Freiburger Explains Thermoquad Carburetors! - Roadkill Extra

The cry of “Thermoquad!” became famous in Roadkill episode 23, the one where the guys build the General Mayhem ’68 Dodge Charger using a 440 engine from a motorhome. Freiburger announced the Thermoquad as the only carburetor that punishes you for going to wide-open throttle. But what is a Thermoquad, really? Watch this Roadkill Extra and you’ll find out.

[mustie]

and dont forget to flip the stock air cleaner lid over for even more sound,

[weansardman]

I love the sound of a quadrajet when the secondaries open up.

[richardturk]

Had one on my 71 Dodge Demon and it always seemed to starve the engine when you stood on the throttle. I was running NHRA stock class so I got in touch with Ed Hamburger at MOPAR and he showed me how to modify the accelerator pump lever and how to get the air valve on the secondary to open all the way.
Once I got that sorted out that 340 screamed at wide open throttle.
I liked that carb because I never had a fuel percolating problem at the track on a hot day and no vapor locking.

[secondcamarostreetmachin]

Freiberger, around 1972-73, I ran a 1000 cfm thermoquad on a 283 SBC with an adapter on a Z28 manifold and Z28 solid lifter cam with a 4 speed behind it in a little Chevy II. Worked perfectly. No complaints here.

[richardturk]

My 71 340 dodge demon had one and my MOPAR direct connection dealer had all the good tech info to make them work fantastically.

[JohnnyizAlive]

Such an old video but I have to comment.

The thermoquad came in three different CFM ratings. If you're lucky enough to have a first run issue on a 340 that was the 1000cfm Competition Series.
The 800-850 was next and it's secondaries are 1 1/2 with the third being the 800s whose secondaries are the smaller 1 3/8.

The secondaries are considered vacuum and not mechanical. It must be used on a spreadbore intake and as someone else mentioned WITH the 1/2 spacer as it also displaces heat. Not using the spacer, and placing the TQ directly on the intake, is the primary reason for the phenolic bowl to warp. The other reasons that can cause issues are using a screwdriver to pry the air airhorn off or over tightening of the airhorn's 10 bolts.

The main reason why people do NOT like the TQ and may prefer Holley is that they don't take the time to properly adjust the TQ, but when properly adjust will outperform equivalent carburetors of the competitor's if done right.

People prefer Holleys and Edeljunk as they are easy to work on but who wants to keep replacing power valves and adjusting float levels at every turn on a Holley or adjusting the A/F on an Edeljunk day in and day out?

Take the time to do it right and the TQ will smoke the competition. I have ran a TQ for three years after trying numerous Holley and Eddy carbs and the others are just a time consuming hassle. If you set the TQ properly, you wont have to touch it for a very long time.

[pepitomateo]

Thermo-Quads are not easy to tune but they are great, great carburetors! Smooth idle and smooth ride in low rpms, great torque and incredible top end power! I’ve tried almost everything in my bbc, Holley, Edelbrock, fitech, I really like the Thermo-Quad better, awesome Carburetor!!

[craigcontofalsky]

David, I been rebuilding Thermo Quads since 1971! Great carb! I have the 750 cfm on my 71 Demon 340
I also have a 1, 000 cfm my buddy ran in 1972. Easy to rebuild. My last rebuild was 1985 and still running strong! Love the sound too!❤

[stevenshepherd]

Nothing was as cool as the sound you got from flipping the lid on one of these.

[seniorjohnl]

The AFB worked the same way, the secondaries were mechanical but it had the air vane above that only opened if air demand was there. Supposedly you could tune the air vain by adjusting the spring, but I never got that far.

[poormanrc]

For a carburated off roader you cant beat a tq, those sidemount floats keep fuel going while on an incline.

[LKRS]

Quadrajet carburators are great, plus the sound of them at wide open are even better.

[RobertKohut]

I can remember going to the scrap yard and finding one of these on a Dodge and taking it. Loved the "Thermal Quad" idea!! LOL I stuck it on a 318 that I put a 4 barrel intake on. It ran okay and made a great noise...LOL..LOL

[davidcollis]

I have rebuilt many Thermoquads. They are good carburetors. Usually, all that was wrong was the 2 thick rubber washers for the main wells would get soft or crack.

[felixdzerjinsky]

74 Plymouth Satellite police package....high performance 360 with the Thermoquad. Secondaries were like toilet bowls. Loved the sound when you put it to the floor.

[jordanwiley]

Quadrajets and Thermoquads are great carburetors. People only dislike them because they're too dumb to know how they work. Or they rather have the easy carburetors like holleys or edelbrocks. which is understandable. In a hurry on race day, pop the front bowl off your holley, change jets, off ya go. Qjets are set and forget, but they look scary and daunting to the uninformed and are not very user friendly. They only bog if the air doors are too loose. That's it. On qjets there is a little 3/32 allen set screw and a flathead screw. Adjust the tension, drive around, floor it, repeat until bog is gone and carb performs to your liking. Not hard.

Also, for you new or old to the world of Qjets, if you have the later hot air/electric choke style (usually '75 and up had em), take the carb apart, punch out that aluminum plug infront of the choke tower, and tap it for a pipe plug. Badda bing badda boom. Instant adjustable part throttle without having to take the damn airhorn off. An AFR gauge helps wonders too. I've seen people get an additional 5mpg from tuning the apt screw alone.

[simplyfred]

The one on my 340 Cuda ripped very well. The 4 spd was a riot.

[kyletaff]

Freiburger is the only person that can say thermoquad in the way it sounds like it should be said

[greensparks]

that was good and straight to the point thanks keep up the good work guy's

[CircuitStudiosMO]

you can adjust the spring tension for the secondary and there were different needles and you can adjust the needle heights very customizable