So what is the deal with Edelbrock carbs
Team Owner
Joined: Oct 2004
Posts: 81,242
Likes: 3,061
From: altered state
St. Jude Donor '05
Same cornering (cutting out) problems with an Edelbrock (since it was new, too) on a car I had years ago...Irritating to say the least.
It eventually went in the trash.
The seem to be calibrated for a stock replacement scenario, the off idle hesitation is common-If you want to keep it youllhave to play with it.
Personally I prefer the new Holley carbs they have come a long way.
It eventually went in the trash.
The seem to be calibrated for a stock replacement scenario, the off idle hesitation is common-If you want to keep it youllhave to play with it.
Personally I prefer the new Holley carbs they have come a long way.
Burning Brakes
Joined: Jul 2000
Posts: 963
Likes: 0
From: melbourne,Australia
My experience with edel 750 is now over;however there were two problems with it;#very sensitive to fuel pressure...any more than 6 psi led to flooding.....#2 the accelerator pump seal wasn't sealing properly and i got a pronounced off idle burp/stumble that i couldn't manage out no matter what combination of rods/valves adjustments i used....other that that ran well on a strong 383...the holley 750 vac sec was easier to set up....john
Thread Starter
Team Owner
Joined: Apr 2002
Posts: 62,198
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From: All humans are vermin in the eyes of Guru VA
Cruise-In IV Veteran
Cruise-In V Veteran
I used an Edl 750 carb on a single plane for 10 years.
during that 100,000 miles I went around a few turns without a carb problem.
If you can run out a float bowl .......... your fuel pressure is low
I had the Edl carb when I ran some Nevada open road races. The Silver state classic is 92 miles long and I averaged right below my class limited average of 150 mph. with slow 50-60 mph turns and 174 mph on the straights
during that 100,000 miles I went around a few turns without a carb problem.
If you can run out a float bowl .......... your fuel pressure is low
I had the Edl carb when I ran some Nevada open road races. The Silver state classic is 92 miles long and I averaged right below my class limited average of 150 mph. with slow 50-60 mph turns and 174 mph on the straights
Le Mans Master
Joined: Jan 2000
Posts: 8,719
Likes: 106
From: Canada
I've been running the Edel 750 mech dp on my 383 stroker for @ 5 yrs now it replaced a Holley 750 mech. dp that leaked. Seat of pants feel was that right out of the box I was giving up hp at the top end (over 5700 rpm) but that carb has run beautifully for these yrs and no worries of leaking. For @ $200 for a refurbished unit I sure have no complaints.
Burning Brakes
Joined: Jul 2006
Posts: 1,047
Likes: 12
From: SoCal
I've been running an Edelbrock dual-quad setup (2 X 500CFM) for a couple of years now. No hesitation off idle, but I did experience one episode of engine stall after a sharp left turn - that was when I was "shaking down" the car after its rebuild, and I would imagine that the fuel regulator was set too low (I don't know for sure what the fuel pressure was set to - too long ago to remember).
Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
I have been trying to get a feel for edelbrock carbs.
Seems the common complaints are:
1.) bowl capacity
2.) Flooding while cornering (float height according to edelbrock)
Other than that they seem to be a darn good carb for easy tuning, and every day reliability. They are junk, get over it that is two pretty big complaints! That is like saying your tires are great exept they are bald and flat!
So I am building a 396 small block. I am thinking about a decent hyd roller.(its a roller block) For a stroked out CI like that you need a 750 CFM carb at least, don't let the conservatives try to under cut your needs or your just wasting that engine, myself I would run an 850 double pumper, I like to use all my horsepower, but thats just me.
Seems the common complaints are:
1.) bowl capacity
2.) Flooding while cornering (float height according to edelbrock)
Other than that they seem to be a darn good carb for easy tuning, and every day reliability. They are junk, get over it that is two pretty big complaints! That is like saying your tires are great exept they are bald and flat!
So I am building a 396 small block. I am thinking about a decent hyd roller.(its a roller block) For a stroked out CI like that you need a 750 CFM carb at least, don't let the conservatives try to under cut your needs or your just wasting that engine, myself I would run an 850 double pumper, I like to use all my horsepower, but thats just me.
Joe Sherman WON the Engine Masters with an 800 Eddy. It ca't be as bad as everyone says it is.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
The Edelbrock carb (Carter AFB re-make) is a simple, inexpensive, readily-available carburetor that serves a purpose on mildly used street machines. For normal driving, they are relatively trouble-free.
As a performance carb, they suck, IMO. If you are drag racing, the Holley is your best choice, as it can be tweaked quickly for optimum power output under different track/weather conditions. But, as an "all-around" carb that can perform well, make smooth transitions from idle/off-idle/cruise/WOT, and be economical, too...the Q-Jet is the champ.
As a performance carb, they suck, IMO. If you are drag racing, the Holley is your best choice, as it can be tweaked quickly for optimum power output under different track/weather conditions. But, as an "all-around" carb that can perform well, make smooth transitions from idle/off-idle/cruise/WOT, and be economical, too...the Q-Jet is the champ.
