[carbking]

A comment about the Comp Series TQ was made in another thread which I thought needed additional information; however, rather than hijack that thread, I am posting a thread on the TQ:

Quote:
Originally Posted by GTO-relic View Post

"the vintage Carter Competition Series 1970-74 carbs were a Qjet on steroids with dual floats, dual float bowls, and phenolic center section. If you like the spreadbore design and Qjets in general, find the vintage Carter Comp series and purchase it, and tune it up. you won't regret it. it's identical in venturi, throttle plate design to a Qjet, just much better fuel delivery, and about 50cfm more flow, i.e. 850 cfm. They were advertised as 1000 cfm when new, but that was stretch advertising. it will support a higher level of horsepower than a Qjet will, due to having dual needle valves, one per side, but with the same street driving manners."

End Quote

Carter introduced the Comp Series TQ in 1969 in two sizes: 850 and 1000. These were sold aftermarket only for racing.

Not nearly as many of the 1000's were sold, and they are rarely seen today.

The part numbers were 4846 (850) and 4847 (1000).

Additionally, there was an early and late version of both, the suffix told the story:

4846s - 850 with press-in jets
4846sa - 850 with screw-in jets
4847s - 1000 with press-in jets
4847sa - 1000 with screw-in jets

The early models with the press-in jets have a sealing O-ring, similar to the O-ring used on some Holley fuel valves.

In 1971, MoPar 340 performance engines got 800 CFM TQ's

In 1972, MoPar 340's continued with the 800, and 440's got 850's.

There were a few 1972~1973 700's built for California vehicles.

By 1980, ALL O.E. applications were 520 CFM. However Carter was still producing aftermarket performance 800's.

I agree completely with GTO-relic that running one of the Comp Series is worth considering (I have an 850 on my own GTO).

However, in full disclosure:

There are four separate and distinctly different generations of the TQ:

(1) 4846s, 4847s
(2) 4846sa, 4847sa
(3) 4972s, 4973s
(4) EVERYTHING ELSE

There is some interchangeability from generation 1 to generation 2
There is virtually no interchangeability of generation 3 to any of the others.

Parts for generation 4 (other than rebuilding kits) are difficult.
Parts for generation 3 are extremely difficult
Parts for generations 1 and 2 are very difficult

With all generations, money talks when it comes to parts.

I have personally never tested the Comp Series for air flow, but I have no reason to doubt Carter's ratings. Until F/M took control of Carter, their advertising was quite conservative.

I have personally NEVER had enough engine to run one of the 1000's, but the 850 on my GTO runs great.

Jon

[carbking]

Seems I NEVER get all the information in the first post.

The Carter performance street 800's were 9800s and 98010s (GM and MoPar) with no EGR port; and 9810s and 9811s (GM and MoPar) with an EGR port and a plug if the port was not needed.

When F/M took over Carter, F/M shut down the Carter refurb plant. As a distributor for Carter, we, like others, were offered the inventory. I bought every single performance carb in their inventory. Since then have sold maybe 500 of the 800 CFM primarily for street engines, many to Pontiac enthusiasts, although some folks use them on trailered race carbs. We sent one to Jim Hand for testing, and the results are contained in Jim's book.

While Carter suggested the 800 CFM for the Pontiac 400 CID engine; we have sold several to Pontiac folks with 455's, many of whom are repeat customers.

I had an 800 on my GTO, until I got tired of it stalling at every stop sign until warm (*&^%$ automatic choke, my "heel and toe" ability is less than it was 50 years ago). I replaced the 800 with the 850 because the 850 came with a manual choke. The manual choke solved the issue. Basically a case of building too radical an engine for the street! Bet I am not alone in this concept!

Jon

[P@blo]

Thanks for posting the TQ information Jon. I am about to try a 850 cfm version myself and was wondering what the best approach is for the choke.

My plan was to flip my divorced choke coil so it pulls down when warming but may go the manual choke route. Also having problems trying to figure out my th350 kickdown cable as well as the TQ throttle does not have the arm needed. Probably end up making a bracket or something.

Did you make any modifications to your 850 or do you run a factory configuration? Not sure if there will be anything needed for my warmed over 400 as the original application was a 73 440.

