Jet Carbs? Quadrajets
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Jet Carbs? Quadrajets
Does anybody have any experience with a rebuilt QJ from Jet?
I cant understand how they can possibly sell a one size fits all carb?
Since I havnt had any luck finding a proper Quadrajet for my 73' I started looking into rebuilts.
I called Jegs and the guy said "it will work no problem, this has to be
Heres the link to Jegs https://www.jegs.com/webapp/wcs/stor...tegoryId=10271
Take a look and tell me if you think one size could possibly fit something from 190 HP to 400 HP...This doesnt sound possible to me.
Thanks
Bob
I cant understand how they can possibly sell a one size fits all carb?
Since I havnt had any luck finding a proper Quadrajet for my 73' I started looking into rebuilts.
I called Jegs and the guy said "it will work no problem, this has to be
Heres the link to Jegs https://www.jegs.com/webapp/wcs/stor...tegoryId=10271
Take a look and tell me if you think one size could possibly fit something from 190 HP to 400 HP...This doesnt sound possible to me.
Thanks
Bob
Burning Brakes
Joined: Jul 2004
Posts: 1,235
Likes: 0
From: Sick of these TOOLS & AZZHATS in DC
IMO they are pretty nice carbs. I ran a Stage 2 on my 383 stroker during break-in and for about the first 1000 miles while my other Qjet was being rebuilt by Lars. Other than it running a little rich at idle it was great...cruise speed was awesome and WOT was brutal!
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by NC C3
Other than it running a little rich at idle it was great
Im running a stock L48
I cant believe how damn frustrating this whole QJ search is.
I went out and spent $360 on a Holley and it runs great but it is missing the grunt of the QJ...
I have read so many conflicting threads on the QJ that I dont know what the hell to do anymore...
Sorry.... Just venting...
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
You will always get better results from a GOOD build, from your existing carb than buying a rebuild outta the box. All the working parts in your existing carb, have worn in together and fit.
You get a boxed rebuild and you are buying a carb that's built from parts out of bins. You wind up with a carb that has been assembled with parts of a hundred individual carburetors, none of which fit as good as yours do now.
It is HIGHLY unusual for a rebuild to go on a car without issues and half of the time, the rebuild has to go back to the supplyer to be exchanged for yet another one.
Lost shipping $ for you and lots of wasted time.
You get a boxed rebuild and you are buying a carb that's built from parts out of bins. You wind up with a carb that has been assembled with parts of a hundred individual carburetors, none of which fit as good as yours do now.
It is HIGHLY unusual for a rebuild to go on a car without issues and half of the time, the rebuild has to go back to the supplyer to be exchanged for yet another one.
Lost shipping $ for you and lots of wasted time.
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by SanDiegoPaul
You will always get better results from a GOOD build, from your existing carb than buying a rebuild outta the box.
The threads in the check ball hole are stripped...
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
Originally Posted by Bob Onit
That would be great Paul but my core is not rebuildable
The threads in the check ball hole are stripped...
The threads in the check ball hole are stripped...
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by Bob Onit
That would be great Paul but my core is not rebuildable
The threads in the check ball hole are stripped...
The threads in the check ball hole are stripped...
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Originally Posted by Bob Onit
That would be great Paul but my core is not rebuildable
The threads in the check ball hole are stripped...
The threads in the check ball hole are stripped...
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Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
According to QJet documentation that I have read, the Qjet is a variable CFM carb and will adapt to engine demand, so the one size fit's all seems to be somehwat a reality. Jetting however is a different story. I have a Edelbrock 1901 QjET which is running way lean on my car, especially at WOT. I was going to buy the Jet Stage 2 based on recommendations in this forum but Lars and BigBlockk convinced me to get a tuning kit and work with what I have. However what I have is a working carb which has a lean condition at WOT.
According to the description, the Stage 2 undergoes extra testing and calibration, so I would hope it would be a premium carb over a standard rebuilt unit, and that they would stand behind the product. I agree it is a high $$ risk unless you can find someone with first hand experience with it. If I was in the same place you are, I would most likely give it a try provided the return policy was decent.
Hope this helps.
