Dyno results - Tquad vs Holley vs Qjet - tuning issue, too rich

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Hysteric said:
Thanks for those pics Rumble.

I've searched the internet for a long time but could never find any pics of the circuitry of the earlier emulsion style Carters. These are very different to the solid fuel type carbs they later produced.
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The electric choke TQ and the first OE year is like this. Strip kits are a small fortune. I have no Holley jet to see if I can tap the jet hood to use the Holley jets. The secondary side would be more of a trick.
lemondana said:
"rumblefish360" I have several of the 156-202 3/8" 90 degree fittings that you need without having to drill anything without having to use that TQ fitting. I think!
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Thanks but it’ll be easy to drill it out. No big deal really. I’ve drilled other fitting for other TQ’s I have. Fittings are available new. The dual fitting so far doesn’t bother me. I think there is plenty of room to make any needed bends in the fuel line.
 
nice carb Fish. number stamped on the ear of throttle plate, rear of carb left side will tell you what size carb it is just like all TQ's are identified this way.
 
ch1ll said:
nice carb Fish. number stamped on the ear of throttle plate, rear of carb left side will tell you what size carb it is just like all TQ's are identified this way.
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Thanks! Sold to me by Demonsizzler.
As far as the stamped numbers, yes, Except the race carbs. I’ll double check the electric choke 800 cfm replacement units tomorrow.

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the one I have is stamped. it would be 4846S or 4846SA for the smaller carb and 4847S or 4847SA for the larger one.
 
I'm typing as you are posting pictures. I see the unstamped ear. I could only guess this carb is one of the first produced like in 1969 or 1970 before Chrysler started using thermoquads on their muscle cars in 71. from what I understand the competition series carbs are different than the 71 production carbs even though both are air metered carbs. the 71 and 4847 carbs are the only TQ muscle car carbs missing from my collection.
from my understanding, the Competition Series carbs do not make good street carbs.
 
I’ll state that my time with there use (replacement units) was really good and trouble free. Having them on a 360 & 400, the small primary was a little restrictive on the 400. It was fine in the 360. Both were mostly stock (AKA - No cam change) engines with bolt on parts. The electric choke was a great item to have on them. One wire and done.
 
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rumblefish360 said:
I’ll state that my time with there use (replacement units) was really good and trouble free. Having them on a 360 & 400, the small primary was a little restrictive on the 400. It was fine in the 360. Both were mostly stock (AKA - No cam change) engines with bolt on parts. The electric choke was a great item to have on them. One wire and done.
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Do the 1000s with the single booster have a longer booster? In other words, is it different than the production 850 double booster with the outer ring removed?
 
70GS455 said:
Do the 1000s have a larger top opening to match the larger 1.5" venturi? Or is there a step there?
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I don’t think so. There is some room for modifications though.
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Hard to tell from the pics, but is the top of the plastic bore the same diameter as the aluminum opening? With your finger, do you feel an edge or is it smooth?
 
LMAO, I do not have tiny fingers, these are not perfect carbs. Perhaps enlarging this ***** can reveal something?
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If you were to take the top off and measure the primary opening ID in the top where it mates to the bowl, what would that measure? Might be easiest to measure the top gasket opening, if you have that
rumblefish360 said:
I don’t think so.
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So, got some semi final results. Its semi final because we didnt finish, a mechanical failure prevented me from testing one last carb. But will finish in the coming spring. To recap and clarify, used a 950 Holley Ultra HP 0-80805, an Everyday Performance prepped Stage 2 800 cfm Qjet and a "950" Thermoquad, modified by Steve Stills and final tuned by me. The Tquad is called "950" (by me) for lack of any better label. It started out life as an OEM 6322 production 850 with 1.5" pri butterflies, but the primaries were modified by removing the stock 1.186" bowl venturis, opening them up to almost 1.4" and removing one booster ring (the idea is to get close to a 1000 CS Tquad using more available fuel-metered cores)

All 3 were without any air cleaner base or air turbine, choke flap hardware was removed.