[Jay S]

Jon, since you mentioned the choke, has there ever been a electric choke option for a thermoquad?

I am still piecing together the 72 thermoquad I talked to you about probably more than a year ago now, I recall talking to you about seeing what you had for a strip kit for it. I found out for that racing class the only limit is the throttle plate size has to match up the factory size so we just started with an 850 of a later 440 Mopar. Should have it going later this year, big project. Been looking for one of the 1000 cfm performance carbs like you listed to try eventually since the throttle plates still match up.

I enjoy your Carter tech info.

[carbking]

Pablo and Jay:

The MoPar o.e. carbs used a divorced automatic choke like the earlier Q-Jets. I have never really compared the choke operation on an o.e. carb to the choke operation on a Q-Jet. If one "pulls" and the other "pushes", this is not an issue; simply think outside the box. Consider a child's see-saw a.k.a. teeter-totter. The assembly consists of a fulcrum (the pivot), a lever (the board), and two masses (the 2 kids). When one kid goes up, the other kid goes down. Simply fabricate a pivot and lever assembly to change the direction of the choke rod.

The Carter "street performance" 800 CFM TQ's came with an electric choke; carb numbers 9800s, 9801s, 9810s, and 9811s.

I have never tried to marry one of the o.e. carbs and one of the performance carbs to acquire an electric choke.

I have never tried to marry one of the Comp Series TQ's to an o.e. carb to acquire a manual choke.

I am running the 4846sa (850 CFM) with the original Carter calibration on a too-high-performance-for-the-street Pontiac 350.

For the 1000 CFM carb, you might try that grumpy old Missouri hillbilly.

One other comment on the TQ's: the post-1975 o.e. MoPar carbs were calibrated lean for emissions. To comply with the EPA's request to minimize "tampering", this often was done using large air bleeds. The rationale being any enthusiast with a screwdriver could replace jets; but fewer enthusiasts have the where-withal to pull air bleeds, machine new ones with a smaller orifice, and install them.

Jon

[JLMounce]

I had a couple 9800s's on a spread bore offenhouser 360 years back. Ended up giving both carbs away, but in hindsight it was a cool setup. Gave one of the carbs to a friend and Ray Klemm received the other to hopefully bring back to life for somebody in the future.

Both were 9800s models setup on a linear linkage. Neither had chokes if I recall, but the car came with the setup, so I can't say for certain if they ever did.

[77 TRASHCAN]

Originally Posted by JLMounce

I had a couple 9800s's on a spread bore offenhouser 360 years back. Ended up giving both carbs away, but in hindsight it was a cool setup. Gave one of the carbs to a friend and Ray Klemm received the other to hopefully bring back to life for somebody in the future.

Both were 9800s models setup on a linear linkage. Neither had chokes if I recall, but the car came with the setup, so I can't say for certain if they ever did.

Is Ray restoring carbs, now??? What is name of his business, if so...?

[carbking]

Originally Posted by JLMounce

I had a couple 9800s's on a spread bore offenhouser 360 years back. Ended up giving both carbs away, but in hindsight it was a cool setup. Gave one of the carbs to a friend and Ray Klemm received the other to hopefully bring back to life for somebody in the future.

Both were 9800s models setup on a linear linkage. Neither had chokes if I recall, but the car came with the setup, so I can't say for certain if they ever did.

I have a new old stock manifold that I bought to put the set-up on my 350, then decided the fabrication of the sheet metal to connect the 2x4 to the shaker was waaaaaaay above my capabilities.

Jon

[JLMounce]

Originally Posted by 77 TRASHCAN

Is Ray restoring carbs, now??? What is name of his business, if so...?

Don't quote me on this, but I believe Ray purchased Cliff's assets when he got out of the rebuilding business.

I don't know if he has a company name or works completely off of referrals. He's on instagram, facebook etc. If somebody is looking for a 9800s, he may still have the one I gave him that could be rebuilt.

As far as my old 2x4 setup, the offenhouser (not marked 360) had what appeared to be two fabricated spreadbore base plates on the individual plenums. The manifold was fairly old, so I figured it was originally setup for spread bore. It's possible it was a slight custom deal.

I sold that manifold to Half Inch Stud many years back. He might have some information on it.

