Ford Forums banner

1 - 20 of 22 Posts

·
in his big ZH
Joined
·
131 Posts
Discussion Starter #1
Does anyone know what cfm the carter thermoquad is rated too? I hear that there is things you can do to it to really get it cranking.
 

·
'60 F100 Q-Code
Joined
·
750 Posts
Big_Matt said:
Does anyone know what cfm the carter thermoquad is rated too? I hear that there is things you can do to it to really get it cranking.
Big_Matt,

You need to identify the model of carburetor you have. The Thermoquads can be identified by taking a look at the number stamped into their base plates on the left rear corner of the carburetor. See:



...for a better idea of what I'm talking about.


You probably have a 600 if it is on a Cleveland--if my memory serves me correctly--but my Carter book (now hopelessly lost) seems to me that it had about a million different part numbers and CFM variations for the Thermoquads, so I can't tell you. However, once you get your number, you can ask someone who still has their books like the guys at Carbtech.com. You can ring them up and ask them if you can't easily find someone locally. Alternatively, you can post it here and one of us in the US will do it to save you the long distance rates. Or you can call them yourself at: (714) 990-1484 The number is in SoCal US.


:davis:
 

·
Registered
Joined
·
1,067 Posts
Big_Matt said:
Does anyone know what cfm the carter thermoquad is rated too? I hear that there is things you can do to it to really get it cranking.
They are a nice carby, but you can't readily get hold of new springs, jets and metering rods. This makes them very difficult to tune. If you have a relatively stock motor this isn't such an issue.
 

·
Proudly Average
Joined
·
1,305 Posts
i can't find anyone in Brisbane who will even set the bloody idle on my thermoquad... it's got a massive flat spot that i reckon has something to do with the opening of air doors and/or the primary/secondary changeover while i'm on the throttle (like my amatuer descriptions??), but every "carburettor specialist" i phone says "it's got a WHAT?? piss that off and chuck on a 600 holley..."

and now on topic, i read somewhere that they can flow up to 650cfm... but that might've been the version used on Val's... there's a really good website on them, a link to it was posted in one of the other thermoquad threads...
 

·
in his big ZH
Joined
·
131 Posts
Discussion Starter #5
An uncle of mine said he had one go to 980. Now he might be getting old and cant remember that it was 680, or he might have been doing some serious fiddling, also a possibility.

At the moment my running ZH has a 600 Holley, the ZH that hopefully will be running for the first time since Dec 5 in about 1/2 hour, will be running a carter thermoquad. (the one about to run is the white one in my avatar).

Trouble with the 600 Holley I have is that its a square bore so it goes through a bit of petrol in standard driving, not to mention its tuned to rich and the kickdown cable wont let me get into 3rd until about 105 km/hr. Since the carter has a spread bore and bolts on easily, i was thinking of putting it back on my currently running ZH.
 

·
74 XB Fairmont
Joined
·
5,113 Posts
The size or type of the carb has nothing to do with your fuel economy. The weight of your car/the diff ratio and your right foot affect your economy in a big way.

To get better economy you have to make your engine more efficient with the fuel it burns. Develope a few more hp and you'll get more k's to the tank.

Like I keep saying my mates XB coupe runs a 650 double pumper. It's virtually stock apart from;

Cam
Carb
Springs
Exhaust (still runs manifolds)
3.5 open rearend

It develops 163rwkw and it does 440-450k's per tank. Most standard Clevo's struggle to go past 200-300k's per tank I've found. my stock one got nothing over 220k's per tank. Modified that same car gets 350-380k's per tank. It's more efficient even though it rana 3500rpm histall and a 4.11 rearend.

Everyone assumes a 2.77 or 2.92 diff is great but they fail to realise their wasting the fuel on take off. It'd be more efficient with a 3.23 or 3.5.

