CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
Welcome to ThirdGen.org!
Welcome to ThirdGen.org.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!
Are there any carbs that are more tunable and perform better than a Edelbrock Performer series carb? Should I sell my performer and by the AVS version? What do you guys think?
Sorry, I don't want to start a flame war. I just want to have an intelligent conversion over the advantages/disadvantages of different brands and what can be tuned over others.
The carb is not the problem. The problem is the tuners inability to accuratly determine whether they are too rich or too lean in any particular driving mode. Until you know where you are now, you're only guessing which way to go.
Richer or leaner.
A air fuel ratio meter helps a lot. So does a good selection of tuning parts like jets and rods and accelerator pump shooters and the instruction book that comes with your Edelbrock.
Tuning a Holley or a Qjet is basicely the same routine just slightly different methods. I find my Edelbrock very easy to work on.
Many many many times a "carb problem" is actually a ignition problem.
A mechanical secondary Holley Double pumper will almost always pick up ET and MPH on an Edelbrock performer carb in my experience if you are just talking about drag racing.
On my old 350HO, we tried every combination of jetting, springs and needles on my performer 600 carb. Swapped to a 650 cfm Speed Demon and picked up a lot of ET and MPH. I honestly think the performer was just too small for my motor.
I have a 305 rigtht now but plan on putting in a 350, but this may not happen for another 12 months or so. I know the 750 was a bad choice for this engine so what I did was called Edelbrock and they recommended a jet and rod change to make it run better on this engine. I'm really thinking about selling this Edelbrock and buying a 650CFM Demon Carb speed Demon model.
I've never been a fan of the Carter AFB or AVS carbs. They're OK, not "bad" or anything like that; but a Holley will make more power, every time. The Carter design is maybe a bit more street-friendly; lower maintenance, potentially a little better on gas (but not much), and so on.
The Carter design is pretty easy to work on though, and has enough "handles" for tuning on it, to where you can usually get them to work on almost anything. If you have one that won't tune, it's probably broken somehow, and you'd get better results if you repaired it.
But if you replace it with a Demon, the car will almost certainly go faster.
__________________ Numquam ponenda est pluralitas sine necessitate. — William of Ockham, from Quaestiones et decisiones in quattuor libros Sententiarum Petri Lombardi
Roughly paraphrased into modern English, and applied to figuring out what's wrong with your car:
The simplest explanation that fits all the facts is probably the right one.
Originally posted by MKnight I have a 305 rigtht now but plan on putting in a 350, but this may not happen for another 12 months or so. I know the 750 was a bad choice for this engine so what I did was called Edelbrock and they recommended a jet and rod change to make it run better on this engine. I'm really thinking about selling this Edelbrock and buying a 650CFM Demon Carb speed Demon model.
I think a 650 Speed Demon would honestly be too much carb for your 305, should be perfect on your 350.
Between any of these carbs, once they are properly tuned, there isn't much more than a tenth or two in the quarter.
So why waste money jumping from one carb to another? If anything you should trade that 750 cfm in for the Edelbrock 600 cfm (1406), which is better for a 305--or a 350 for that matter.
I have an Edelbrock 1806, i think that is the 650Cfm with the vacuum secondaries. This carb came with the car and i was told it has about 3000 miles on it but it was sitting for a few years. My question is how is everyone else tuning theirs, i dont have a A/F ratio guage but i know mine is running rich from reading the plugs. I hooked up a vacuum guage to my carb and turned the A/F screws till i got the most vacuum. I was told that this is a proper way to do it if you dont have a nice expensive guage. does anyone think i am running the wrong jets or faulty jets?
Also, am i running the right carb for my car? I have 3.73 Gears in the back with a T5 tranny. I was told the vacuum secondaries is killing my acceleration, is this true? If i get a double pumper will my times increase? I have a 350 with crappy heads (882) and no special cam. Those are 2 other things that i want to do to get it a little peppier.
I had two carbs that I ran back to back at the track. Holley 600 DP, Edelbrock 750. I had done some jetting/rod staging adjustments on the Edelbrock, Holley was box stock. I ran a 14.4 with the Edelbrock and a 14.6 with the Holley DP. Your Edelbrock is probably not "slowing you down" at all if it is tuned properly.
If you are serious about performance fill out the info sheet at www.pro-systems.com and let Patrick built you a carb specific for you combo. He will use the computer to develop a true race fuel curve (not a corporate design), and a custom multi-adjustable bleed configuration that allows this model almost infinite adjustability.
Dont get caught up in the CMF rating of a carb, its what sell magazines.
It is interesting that some of the "smaller" carb companies do not even give their carburetors a cfm or flow rating. Many are "rated" by engine size. They just prefer you call them and get a proper recommendation. It is obvious as to why it seems a recommendation from a tech or carb builder would be prefered over just selecting one based on its cfm "rating". There seems to be a lot of such misinformation that comes with cfm ratings which each model carries.
Recently I called Patrick for a recommendation and he said you need "x" carburetor. I was thinking to myself well what is that and so I asked what it was. He explained to me how these things are built and why flow ratings are sort of indifferent so they do not give theirs a "cfm" number. What is most important is the flow in terms of your application so a recommendation from a good technician is your best bet.
We can argue this into the ground, I just want to point out how many of the big name race companies use Holley and Demon carbs instead of Edelbrock. If you went from a 600 cfm Holley to a 750 cfm Edelbrock, I would expect you to pick up some ET and mph. If you went from the 750 Edelbrock to a 750 Holley DP, I would expect you to again pick up some ET and MPH. Go CFM for CFM here.
yeah i have heard for race holleys are better but for street edelbrocks are better i have both andi love my edelbrock for the road very easy to tune. another thing is that 750 is too big for a 305 your dumping way to much fuel. yeah you can jet it down but only so far. i have a worked 350 and i'm use a speed demon 750 and thats what the machine shop guys said to use so hats what i'm doing.
__________________ 87 Z28 with a T-5 rear 4.10 TPI R.I.P.
87 camaro 3.42 car for sale as roller
I must add this, the flow #'s of Demons surpass anything out there. Thats why BG tech support will normally recomend a smaller cfm carb than the other brands. And lets not forget about the different styles of boosters available. My 575 Speed Demon (mech secondaries) has annular boosters in both the primaries and secondaries and can flow way more fuel than my 350 will ever need. Its so tunable with the idle eze baseplate and four corner idle/mixture screws that its become a pleasure to mess with it in test & tune days. Not for the ham fisted though a 1/8th turn at any corner will make a big difference.
cfm is no problem ive seen some 850's on a 305 just jetted all the way down.. really a carb is a carb it will perform as well as the person tuning it.. every carb has its flaws but get one brand you like learn everything you can about it to fix whatever little glitches it has and stick with it, the biggest probelm ive had with carbs is thinking they are going to work like the other brand... swtiching from edelbrock to holley... ect.. right now im running a 770 on mine takes a while to get it just right... alot to consider spring size if your running vacume secondaries.. jet size for the setup you have... best tool is an a/f ratio gauge if you can keep it in the green through most of your rpm range you know your doing something right...
I'm a big fan of the Quick Fuel Carburators (plus I can get people good deals on them). I have a 750 myself. Several guys I know also have them and really rave about how much more they like them versus other brands they have used.