Enthusiasts either love it or hate it. However, the Quadrajet is easily the most tunable spreadbore out there if you pay close attention to what makes this big-throat atomizer tick. The first round of Quadrajet improvements came in with the APT adjustable part throttle feature, which enabled more finite tuning and a smoother transition from idle to power circuit. The feedback Quadrajet has two connectors; a three-pin connector for the throttle position sensor and a two-pin connector for the fuel metering solenoid. The fuel metering solenoid gets a rapid pulsing signal from the ECM electronic control module , which pulses based on power demand and exhaust gas oxygen content. This is known as electronic mixture control. The objective is cleaner emissions and finite power tuning and fuel efficiency. The throttle position sensor provides throttle position feedback to the ECM.
Rebuilding a Rochester QuadraJet Carburetor
Under the hood, it had a small block V8 engine with a Rochester QuadraJet carburetor. We were too focused on doing body work to worry about the engine at first. In the summer of , I decided to take a look at the rebuilding the carburetor.
Nov 17, · Hello, I’m looking for a little advice. I just dropped a new/Used Rochester quadrajet Carb on my Small block after my Edelbrock went up in flames.
Hooking up the electric choke on an Edelbrock AFB carb. When I first installed the Edelbrock carb with electric choke I had problems with running way too rich, not opening the secondaries and the choke staying on way too long. After I ran out of ideas and the installation manual wasn’t much help, I finally broke down and did the thing we all hate to do: They told me that this was a common problem with GM installations because the stock choke wire does not provide a full 12 volts to the choke coil.
This may be fine for Quadrajet or Dualjet carbs, but the Edelbrock will not function correctly unless it has 12 volts supplied to it. They suggested splicing a wire from the windshield wiper supply wire and running it to the choke. This will work for the connector pictured below, but other types of connectors might be more difficult to tap into. In such cases, it might be a better idea to run a wire from the IGN circuit at the fuse block.
The white wire is the wiper supply line and the red one is the wire I spliced into it. Then I connected the other end of the wire to the “Plus” terminal on the choke assembly.
That individuality combined with corporate policies limiting maximum displacement for different body styles to produce a multitude of different engines of very similar capacities and outputs. By , for instance, Buick, Chevrolet, Oldsmobile, and Pontiac each offered a cu. While Chevrolet, Oldsmobile, and Buick each had distinct small-block and big-block V8 engine lines, Pontiac really had only one.
It had certain features in common with the contemporary small-block Chevy, such as rocker arms pivoting on studded ball joints rather than rocker shafts a feature that had actually been developed by Pontiac engineers and shared with Chevrolet , but it had some significant internal differences. It was also somewhat bigger and heavier than the Chevrolet engine, with greater growth potential. Grow the Strato-Streak did — from cubic inches 4, cc in to cu.
Rochester QUADRAJET 4 Barrel Carburetor Parts USA made carburetor parts for Automotive & Marine Rochester Quadrajet 4 barrel carburetors. Carburetor rebuild kits, Bushing kits, Ethanol Compatible Accelerator Pumps, Jets, Rods, Floats, Gaskets, Needle & .
In trying to get the headlight door motors, I ended up taking out the whole damn front end – grill, bumper, etc. There was just no easy way to get to the door motors. I probably removed 50 bolts out of the front of the thing. Eventually I had half the car in the back of the truck just to get a couple pieces of trim and the headlight door motors, but there’s nothing wrong with a few spare parts.
I have heard since then that if you remove the horn it’s easy to pull the motors right out the top, though the shop manual says you can pull them out the bottom, which is impossible. June the work began. Nathan pulled the non-original wheels off and found that they were dragging on the brake calipers because they were too shallow – good thing nobody tried to drive it!
Chevrolet Performance 350 C.I.D. Base Engine Assemblies 12681429
The 9 cap is available at your local GM dealer. Ask for AC Delco type RC32 part and a 10 cap is available at most autoparts store under a Stant part number , if they don’t have it, have them order it for you. The lower pressure rated caps are not carried by the store much but they are available.
Nov 03, · This video shows how to set the Automatic Choke on a Rochester (Quadrojet) Carburetor with a (small block) chevy Engine.