[NeighborsComplaint]

I had a factory Thermoquad on a '72 Dodge Demon 340 I bought used back in the mid-70's. It was a great performing carburetor (and car) with one tic. The secondaries were locked out until the engine reached full operating temp. I believe a solenoid on the linkage blocked the air door and was activated via a thermostatic switch on the thermostat housing. Even luke-warm, the secondaries were locked out. Once at operating temp, the carb functioned normally.

[70GS455]

I ran a Tquad on my car on the street for many years. Back in the day you could get an aftermarket ekectric choke coil which is what i used and worked well.


I dynoed a modified production 850 Tquad and it made 590 hp, 611 ft lbs. It started out life as a 6322, the outer booster ring was removed and the plastic bowl venturi hump was removed. Took lots of tuning

Sent from my SM-G991U using Tapatalk

[Jay S]

Originally Posted by 70GS455

I ran a Tquad on my car on the street for many years. Back in the day you could get an aftermarket ekectric choke coil which is what i used and worked well.


I dynoed a modified production 850 Tquad and it made 590 hp, 611 ft lbs. It started out life as a 6322, the outer booster ring was removed and the plastic bowl venturi hump was removed. Took lots of tuning

Sent from my SM-G991U using Tapatalk

That is cool! I talked to Jon about doing the same thing with a somewhat similar carb I have, off a 72 400 Mopar, requiring a strip kit for tuning, and I believe he suggested converting it to a bigger fuel line and higher flow needle and seats. Maybe not exactly the same, would have started as the same cfm as a 6322. 6322 TQ IRC would have started out as a 850 cfm off of a 73 440, with those mods described it should have be close in size to one of the 4847 competition 1000 cfm carbs. Pretty amazing that much flow is possible out of a big TQ. Being that we are not married to particular carb part number, kind of decided the 1000 cfm 4847 makes the most sense, 542 cid with 318 cfm heads. I am curious about the engines low end manors without the outer boosters and Venturi hump removed in a street car? Like say in a 542 that had A/C

[Tom Vaught]

I still have the 850 TQ you sent me, Jon, many years ago, if I could remember the "safe place" I put it.

Tom V.

[carbking]

Tom - without looking, memory says it was an 800 rather than an 850.

As far as remembering where you put it?

Grandchildren are life's exchange for growing older and beginning to lose one's memory!

Jon

[70GS455]

Originally Posted by Jay S

That is cool! I talked to Jon about doing the same thing with a somewhat similar carb I have, off a 72 400 Mopar, requiring a strip kit for tuning, and I believe he suggested converting it to a bigger fuel line and higher flow needle and seats. Maybe not exactly the same, would have started as the same cfm as a 6322. 6322 TQ IRC would have started out as a 850 cfm off of a 73 440, with those mods described it should have be close in size to one of the 4847 competition 1000 cfm carbs. Pretty amazing that much flow is possible out of a big TQ. Being that we are not married to particular carb part number, kind of decided the 1000 cfm 4847 makes the most sense, 542 cid with 318 cfm heads. I am curious about the engines low end manors without the outer boosters and Venturi hump removed in a street car? Like say in a 542 that had A/C

Low end nanners were not that wonderful. I have not driven it, only dyno time. But idle was the worst of 3 carbs, mid range was poor, and it wouldn't roll into the start of the test (3200 rpm) very well. That being said, it did however make within 5 hp of a Holley HP Ultra 950

Sent from my SM-G991U using Tapatalk

[carbking]

Originally Posted by Jay S

That is cool! I talked to Jon about doing the same thing with a somewhat similar carb I have, off a 72 400 Mopar, requiring a strip kit for tuning, and I believe he suggested converting it to a bigger fuel line and higher flow needle and seats. Maybe not exactly the same, would have started as the same cfm as a 6322. 6322 TQ IRC would have started out as a 850 cfm off of a 73 440, with those mods described it should have be close in size to one of the 4847 competition 1000 cfm carbs. Pretty amazing that much flow is possible out of a big TQ. Being that we are not married to particular carb part number, kind of decided the 1000 cfm 4847 makes the most sense, 542 cid with 318 cfm heads. I am curious about the engines low end manors without the outer boosters and Venturi hump removed in a street car? Like say in a 542 that had A/C

We have sold several of the 4847s carbs to be used on the street. Only one customer was super happy about the idle; but above idle ALL were happy.

