Why don't more people use Quadra Jets???

Let me start this post off by saying that I don't know anything about the Rochester Quadra Jet except what I've read in David Vizard's books. From what I've read though, the Q-Jet seems like the ultimate carb for a daily driver... small primaries for cruising, and monster secondaries for when you mash the gas... kinda like having your cake and eating it too.

So why aren't they more popular?

They're abundant at the junkyard and possibly already on the project car you just picked up. Why are rodders so quick to replace it with a Holley?




Ed

 

SHHHH!!
Keep it a secret, so my core costs stays at the high of maybe $5 down to the usually free that I get mine for

 

well i can speak for the "everybody" in your statement , but i find they run awesome when tuned but are a total ***** to get them to that well tunned state of perfection . And even tougher when you go through things like elevation change. I think more "mainstream" hotrod people are getting away from carbs alltogether and i am seeing more tpi and fuel injection set ups . Now traditional is another story .
In short ,I found a really nice tunned q jet is a great thing but getting it there well ... holley and edelbrocks are just plain easy . The newest holley line the street avenger is the fastest tune yet 3 turns of 2 screws and done . DrJ is right , and if you can tune a q-jet to perfection everything else is easyyyyy .

 

There was quite a good article about it in Street Rod Builder (or something like that) a couple years ago. They touted the same merits as you did and more, economy, drivability, performance (up to a point). One of the drawbacks they mentioned as I recall is a relatively small float bowl capacity for high performance use as well as not being as easy to work with, more dis***embly required, to make performance tuning changes.

I had always heard them called Quadrajunks. One problem I recall personally is a hot-restart flooding problem, but I believe there are simple fixes to that. I'd consider one for the benefits mentioned on a mild performance street application.

 

Most of the "knowledge" guys spout out, whether Holley,QJet or Carter comes from dufus' (dufi?) that have never bought anything more than a worn out swap meet piece of ****. GM didnt install millions of QJets cause they ****. Holley isnt still in business cause the carbs are ****. Carter/Edelbrock seem to still be in the black? Hmmmmmmmmmmm, sense a trend?

 

there is a guy here that held an NHRA record several years in a SB 67camaro.
He is rumored to be a QJ spe******t and can modify one to any level of performance you need...was thinkin he got 350 dollars each for em.
he is at Macon Missouri.[VAL HEADWORTH -formerly Calif.]
I will say that if a Q-J is a good one it will run excellent.some of the big Caddys Buicks and Oldses had 750 thru 850CFM...

seems the most prominent weakness is leaking bowl syndrome [where the FACTORY epoxy patch has cracked]

 

Edmurder, the answer to your question (aside from the fact that no one knows if quadrajets outnumber all other brands added together) --the answer is that Holley and Edelbrock ADVERTISE, Quadrajet doesnt. You see Holley advertised EVERYWHERE. If you compare the cost of a quad rebuild kit ($20?) to Holley-($80?) quads look good

 

The Q-Jet is mostly just "Mis-Understood".
The Performance of this unit is as impressive as any
other carb on the market. It is often overlooked as many folks believe that the "other-brands" are easier to tune.
There are hundreds on NHRA / IHRA drag cars that run ET's in the 9's and up with these units.
As you have stated, Visards book sheds the light, all you have to do is follow the instructions.
The benifits in quick throttle response, excellant drivability, fantastic fuel mileage, and awesome HP are all available with the Q-Jet.
And yes, I can find them at the local swap meets for $5 bucks all the time.
No need to hunt down special 800 CFM units, the normal 750 cfm units properly tuned are more than suficiant for engines up to 850 HP. Just ask anyone that runs a A - B - or C cl*** Super Stock car / engine combination.

 

Yes the Q-jet is the most underrated carb of all time. I love 'em! I would like to someday see 2 q-jets on a tunnel ram manifold. You would have driveabilty,on the street, and ungodly CFM's when the need for afterburners arises! Not as efficent as FI,but affordable for us backyard types. This summer I'm putting one on my rod,and will relay the results. Now if I could find a tunnel ram for a sbc cheap. Maybe some street rodder,who's updating to FI, could "throw 'one away in my direction?? Sparky

 

Oh I forgot one of the details on this guys NHRA record holder....it wasn't equipped with a Qj- it was a 327" two barrell carbed car!=10 seconds=1/4 mile......

 

I'll run the pro built QJ on my 396 against a Holley any day.
Another will be going on a 351W in my E350 box truck so I can get up the hills a bit easier but not **** the tank dry on the flats.

Holley tried to compete with their "Spreadbore" which ****ed.

There are pre smog and smogger QJ's so be sure you know what models to look for. There is plenty of info on the Web.

 

One more note of information.
Magnelli-Merelli who manufactures the new Q-Jets for Edelbrock has just distroyed the tooling due to lack of business volume. So, if you want a NEW Edelbrock Q-Jet, you had better get yours ordered Monday.

 

They work great, but are just too damn UGLY. There..I said it.

I'm a function first, looks later kind of guy, but geesh..These things are too knarly...

-Abone.

 

I've always had really good luck with the Q-jet but I wanted a killer Q-jet for my 355 chevy. I'd just built it from a 77 Camaro winter beater engine and dropped it in my 49 ford coupe with a kitted 350 turbo.
I bought HP Books "Rochester Carburetors" by Doug Roe and Bill Fisher. I'd already scored a big box of old Q-jet carbs and loose parts at the swap meet [$5] so I used the recommended good-guy jets and metering rods from the core carbs to build the mother of all carbs. I also epoxied the well plugs when building the carb as per instructions in the HP book.
This thing ran like a bat outta hell but my fuel tank was rusty and I found out how sensitive a Q-jet is to dirt. I learned how to take the top off a Q-jet in the I-80 rest areas between DesMoines and Omaha when it floods due to dirt between the needle and seat. I learned the hardware store epoxy won't stand up to gasoline very long.
Yes, I learned a lot about Q-jets that summer. I still have the book and my son asked me the other day if I wanted a box of his old Q-jets. Sure do...