Holley 595 hp, 622 ft lb
Tquad 590 hp, 608 ft lb
Qjet 586 hp, 604 ft lb

20210128_151127_001.jpg
 
Wow! I’m impressed that your not knit chasing this down but really trying to prove each carbs worth. IMO, the big problem with the TQ is air entry into the carb and down the barrels. The choke tower, just getting air in the secondary side isn’t so smooth. I know each carb would benefit from getting the air in as straight downward as possible.
(Engine Masters “Salad Bowl!” LMAO!)

On the TQ, did you remove the choke rod linkage that runs across the secondary side?
 
70GS455 said:
Recently finished a dyno session on a 482 stroker using a Holley 950 HP ultra, Ken Manley prepped 850 Tquad, and an Everyday Performance prepped 800 Qjet. The big holley gave best results, 595 hp and 622 ft-lb at peak. The Qjet was not far behind, 586/603. The Tquad made 572/597, with a significant calibration issue.

We could not get the Tquad lean enough at WOT. AFRs were below the 10:1 equipment limit, the motor would drown and stumble from the fuel, BSFCs were high, and fuel flow rate was at 286 lb/hr, up from 239 with the QJ. We are pulling over 2" of vac at 6000 rpm, so its somewhat air starved but making decent power.

The sec air door was fully open @ .940", sec butterflies open to 90 deg, leanest sec jets I had at the time of .131, primaries at .095 with 2002 rod, secondary hi speed air bleed opened to 0.041, idle fuel feed at .039, idle air bypass restriction at .043, idle air bleed left alone, primary hi speed air bleed left alone at .080", squirters enlarged. Idle and low speed are great, with a 236/244 cam on 113 LSA. Spring is clipped.

I have since acquired a set of .125 sec jets, and modified a surplus set to accept some screw in primary jets. I have a strip kit.

In addition, I plan to enlarge the primary venturi in the bowl to 1-3/8", and leave the double boosters.

This carb shows promise with decent numbers even though its pig rich. Anyone else run into this?
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ALTHO I RUN A FUEL INH SET UP , THAT`S SOME GOOD DOWN TO EARTH INFO RIGHT THERE !
 
70GS455 said:
It started out life as an OEM 6322 production 850 with 1.5" pri butterflies, but the primaries were modified by removing the stock 1.186" bowl venturis, opening them up to almost 1.4" and removing one booster ring
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Did you measure the vacuum signal before and after to evaluate what that change made to when the primary booster begins to draw fuel?
 
rumblefish360 said:
Wow! I’m impressed that your not knit chasing this down but really trying to prove each carbs worth. IMO, the big problem with the TQ is air entry into the carb and down the barrels. The choke tower, just getting air in the secondary side isn’t so smooth. I know each carb would benefit from getting the air in as straight downward as possible.
(Engine Masters “Salad Bowl!” LMAO!)

On the TQ, did you remove the choke rod linkage that runs across the secondary side?
Click to expand...
I'm curious do you think a good ram air system would mitigate some of the air entry problems
 
70GS455 said:
So, got some semi final results. Its semi final because we didnt finish, a mechanical failure prevented me from testing one last carb. But will finish in the coming spring. To recap and clarify, used a 950 Holley Ultra HP 0-80805, an Everyday Performance prepped Stage 2 800 cfm Qjet and a "950" Thermoquad, modified by Steve Stills and final tuned by me. The Tquad is called "950" (by me) for lack of any better label. It started out life as an OEM 6322 production 850 with 1.5" pri butterflies, but the primaries were modified by removing the stock 1.186" bowl venturis, opening them up to almost 1.4" and removing one booster ring (the idea is to get close to a 1000 CS Tquad using more available fuel-metered cores)

All 3 were without any air cleaner base or air turbine, choke flap hardware was removed.

Holley 595 hp, 622 ft lb
Tquad 590 hp, 608 ft lb
Qjet 586 hp, 604 ft lb

View attachment 1715679874
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Thank you for a very cool thread!
 
K.O. SWINGER said:
I'm curious do you think a good ram air system would mitigate some of the air entry problems
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A good Ram air system helps. How much and to what degree I do not know. But I would call it “Better than none.” The real trick is getting the air to move smoothly into the carb. Under pressure or not. Air is a gas that doesn’t like to make turns. It doesn’t like to go around obstructions.
 
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