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Le Mans Master
Joined: Oct 2010
Posts: 6,887
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From: melbourne florida
2023 C3 of the Year Finalist - Modified
in almost every case when someone said it only needs a 650 the car ran better with a bigger carb. ratings between companies are not standardized and are a "suggested serving " like a t.v dinner
Le Mans Master
Joined: Dec 2006
Posts: 5,557
Likes: 9
From: Oquirrh Mountains
St. Jude Donor '09
The cornering/stumbling issue with afb style carbs is due to a "trough" cast into the main body of the carburetor. It can be seen in the picture below above and to the right of jet "B" at the back of the carb.
High lateral g's allow fuel to transfer from one side of the carburetor to the other. This results in flooding on one side ans a lean condition on the other - not good. The trough is there to equalize air pressure from side to side; but it is redundant due to the bowl vents. A generous dab of epoxy right in the middle of this trough will solve your problem.
High lateral g's allow fuel to transfer from one side of the carburetor to the other. This results in flooding on one side ans a lean condition on the other - not good. The trough is there to equalize air pressure from side to side; but it is redundant due to the bowl vents. A generous dab of epoxy right in the middle of this trough will solve your problem.
Last edited by Ben Lurkin; Oct 21, 2012 at 03:03 PM.
8th Gear
Joined: Feb 2018
Posts: 8
Likes: 0
the edelbrock carbs are a good carb (under 650 cfm) for a mild performance engine unless you like to go around corners hard, the design of the fuel bowl and the jet placement cause the fuel to wash away from the jets on one side of the carburetor if you corner hard in one direction and if you turn the other way the jets on the other side will have the same problem.
the off-idle/transistion system is not designed to supply enough fuel for most engines on the 750 & 800 cfm carbs of this design, that is why so many of the owners of these carbs will complain of a lean off idle hesitation problem at part throttle. The fuel bowl volume/size is the same with all the afb/performer and avs/thunder carbs from 500 to 800 cfm. The only real change they do to the off road carbs is a spring loaded needle and seat so i see no advantage to that for a application such as a Corvette.
the 600 and 650 cfm carbs from Edelbrock are good carbs and easy to adjust but they do have thier limitations so if you are after maximum power think about a Holley, Quick Fuel or Demon carb (or a Q-jet).
the Edelbrock carbs are made by Weber (Magneti Marelli) who bought the patents from Carter so they are the same basic carb but the calibrations are slightly different.
henry @ olescarb
the off-idle/transistion system is not designed to supply enough fuel for most engines on the 750 & 800 cfm carbs of this design, that is why so many of the owners of these carbs will complain of a lean off idle hesitation problem at part throttle. The fuel bowl volume/size is the same with all the afb/performer and avs/thunder carbs from 500 to 800 cfm. The only real change they do to the off road carbs is a spring loaded needle and seat so i see no advantage to that for a application such as a Corvette.
the 600 and 650 cfm carbs from Edelbrock are good carbs and easy to adjust but they do have thier limitations so if you are after maximum power think about a Holley, Quick Fuel or Demon carb (or a Q-jet).
the Edelbrock carbs are made by Weber (Magneti Marelli) who bought the patents from Carter so they are the same basic carb but the calibrations are slightly different.
henry @ olescarb
8th Gear
Joined: Feb 2018
Posts: 8
Likes: 0
I used an Edl 750 carb on a single plane for 10 years.
during that 100,000 miles I went around a few turns without a carb problem.
If you can run out a float bowl .......... your fuel pressure is low
I had the Edl carb when I ran some Nevada open road races. The Silver state classic is 92 miles long and I averaged right below my class limited average of 150 mph. with slow 50-60 mph turns and 174 mph on the straights
during that 100,000 miles I went around a few turns without a carb problem.
If you can run out a float bowl .......... your fuel pressure is low
I had the Edl carb when I ran some Nevada open road races. The Silver state classic is 92 miles long and I averaged right below my class limited average of 150 mph. with slow 50-60 mph turns and 174 mph on the straights
Another point to make is, everyone thinks getting the bigger carb means more power. You need to match the carb to the demands of your engine. Most engines aren;t going to move as much air as you think. Figure out how much air at most your engine can move, this has to do with your MAX RPM and displacement, also your valves, head and intake flow and even your exhaust. Do the numbers and I think most people would be surprised.
8th Gear
Joined: Feb 2018
Posts: 8
Likes: 0
Let me sum it up.Make a sharp fast u turn and the Eldelbrock carb will out of 10 times stall the engine if you don't play with the gas pedal.Almost all Edelbrock carbs have some sort of hesitation just off idle or on very hard accel.The carb has limited amounts of tune-ability,such as only 3 adjustments for the accelerator pump.The good stuff about them they holes a tune very well and have a great idle.They also can adjusted for fantastic mpg.Easy to install.
Racer
Joined: Oct 2009
Posts: 280
Likes: 1
From: cleveland Ohio
so,,,is ben lurkin right.i have off idle hesitation,,hate it,,tried different things etc etc a dab of epoxy,,which should be removable if wanted,,in trough. what do you think mr. lars tom in cleveland,oh.
Instructor
Joined: Jun 2015
Posts: 193
Likes: 34
From: Ohio
The new AVS 650 that I purchased was returned after I could not for the life of me get rid of a mid range lean condition. No matter what combination of metering rods, jets, and springs I used I could not get rid of the lean condition. Put on a summit 600 out of the box with no adjustment at all and it ran great.