Damn Thermoquads.

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replicaracer43 said:
And they work there, what's your point?
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It only takes one or 2 comments on Thermoquads to get people riled up lol......

F.A.S.T is just another example of the rules making someone use one. The fact is if they were mainstream and they never were, and never will be that people would have them on everything from A to Z. It's just easier to have a Holley. I could easily offend on this topic so that's my opinion.

Leave no doubt to the naysayers that if the right person knows how to tune them that your car will be unique. I am a huge fan of them and personally will only use a Holley as a last resort for a Street Application and then EFI would happen ASAP.

In June I will be putting my Duster on a Chassis Dyno for a day. With it comes a few intake swaps and Carburetors. My dad is a master with the Thermoquads and with a AFR gauge he will get to work his magic. It's my Father's day gift to him and he will eat it like candy. I bet a Hotdog that TQ will be the best performer of all the Carbs we try....

JW
 
Adding fuel here(pun intended).The twin ring boosters in qj and tq carbs give that crisp response , keeps it lean(economy) and adapts quickly to most driving situations.You are a metering rod change away from a good baseline(don t need to open carb)there is more but not going to go into details BUT then there is that secondary door....Like vacuum advance some disconnect as a reflex, try tuning it out, unless your racing a dominator and you got two throttle positions(idle and wot). Ther actually is some power in there also better economy and will recover quickly from a transition from part throttle cruise to passing(be it part or w.o. throttle)...Getting back to the air door , yes it takes time and patience to iron the bog out but it can be done (engineers that desinged it didn t just decide to invent something that wouldn t work)with very good results . The guys that call the qj the quadrabog usually try to make the door open too fast(they think mechanical secondary), don t treat it like that , you need to have a whole different approach to tune them . I like them on the street but on the track I would go with a holley , I always wondered about combining the two desings together , the sensitive primaries with (tq qj)with mechanical secondary holley???Oh another thing,tq has more fuel bowl than qj (to me that is the biggest shortcomming of the quadrajet)
 
yellow rose said:
Really? Are you sure you've ever been to a drag strip? In Stock and Super Stock they run TQ's. And QJ's.
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Thats because the rules say they have to..given the choice I'm sure anyone running in those classes would have some form of Holley on top of their engines..and yes I'm at the track all the time,next time your there look under the hoods of what guys/gals that are running bracket or point series use I doubt you'll find anyone using a "Thermobog"..
 
never had a problem getting the TQ to run great, and perform even better :) I'll state they may not be as ready "out of the box" as other carbs, but set right they run right every time.
Had a 340 in a '70 dodge truck that got 17 mpg going from Illinois to Colo at 65-70 mph. TQ ran like FI :)
 
RustyRatRod said:
Sorta like why you used a stock intermediate shaft on a high volume pump......Yall really knew your **** back then huh?
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Yes I did just like everyone else does..technical editor:rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl:..pleaseeeeeeeeeeeeeeeeeeeeeeeee...
 
Pulled a cast intake/TQ to install a LD340 intake/750 dp Holley and only dropped a tenth. And that tenth might have been due to the "less weight" off the front end helping the 60' drop a half tenth (street tires). MPH stayed the same, yet many will pay 500 bucks to make this upgrade
 
It has been a couple of days and each time I have gone out to start the car, it fires right up. I can't believe that something as simple as an operational choke made the difference. It has not been cold enough to need a choke...?
The closed choke door opens just a few moments after the engine starts. I can only figure that while it is closed, it forces the accelerator pump to work as opposed to a non functional acc pump with the choke door open during a cold start.
 
Daves69 said:
Referring to the fire video, IMO, there in lies the problem. It's not the carb it's the operator. Evidently priming it with gas (maybe too much), goes to start it, when it fires an explosion happens possibly due to no exhaust on it. Look where the flame originates. I doubt many high school folks had the "know how".
View attachment 1715033542

I do know that these could be a real pain in the ***.................