As to modifying another to think it is a 4847s, I don't know; have never had any experience with that.

I do know the 850 (still has the booster ring) runs like a scalded dog on my Pontiac 350 on the street.

And it will idle at about 900 without the choke after about 30 minutes. NEVER again would I consider blocking the heat passages on a street engine.

Jon.

[carbking]

Tried to edit the above post, but system would not let me do so. Below is the edit:


EDIT: had an appointment, so didn't finish this post. Remember that the 4846 and 4847 were designed for RACE only. Carter totally redesigned the circuitry of these carburetors when Chrysler wanted to use them as O.E. in 1971. And the circuitry was again redesigned for the 1972 models, and this design used to the end. Without studying the circuitry, not sure how modification of the airflow on the later carburetors would effect driveability. MUCH easier to tune a carburetor for WOT only than calibrate it for good street manners throughout the RPM range.

Jon

[Jay S]

Thanks for the insite. The only thing that makes me question how well a 1000 cfm 4847 without the outer boosters will work is when running the A/C on the 542. Giving up idle quality to run the 1000 cfm carb with out the outer boosters and trying to run the A/C on the street maybe isn’t a good trade. Maybe an 850 for normal street driving and the 1000 for when we want to “go for it”.

We run several thermoquads. My favorite one was a 850 cfm from the mid 70s, don’t recall the number anymore. It burnt up while on the car years ago, parked it in the shop, but came out the next day and all the was left was the throttle plates and the top. Bowls nearly completely melted, still amazed there was no damage to the car other than loosing the carburetor. Not even paint damage on the hood. It was on our 71 Chevelle at the time, it had a terrible time running on after it was shut off. I think it backfired after it ran on and caught the carb on fire. Previously we had that 850 TQ on our 69 Charger with a 510 cid and 3.23s, about 500 HP. My brother drove it to the Kansas City dragstrip and averaged between 17-18 MPG (340 mile round trip). He finished second in a pro class, that mpg was INCLUDING all the 1/4 mile passes. I think he made 11 or 12 quarter mile passes that weekend that was averaged into that fuel economy. Even full throttle they seem to do well on fuel. My dad drove our 15 second 65 Dodge Dart GT down that same weekend with one of smaller the 800 cfm TQ’s with a washed up 318 cid and 3.23s, it averaged in the lower 20s on the trip. I have not been close to those MPG numbers with any other carburetor other than a TQ. I can get close with other carbs (Holley’s, qjets) for a check between stations, but for a long trip average the TQ seems to be king. I think it comes from the gas in the bowls staying colder.

[carbking]

Jay - the fuel running cooler makes a measurable difference, but just barely.

Carter had an independent laboratory run tests on the fuel temperature back in the day; and the figure arrived at by the laboratory was 25~30 degrees, with an average of 28 degrees.

Conventional wisdom says that a 10 degree drop in fuel temperature in the carburetor will translate into a 1 percent increase in efficiency. So based on the Carter figures, you might get 3 percent increase.

I would rather think the increase is due to superior A/F figures.

Just for the record; with the 800 CFM (before I tired of stalling at stop signs for the first 30 minutes, and replaced it with the 850 and manual choke) installed on my 350 Pontiac for BREAK-IN, I poured 5 gallons of race fuel into the tank. Did the 20 minute cam break-in, then around town, and some 65 MPH highway, with occasionally "spurts". Forgot about the fuel (did not have the fuel gauge working) and ran out (luckily, in my driveway) with 99 miles on the odometer, which is calibrated.

Jon

[carbking]

The biggest disadvantage of the TQ is slowly going away; that being easy access to parts.

Up until a couple of years ago, you could get Holley tuning parts in every FLAPS in the world. Today, both my FLAPS don't even carry mounting gaskets. So the Holley advantage is disappearing locally.

Parts for the TQ, the Q-Jet, and the Holley are still available mail order. There are still more vendors that carry part for Holley than for the Q-Jet, and more vendors that carry parts for the Q-Jet than for the TQ; but the vast chasm has narrowed.

Jon.