 

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I'll run the pro built QJ on my 396 against a Holley any day.
Another will be going on a 351W in my E350 box truck so I can get up the hills a bit easier but not **** the tank dry on the flats.

Holley tried to compete with their "Spreadbore" which ****ed.

There are pre smog and smogger QJ's so be sure you know what models to look for. There is plenty of info on the Web.



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Lookie! Carl is back! You musta recuperated. Good to see ya!

 

Yeah...welcome back, ya old fart.

 

When properly set up the Quadrajet IS just about the perfect all around carb. You have to get an early (pre electronic) one to apply it to hot rodding. When the set-up is right all you have to do is fine tune the secondary tip in to make a seamless transition to WOT. This is done with a set screw and allenscrew adjustment to the secondary air velocity valve (the large flap valve over tne secondary throttle plates.
The drawback for the traditional built car is that they are considered too modern in appearance to fit the era. It boils down to what means more to you, looking correct or having great drivability. You can accomplish this with the older carb setups but most don't have the knowledge or patience to stick with it until you have your cake and eat it to.

Frank

 

I think Quadrajets are kinda like the 6:00 news, all you will ever here about is the bad news stories.I found, you can take about any of these carbs, that are not toally worn out,shafts ect., re-seal the epoxy areas, install a new choke pull off valve, and invest in a rebuild kit,a couple of hours of your time, and your gonna have yourself a decent carb for many miles.It will perform decent and get decent mileage,a good street carb.

 

I've alway's liked the way they run, once tuned..
I spent a lot of time years ago messing with them..
couldn't afford a new Holley back then, so made due with what i had.

The looks on an open engine car are thier only downfall imo.

 

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There are pre smog and smogger QJ's so be sure you know what models to look for. There is plenty of info on the Web.


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got any sites you'd suggest to start with?

 

You can beat more unwitting street racers with a Q-jet than a Holley. The ultimate sleeper carb.

They can be modified to flow 1050 cfm.

I think it's the lack of knowledge on how they work that makes them so unpopular. Not to mention if most people see a fast car with a Holley, to them, the Holley will automatically become the only carb that is a performance unit.

The Quadrajet is the most sophisticated and underestimated carburetor ever made.

I've got 2 words for those who doubt it: David Vizard

 

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got any sites you'd suggest to start with?

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His site has been down for sometime now. (www.davidvizard.com)

His book 'carbs and intakes' has a section on the Quadrajet, which is required reading for the performance-minded Q-jet user.

http://search.barnesandnoble.com/booksearch/isbnInquiry.asp?userid=ba6MjEeAfl&sourceid=00412886846241781605&bfdate=12%2D26%2D2004+00%3A16%3A42&isbn=1884089143&itm=2

 

THANKS!

 

Great carb as you've probably heard. There's one guy in town that is a wizard with those things. I still kind of fumble with them, can't get them perfect, yet. I'll be running one on one of my Nailheads after the new year.... can't wait..

 

OK - lemme go against the grain here if no one else will. As has been eluded to, they can be a ***** to get set up right. That's reason #1 why folks toss them. But, like Holley & Edelbrock, once you learn the secrets, they're not that hard. They are still a pain in the *** to open up.

They're much more sensitive to dirt than Holley/Edelbrock(Carter).

They are UUUUGGGLLLY!

They are also known as Quadra-BOG...

They are prone to flooding on hot-start w/wo the well-do***ented epoxy leaks.

But like I said in the beginning, it's all what you're used to tuning...anyone can get one running, it takes a genius to get one running well, & it takes a prodigy to get one truly tuned to perfection


Gimme my inefficient Holley - I'm lazy

 

AHotRod said it all, these things idle great and get great fuel mileage running around on the small primary bores and give you a kick in the *** you can really feel when the HUGE, mechanical, secondaries get slammed open. Just seal the bowl plugs up good before you put it together and never any problems.

 

Hey...
I'm run'n a 455 Pontiac in a 30 Ford, We built a tunnel ram and used 2 Q-Jets that were mild'y modified and a solid rebuild. I was not a big Q-Jet fan but the cost of the Q-Jets over the "other brand" was the factor. I've had this set up on the road for 3 years with the only problem being dirt and **** get'n into carbs. Put a Fram race filter on and that fixed that.
I'm well pleased and have no complaints at all...Not the sharp'est look'n carbs but they work! Give um a chance
Pontiac Slim

 

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got any sites you'd suggest to start with?

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Give the Buick V8 board a try.

There's a lot of interesting and serious engines being put together by folks on the board and a lot of them use the Q-Jet.
The great majority of them not for the stock cl***es.

1147 posts on the Q-Jet

The above will get you to the home page.
Scroll down to the engine tech section then click on, "The Mixing Shop."

As somebody mentioned, the Q-Jet is a great sleeper carb.
Works great on top of a sleeper Buick 455 . . . everybody knows those don't run....

 

Always loved the sound of kicking down a Q-jet. Sounded like it was going to **** the hood in.-MIKE

 

Damn, I use 'em all the time!

Many a door would've slammed shut in the breeze had it not been for the presence of an old Quadrajet!



Ha Ha Ha...actually, just like the Carter Thermoquad...they're damn near unbeatable when set up right...and cheap as hell to boot!! The secret is out, Man!!