View attachment 1715033541
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No.
(Tongue in cheek comment to follow)
The whole problem is he has no cooling system installed.:wtf:
 
i never liked the thermoquads.. then i bought my lil red and a friend who is real good with them rebuilt it and tweaked it.. holy **** did that thing run good.. truck still only got 10mpg but damn did it run good.. i have quite a few of them out in the shed.. used to pick them up for 5 or 10 dollars when i saw them.. wish the metering rods and all were more readily available though..

i usually use holleys now.. just a lot easier to get fine tuning parts for them..
 
here is a friends car (physixx). rund a thermoquad.. this is a few years ago.. the car is quite a bit faster today...

 
A 10 sec. run with a TQ, NICE!

I also picked up a bunch of TQ's for there rod and jets. Jets mostly. Bend AFB rods 3/4 of an inch shorter for TQ use. Clip off the rest for fitting.
 
Kern Dog said:
... I can only figure that while it is closed, it forces the accelerator pump to work as opposed to a non functional acc pump with the choke door open during a cold start.
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The choke increases the vacuum in the primaries and that pulls more fuel out of the jets. As for the acc pump not working off the bat, no idea but they not physically linked. TQ may not even need a pump shot to start due to the high vacuum small primary venturis.
as for that holley spreadbore "TQ replacement" carb thats puking fuel everywhere (in a van???) the 390 Holley NASCAR carbs supposedly weep fuel out of alot more places than the boosters...
 
Kern Dog said:
It has been a couple of days and each time I have gone out to start the car, it fires right up. I can't believe that something as simple as an operational choke made the difference. It has not been cold enough to need a choke...?
The closed choke door opens just a few moments after the engine starts. I can only figure that while it is closed, it forces the accelerator pump to work as opposed to a non functional acc pump with the choke door open during a cold start.
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When the choke is closed, engine vacuum is applied to the 4 air bleeds, which then spew raw fuel on top of the throttle blades. Meanwhile engine vacuum is still trying to find air. It pulls extra hard on the low speed circuits, as the fast idle cam has increased the throttle opening. Meanwhile most carbs will engage the vacuum advance on the fast idle. This will provide the needed time in crankshaft degrees,to ignite and burn all that fuel.
As soon as the vacuum breaker sees vacuum, it opens the choke which stops all the spewing. Now you are on the transfers.
This it where it can get ugly. If you the reader, are one of those guys who insists on running 20* or more of idle timing,now the primaries will not be open enough to sustain the engines demand for fuel, and it may die. Typically the cure is increased fast-idle speed. Now the engine is screaming,but getting the fuel it needs; but now way too much air. Typically the cure for that is to close the choke. Which may start the bleeds spewing again, And so it cycles endlessly,
and the carb gets a bad reputation.
When all along the cure was LESS initial timing, and a fully functioning Vcan.
It is for these guys ( not necessarily you Kern), that I preach getting the T-port synced up. The sync will by default, demand the correct idle-timing.It comes out in the wash, no guess-work. When the sync is adhered to, the idle timing will always come in way lower than what one might think, which, with a typical street stall TC matters not one teensey bit. As soon as you step on it, in just a short time,the Rs might climb to 2000 or more where the timing might be 22 or more degrees, and if you are at any normal throttle setting this will combine with the 14 to 22 Vcan degrees for a grand total of perhaps 44*.So for guys running a typical streeter,with huge idle timing, and no Vcans, I'm sorry.
BTW, this message is not for Kern, but rather to future readers of this thread with such a provocative title; I'm sure in the coming years it will receive many hits from the search button.

Congrats Kern on getting yours into the happy zone!
 
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I get a kick out of you thermobog guys if you cant tune a bog out of a thermoquad there is no way you will ever tune any carb. it is the easiest thing to do takes less than 4 minutes .
 
jimjimjimmy said:
I get a kick out of you thermobog guys if you cant tune a bog out of a thermoquad there is no way you will ever tune any carb. it is the easiest thing to do takes less than 4 minutes .
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  • Done it right out of town.... two screw drivers and slowly tightening up the spring tension in the back flap a 1/4 turn at a time :)
I had a hand full of tricks that would help them perform better :D
 
RustyRatRod said:
Just like the stock intermediate shaft had nothing to do with your engine failure. dumbass.
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RustyRatRod said:
Just like the stock intermediate shaft had nothing to do with your engine failure. dumbass.
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No it didn't metal getting into the oil pump and seizing it caused the shaft to snap..Mr Tech editor(that is so fing funny:rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl:..
 
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