Brenden
 

·
Registered
Joined
·
1,927 Posts
Thermoquads have a reputation for set-and-forget reliability. Also it is the only carburettor that will get your ZH through a full NSW blue slip inspection as it is the correct carb to comply ADR27a.
(Most!)Holleys are a dumb design because of the gaskets below fuel level, eg front and rear bowls and accelerator pumps. Thats generally why your car catches fire cause they LEAK!
If your thermoquad (or any carb) has a flat spot it is probably because your accelerator pump is not working. Thermoqauds are notorious for this.
 

·
in his big ZH
Joined
·
131 Posts
Discussion Starter #10
The layout of a carby does effect the fuel ecconomy noticably, ie square bore and spread bore. My holly is a square bore so it goes through a little more for std cruising
 

·
'60 F100 Q-Code
Joined
·
750 Posts
STROKEXD said:
I actually thought that the thermoquads were 850cfm or more for all models. But you can't compare an 850 CT to an 850 Holley...
The TQs range from 500-1000 CFM with many points in between. Nearly all TQs installed on Fords were of the 600-680 CFM category. I've seen a 500 and a 550 installed on different engines years ago, but was not sure of their originality. The Themoquad was commonplace on dual carb applications during the late 50s to mid-60s when Holleys really started replacing them on nearly every application.

I don't have my book (or just can't find it) anymore, but my recollection was something along the lines of:

500
530
550
575
600
625
650
680
700
715
730
750
760
770
780
800
810
830
850
880
900
950
1000

...but I am probably missing several and/or just plain wrong on a few of them. I believe that there were a few more x25, x70 values and x75 values, but I remember them any more. I thought that there were also a number of values in the mid-to-high 4xxs. I was really more of an AFB guy than a TQ guy when it came to dual quad cars where you couldn't run Holleys.

I guess that the bottom line is that we really need a true TQ guy to dispell the BS!

:davis:
 

·
'60 F100 Q-Code
Joined
·
750 Posts
Big_Matt said:
The layout of a carby does effect the fuel ecconomy noticably, ie square bore and spread bore. My holly is a square bore so it goes through a little more for std cruising

Most spreadbore carburetors are more fuel efficient all the way around. This is because the very small primaries act more like a 2bbl carb for most average driving when the secondaries are never called to act. The very large secondaries can "make up for" the relatively tiny primaries when all four are wanted such that total CFM available is equal or even larger than a similar squarebore carb.

Also, most spreadbore factory-installed carbs tend to have vacuum secondaries, which only open (when properly tuned and maintained) when demand requires it. Compared to a squarebore Holley DP, they are much more efficient for typical crusing/driving. They tend to be only marginally better fuel economizers when compared to a VS Holley of similar capacity.

:davis:
 

·
Registered
Joined
·
1,927 Posts
Ah yes, there's nothing quite like the sound of a thermoquad at full throttle!
 

·
HOG Member!!
Joined
·
52 Posts
i remember when my XC ute was stock many years ago and i had trouble with the quadrajet so replaced it with a Holley 6oo dp (square bore). it was a shocker with next to no low down torque. i soon found another quadrajet carb for it.
 

·
Registered
Joined
·
1,373 Posts
davis said:
The TQs range from 500-1000 CFM with many points in between. Nearly all TQs installed on Fords were of the 600-680 CFM category. I've seen a 500 and a 550 installed on different engines years ago, but was not sure of their originality. The Themoquad was commonplace on dual carb applications during the late 50s to mid-60s when Holleys really started replacing them on nearly every application.

I don't have my book (or just can't find it) anymore, but my recollection was something along the lines of:

500
530
550
575
600
625
650
680
700
715
730
750
760
770
780
800
810
830
850
880
900
950
1000

...but I am probably missing several and/or just plain wrong on a few of them. I believe that there were a few more x25, x70 values and x75 values, but I remember them any more. I thought that there were also a number of values in the mid-to-high 4xxs. I was really more of an AFB guy than a TQ guy when it came to dual quad cars where you couldn't run Holleys.

I guess that the bottom line is that we really need a true TQ guy to dispell the BS!

