For those who have used/using a comp series Thermoquad

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Bewy

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I have 850 CS TQs, one with screw in jets, one with push in jets. Both have a brass tube in the rear of the carb for the air valve diaphragm hose. This brass tube has a very small hole in it, about 0.015". It severely restricts the release rate of the diaphragm & therefore how quickly the AV opens. I would think this would be limiting on a big inch engine. My understanding is these CS carbs were the very first TQs. The later production 6000 series carbs that I have seen just have a steel tube in the carb rear for the AV diaphragm, no restrictor, the restriction being a small hole [ larger than 0.015" ] in the diaphragm hose nipple. Seems odd that a performance carb has a device to restrict airflow but production model does not. I have only seen two other TQs that had the brass tube, both 9000 series. One was for an Aussie Ford. There were 5 Aussie models, 9071, 9085, 9091, 9092 & 9333, used on 302-351 engines. The 9333 has the brass tube, others have the steel un-restricted steel tube.

Has anyone done any mods on the brass tube, enlarging the hole? Did performance improve? Any info welcome.
 
I believe the air door or valve is adjusted by the adjusting screw on the vacuum diaphragm.
 
I have a NOS 1000cfm, CS Thermoquad. I gave it to a friend of mine who does a lot of the S and SS guys cars. He did a buttload of mods to it, to make it a true competition carb. It's 1 to 1 on the linkage, he made screw-in jets [a set] for me, and added adjustable air-bleeds. He's a Chevy S/S racer, but loves Therrnoquads. He says they're a world better than the stock and super-stock Q-Jets. We dyno'd a large modified 4150 Holley, Q-Jet, and the Thermoquad on a 500 inch BB Chevy. With incorrect manifolds for them, the Holley made 20 more than the Thermoquad, and the Q-Jet had another 20 less.

We're gonna dyno my new SB mopar with a Dominator and the modified Thermoquad, to see what I'll be giving up. Should testing in April.
 
Love hearing TQ stories, but would like info on my specific question if anybody has some.
 
MMissile said:
I have a NOS 1000cfm, CS Thermoquad. I gave it to a friend of mine who does a lot of the S and SS guys cars. He did a buttload of mods to it, to make it a true competition carb. It's 1 to 1 on the linkage, he made screw-in jets [a set] for me, and added adjustable air-bleeds. He's a Chevy S/S racer, but loves Therrnoquads. He says they're a world better than the stock and super-stock Q-Jets. We dyno'd a large modified 4150 Holley, Q-Jet, and the Thermoquad on a 500 inch BB Chevy. With incorrect manifolds for them, the Holley made 20 more than the Thermoquad, and the Q-Jet had another 20 less.

We're gonna dyno my new SB mopar with a Dominator and the modified Thermoquad, to see what I'll be giving up. Should testing in April.
Click to expand...
Can you show us the adjustable air bleeds?
 
Bewy said:
I have 850 CS TQs, one with screw in jets, one with push in jets. Both have a brass tube in the rear of the carb for the air valve diaphragm hose. This brass tube has a very small hole in it, about 0.015". It severely restricts the release rate of the diaphragm & therefore how quickly the AV opens. I would think this would be limiting on a big inch engine. My understanding is these CS carbs were the very first TQs. The later production 6000 series carbs that I have seen just have a steel tube in the carb rear for the AV diaphragm, no restrictor, the restriction being a small hole [ larger than 0.015" ] in the diaphragm hose nipple. Seems odd that a performance carb has a device to restrict airflow but production model does not. I have only seen two other TQs that had the brass tube, both 9000 series. One was for an Aussie Ford. There were 5 Aussie models, 9071, 9085, 9091, 9092 & 9333, used on 302-351 engines. The 9333 has the brass tube, others have the steel un-restricted steel tube.

Has anyone done any mods on the brass tube, enlarging the hole? Did performance improve? Any info welcome.
Click to expand...
Haven’t done any mods to mine. Have you run yours?
 
My 2 bits...even the tq with the steel tube have the restrictor..look at it from the other direction.
 
Nope, the steel tube is just that: a piece of plain tube steel with no restriction inside. At least not in the many that I have checked out. The 'restriction' is the small hole in the end of the air valve dashpot nipple.
 
They were ALL Nth American. The ones used here in local Ferds were imported from the USA.
 
yeah if they were aussie made the company name "EMAIL" "Email made under licence from Carter carburetors" or similar would be on there somewhere and their own unique model no. and series, a bit like the fuel pumps.
they did the carter BBS BBD stuff for chrysler australia , fuel pumps some of the alternators and regulators dunno if they supplied ford and holden

funny name who would have guessed it would mean something else years later.
 
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