And over a fairly wide range of RPM and performance. The present iron and aluminum Pontiac intakes are functionally a direct copy of the Super Duty intake. The mounting is different, but the runner and plenum designs are essentially identical. So they are excellent intakes — probably the best of any production passenger car.
The larger engines must move more air, so may not run as effeciently at higher RPM as do the smaller engines with identical intakes. At the time of our initial tests of intakes, I was just looking for the quickest intake with decent driving for my car at that time. But after about the fourth one, I realized that the tests would be of general interste so contacted High Performance Pontiac magazine, who printed the results back in about While the factory aluminum HO intake was slightly slower then the iron, it was a minor amount and most cars would not be able to measure the difference.
I contacted Mac McKeller, who worked on the high performance programs, about the results and he was a bit surprised. But he also reported they never tested nor made a direct comparision between the iron and Al units. As both use the same runner shape and design, they could be expected to run the same. And with the Al unit lighter, perhaps a bit quicker. But it is still an excellent intake and as suitable for use as the iron version..
Quadrajet Electric Choke Wiring
Pretty excited to see if their work holds up to the hype! The new Qjet comes with an electric choke. The current Qjet in my truck has a manual choke “conversion” I’d like to do away with if possible. Does anyone here have any suggestions on a good wire to tap or connector to use? For what it’s worth – I have a lot of options as all of the smog equipment on the truck is missing. It’s a 75 however, with the original manual choke knob, so I don’t think there was every any true electric choke equipment present.
Oct 18, · My motor, intake and Quadrajet carb came from a 79 truck that originally had a 3sp. auto. I’ve put a R4 behing it and I have to hook up the tv cable to the carb. I got a bracket that bolts to the back two bolts on the carb that’ll anchor the throttle cable and the R4’s tv cable.
Be sure to save the illustrations separately. The opinions expressed here are my experiences, and your experiences may vary. I don’t put myself forward as the world’s leading expert on Holleys, but I do have some helpful ideas. In some cases, I may not be able to answer specific questions, but I’ll do my best. I know very little about other brands of carburetors and have no information about them, only general operating principles.
I have NO experience with any type of supercharger or turbocharger, so please don’t ask me anything about your blower or turbo applications. The following few paragraphs is a set of rules I had to create because people were emailing me without enough information or asking really stupid questions that I had no way to answer.
Please follow the post completely for details of the process. Throttle response is not delayed, I expected it to have a delay like most modern fuel injection cars do. Throttle response is as instant as a carburetor. No more high to low engine rev at startup, it starts and stays right at rpm. Best part is, I can change this with the handheld controller. Engine has never ran this consistently cool before.
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Its last application was on the Oldsmobile V8 engine, which was last used in the Cadillac Brougham and full size station wagons made by Chevrolet, Pontiac, Oldsmobile, and Buick. Not widely known, the Q-jet was used briefly by Ford on the Cobra Jet and was also used by Chrysler Mopar on their truck engines in the ’80s. The Quadrajet has been described as one of the best carburetors made for passenger vehicles, offering the best compromise of fuel economy, performance, driveability, and emissions control.
By comparison, a “squarebore” carburetor may have primary and secondary venturis of similar if not exactly the same size and the center to center spacing of the primaries and secondaries are the same, thus the name “squarebore”. Most Quadrajets made prior to were capable of cubic feet per minute CFM maximum air flow measured at a 1. The increase in airflow was due to a larger primary venturi. In Pontiac had designed a special Q-jet that had the most flow of any production Q-jet, but because the modification decreased the vacuum signal on the primary side too much it was discontinued, so it was a “one year wonder” that fetches outrageous prices from restorers today.
Many more cfm Q-jets were installed from up. One way to locate a large casting carb is to source one from an ‘ up light truck. A less-common, early version uses a linkage attached to the primary throttle shaft to mechanically move the power piston. There were also two additional Q-jet designs used mainly in only, that used an auxiliary enrichment system in addition to the primary PP system. There are two types of auxiliary systems: The other uses a vacuum operated PP like the primary PP, but it differs by using only one metering rod and one fixed jet to feed both sides of the primaries.