:davis:
Davis

Before my last post I looked up my user manual to check the cfm of the TQ that was spec'd on the 351 in my car (79 Aussie 'Black' block, 2V heads, 4v plenum) but it wasn't specified.

But I do recall reading a performance test over the years that the cfm for this model was 850. Part # is TQ-9142S, would be curious to know what it was.
 

·
Registered
Joined
·
1 Posts
Hello all!

I should apologize for jumping in on this thread first of all.

Secondly,I'll introduce myself.My name is Paul,and I live in Canada.Im foremost a Mopar guy,but have owned several Fords.My fisrt car was a 1970 Mercury cougar XR7 with a 351 Windsor.Second was a 1988 Ford Mustang with a 5.0 litre H.O and 5 speed transmission.

I have had less distinguished fords as well,but those are the two of note.

Third,my reason for posting.As a Mopar fan,I see a lot of thermoquads.I have around 5-6 sitting on my shelf in my workshop,all around 800-850 cfm.

Thermoquads came on just about every Mopar ever built,on almost every engine.The police interceptor version of the 318 came with 360 large port heads and an 800 cfm thermoquad.There is one residing in my current vehicle,a 1983 Plymouth Caravelle( Canadian version of the Fury).

Thermoquads came on the legendary 340,the hi performance 360,the big block 400 C.I and 440.Mopars are a wealth of thermoquad parts!

Anyways,I digress.

My reason for posting is this;

Im a little envious of you aussie ford guys as it appears you got the better version for a choke system.I saw a picture of a thermoquad with an electric choke on the net!This choke appears to reside in it's own circular housing on the side of the carb,much like a rochester here has.

I'd very much like to see pictures in detail of this setup.I would also love to convert my current thermoquad to this setup and am hoping (with your help) I can fabricate something.I would need the necessary linkage,housing,bimetal spring,etc..

The stove type choke is all North American thermoquads ever got.It's a troublesome setup.This is my reason for wanting to do this.That,and I currently have no choke!
 

·
Registered
Joined
·
337 Posts
I thought that every thermoquad fitted to an Aussie clevo was the same and 780CFM. Thats why they make such a huge induction roar under full throttle. Because there a bloody huge carb, especially on a 302.

I just ditched the 650 and 600 holleys that I was playing with on my clevo and fitted a new 600 Edelbrock AFB, its a completely different car to drive now. More bottom end, more top end, smoother transitions through out your throttle position. And All i did was bolt it on and go. I will have it set up on the dyno when I fit the new engine but for this old slug its made a huge improvement.
 

·
Registered
Joined
·
475 Posts
Funny really, I always thought Thermoquads were only available in 2 sizes, 800 and 1000. Sure, Carter make heaps of different sizes, and therefore you can get all different size "Carters", but TQs had only 2 different sizes, with Ford Aus using the 800 cfm version. But, maybe I am mistaken......

Seems to be a bit of a market for them on ebay now. I used to have them given to me, although sometimes I used to pay for them (no more than $10....). Might be time to check the shed soon and see what's left. I know I have a nice little home made "tuning kit" which has quite a few different size needle sets, springs, jets, etc.

On a side note, the "power enrichment circuit", which is made up of the stepped needles and spring/piston can be made to be adjustable. So you don't have to keep swapping/shimming springs to get the timing right (fuel timing, not ignition timing). But, then again, I wonder who else goes to that trouble????
 

·
Richard
Joined
·
1 Posts
Look up demonsizzler? on the net he knows all about tq's. They are all from 800 to 1000 cfm and are about the easiest carb to work with. I have had them on every thing from a stock 302 to a built 454 FE. I usually just fix whatever is wrong with them at the time, rejet and forget about them. They are that good. I can have a killer carb for about 15 to 30 dollars instead of 400 to 1000 dollars for a holley. They are so simple to figure out and fix if you just pay close attention to what you are doing. Also they keep the gas cooler by at least 20f degrees.
 
1 - 20 of 22 Posts
Top