comparable size.

I knew all of the above statements would be made. grin

Re: Why don't more people run Edelbrock carbs? [Re: RSNOMO] #1941579
10/30/15 11:11 AM
10/30/15 11:11 AM
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Originally Posted By RS23U1G
Originally Posted By dvw
Originally Posted By Mr.Yuck
because they suck... ok to be fair they work well on a street car, meaning not raced. If you want to go racing with them you'll need two. Not hard to tune, they just don't tune well. If you run a mild BB you'll need the 800 thunder.

I've won a fair amount of races in both Pro and N/SS with them.
Doug



You ain't alone...

For carbs 'that suck', there sure are a lot of 'em out there kicking serious a$$...


apples to onions. you are running TWO and most NSS guys would LOVE to run a pair of Holleys if they could. In a SINGLE carb configuration a Holley is far better.

Re: Why don't more people run Edelbrock carbs? [Re: Mr.Yuck] #1941596
10/30/15 11:41 AM
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I have one on my 427" SBF Stroker in my Cobra replica and after some minor tuning of the rods and springs it works better ON THIS CAR than any holley.

I have a fair amount of experience tuning the old 68-71 440 AVS's and the cobra really needed a tractable roll-on to the secondaries, the double pumper worked awesome but when you roll on the power in a curve just slightly too hard on street tires a Cobra can try to swap ends on you. The Thunder AVS works just right for this combo, the only other thing the Edelbrock needed was to convert it to a dual line feed because without it you rely on the flow passing through the body to keep both sides/bowls filled. AT WOT in a light car the single feed wasn't keeping up and would go lean under hard acceleration. The dual line feed did the trick.

On the track I can run race tires and use a DP more effectively, but honestly I've got the AVS so well-tuned now I don't really worry about it.


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: Why don't more people run Edelbrock carbs? [Re: lewtot184] #1941603
10/30/15 12:04 PM
10/30/15 12:04 PM
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Originally Posted By lewtot184
Originally Posted By preddy
So, what PSI do you other Edelbrock folks use for your fuel supply? I've heard that they are very sensitive to fuel pressure greater than 5.5 PSI.
i think the psi issue has more to do with the small floats lack of control. the 5-6 psi thing keeps the fuel control happy with the availiable parts. i have run and do run a little higher without issue but i juggle parts.
Think they recommend 5.

2004-11-27 04.20.39.jpg

Fastest 300
Re: Why don't more people run Edelbrock carbs? [Re: Hot 340] #1941623
10/30/15 12:36 PM
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pretty sure the recommendation is no more than 6psi. i've fudged on that a little without issue. i firmy believe the floats are the control issue.

Re: Why don't more people run Edelbrock carbs? [Re: Mr.Yuck] #1941624
10/30/15 12:39 PM
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Originally Posted By Mr.Yuck
Originally Posted By RS23U1G
Originally Posted By dvw
Originally Posted By Mr.Yuck
because they suck... ok to be fair they work well on a street car, meaning not raced. If you want to go racing with them you'll need two. Not hard to tune, they just don't tune well. If you run a mild BB you'll need the 800 thunder.

I've won a fair amount of races in both Pro and N/SS with them.
Doug



You ain't alone...

For carbs 'that suck', there sure are a lot of 'em out there kicking serious a$$...


apples to onions. you are running TWO and most NSS guys would LOVE to run a pair of Holleys if they could. In a SINGLE carb configuration a Holley is far better.


Well in the NMCA NSS class if you are running in the AFX 9.75 or quicker classes you are allowed to run the Holley or QuickFuel carbs. Some do and some do not as there is really not a huge difference if any. Some may gain .10 or .05 and some I do know stayed the same. So why all the added expense with a not so much improvement shruggy

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