According to the description, the Stage 2 undergoes extra testing and calibration, so I would hope it would be a premium carb over a standard rebuilt unit, and that they would stand behind the product. I agree it is a high $$ risk unless you can find someone with first hand experience with it. If I was in the same place you are, I would most likely give it a try provided the return policy was decent.
Hope this helps.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by Bob Onit
That would be great Paul but my core is not rebuildable
The threads in the check ball hole are stripped...
The threads in the check ball hole are stripped...
Lars
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
You can HeliCoil that and fix it - done that many times...
Lars
Lars
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
Originally Posted by dosoctaves
According to QJet documentation that I have read, the Qjet is a variable CFM carb and will adapt to engine demand, so the one size fit's all seems to be somehwat a reality. Jetting however is a different story. I have a Edelbrock 1901 QjET which is running way lean on my car, especially at WOT. I was going to buy the Jet Stage 2 based on recommendations in this forum but Lars and BigBlockk convinced me to get a tuning kit and work with what I have. However what I have is a working carb which has a lean condition at WOT.
According to the description, the Stage 2 undergoes extra testing and calibration, so I would hope it would be a premium carb over a standard rebuilt unit, and that they would stand behind the product. I agree it is a high $$ risk unless you can find someone with first hand experience with it. If I was in the same place you are, I would most likely give it a try provided the return policy was decent.
Hope this helps.
According to the description, the Stage 2 undergoes extra testing and calibration, so I would hope it would be a premium carb over a standard rebuilt unit, and that they would stand behind the product. I agree it is a high $$ risk unless you can find someone with first hand experience with it. If I was in the same place you are, I would most likely give it a try provided the return policy was decent.
Hope this helps.
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
Just re-rod/re-jet your 1901. All of the parts are easily accessable for less than $20. It only takes like 20 minutes to do it.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
All carbs must be jetted to the engine and to do it right is a pita.
The last one, I had to take apart 11 times to get it right.
Big difference in performance and mileage.
There are also formulas for sizing a carb to an engine and rpm is an important part of it. I'll have to see if I can find it.
The last one, I had to take apart 11 times to get it right.
Big difference in performance and mileage.
There are also formulas for sizing a carb to an engine and rpm is an important part of it. I'll have to see if I can find it.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
How good is a Q-jet's overall performance for HP and TQ assuming its on a medium sized engine and jetted correctly? I mean in comparison to say a 750 Holley or Demon?
The reason I ask is I might be having to do my motor sooner then I thought, it will probably end up being a home built 383" with some decent heads, maybe the trick flow package or something and I might have to use the q-jet for a while since I won't have the extra $400-500 laying around for a Demon. Could I just use the q-jet, jet it correctly and still see decent numbers out of the motor? I think my q-jet is a 750cfm.
The reason I ask is I might be having to do my motor sooner then I thought, it will probably end up being a home built 383" with some decent heads, maybe the trick flow package or something and I might have to use the q-jet for a while since I won't have the extra $400-500 laying around for a Demon. Could I just use the q-jet, jet it correctly and still see decent numbers out of the motor? I think my q-jet is a 750cfm.
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
My understanding is that a completely stock L-48 vette's primary rod/jet size, for a 4ME q-jet, would be a 50 rod with a 73 jet and the CH secondary rods. True duals and you probably want to bump to a 75 jet. True duals with headers and you want to bump to the DA secondary rods. Add in a better cam and you'll probably need 48 or 47 rod. This is what I've found with my L-81, at least. It may not be true with ALL vette engines, though. I'm running 47k rods with a 75 jet and have headers/sidepipes/cam. Hopefully I'll do some new heads in the near future and we'll see what type of jetting I'll have to do then. 
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by dosoctaves
There you go!...Seeing as how you have a working Holly I would go with this advise all they way.
As I still have all the original parts...jets rods..piston ect: It may work.
The only thing that scares me is that when I dissasembled the carb the power piston was stuck in its bore so tight that the rod hanger pulled off the piston before the piston came out
I ran some very fine emery cloth around the bore and the piston now moves freely.. Im just wondering if this will cause problems.
