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Re: Are Thermoquads less rich than Holleys
[Re: 68Bullit]
#135867
10/14/08 02:00 AM
10/14/08 02:00 AM
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Joined: Aug 2003
Posts: 4,384
Madison Wi
NTOLERANCE
master
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master
Joined: Aug 2003
Posts: 4,384
Madison Wi
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Before you pull the carb and swap it out, check the opening on the secondary butterflies. On my last 750 holley, I had a similiar problem as you...stinky at idle. Jet changes wouldnt make the smell go away. Friend of mine said it was likely the secondarys (  ) He adjusted them and the engine cleared up alot. Doc
I used to care but....... things have changed
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Re: Are Thermoquads less rich than Holleys
[Re: 68Bullit]
#135869
10/14/08 03:59 AM
10/14/08 03:59 AM
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Joined: Jul 2008
Posts: 30,538
Florida STAYcation
dOc !
The village idiot's idiot
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The village idiot's idiot
Joined: Jul 2008
Posts: 30,538
Florida STAYcation
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Quote:
Just as a general rule, are they less rich? I've always heard that Holley performance carbs are inherently more rich than other carburetors. I'm looking for something that might be a little more easy on the eyes  in the carport during startups. Also, my Holley is a 750dp, so would the TQ be better in the way of gas mileage?....Thanks
As a general rule .... the TQ does a muchO better job mixing the air and fuel....specificly on the primary side. With this considered and with the same efficency ignition system on both carbed systems .... the TQ supplied mixture will light-off better and more completely than a typical Holley. THUS .... the appearance that people think that they are "richer".
And a MPG run-off between a DP Holley and a TQ ? ... the Holley will be "buried" !! Now under WOT ...it is a diff story.
But some people are working on making the TQ muchO bester under WOT.
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Re: Are Thermoquads less rich than Holleys
[Re: 62maxwgn]
#135872
10/14/08 10:27 AM
10/14/08 10:27 AM
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Joined: Apr 2007
Posts: 2,926
Calgary, Alberta Canada
a12rag
master
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master
Joined: Apr 2007
Posts: 2,926
Calgary, Alberta Canada
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Any carb could be rich . . .depending on how it is tuned and the application.
I have always had great experience with TQs. Anytime I have rebuilt mine, it has been back to the factory specs. And, as was mentioned, all adjustments done in order ! Great starting, throttle response and mileage ! 23mpg in 74 Duster360 @ 55-60mph. Solid 20mpg @ 70mph . . . course I think the 2.45:1 rear end helps too !
I think if you have bad experience with anything, you will knock it . . . lots of guys out there swear by Holley, lots swear AT Holley carbs ! Same goes for the TQ. . . . best bet is to find someone that understands your Holley, and has the tools to adjust/tune it correctly. No need to swap carbs if everything is working right !
Cheers
Mark
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Re: Are Thermoquads less rich than Holleys
[Re: a12rag]
#135873
10/14/08 10:15 PM
10/14/08 10:15 PM
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Joined: Jul 2003
Posts: 6,167
Maryland
GO_Fish
master
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master
Joined: Jul 2003
Posts: 6,167
Maryland
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TQ's were emissions carbs (same for AVS)that had to pass EPA testing of the day, where the Holley DP's were not intended for use on stock engines. So with both in stock form, the TQ would be leaner.
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
69 340 GTS stock 14.18@ 95.60 mph
01 5.9L Ram 1500 Quad Cab 4x4
01 3.5L 300M 16.23@ 86.97 mph
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Re: Are Thermoquads less rich than Holleys
[Re: 68Bullit]
#135874
10/14/08 10:33 PM
10/14/08 10:33 PM
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Joined: Jan 2003
Posts: 6,816
Alton, IL
Dakota_Don
master
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master
Joined: Jan 2003
Posts: 6,816
Alton, IL
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Quote:
Just as a general rule, are they less rich? I've always heard that Holley performance carbs are inherently more rich than other carburetors. I'm looking for something that might be a little more easy on the eyes in the carport during startups. Also, my Holley is a 750dp, so would the TQ be better in the way of gas mileage?....Thanks
would this be on cold start up with the choke on??
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Re: Are Thermoquads less rich than Holleys
[Re: Dakota_Don]
#135876
10/15/08 01:29 AM
10/15/08 01:29 AM
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Joined: Mar 2008
Posts: 571
Western NC
68Bullit
OP
mopar
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OP
mopar
Joined: Mar 2008
Posts: 571
Western NC
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Quote:
would this be on cold start up with the choke on??
No choke on this 750. And yes it does it on cold start-up, but it also does it when it's completely warm (180+ temps) and at idle. Not smelling anything going down the road but only while idling. It's pretty bad. Odor get's into my clothes too Oh, and I just drove the car earlier in this evening and the fuel economy seems to be way less than it should be even for a double pumper.
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Re: Are Thermoquads less rich than Holleys
[Re: NTOLERANCE]
#135877
10/15/08 01:34 AM
10/15/08 01:34 AM
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Joined: Mar 2008
Posts: 571
Western NC
68Bullit
OP
mopar
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OP
mopar
Joined: Mar 2008
Posts: 571
Western NC
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Quote:
Before you pull the carb and swap it out, check the opening on the secondary butterflies.
On my last 750 holley, I had a similiar problem as you...stinky at idle. Jet changes wouldnt make the smell go away. Friend of mine said it was likely the secondarys ( ) He adjusted them and the engine cleared up alot.
Doc
Thanks Doc. How do I check the secondaries? Do I check them while the engine is at idle? And what exactly am I looking for when I check?
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Re: Are Thermoquads less rich than Holleys
[Re: 68Bullit]
#135878
10/15/08 07:38 AM
10/15/08 07:38 AM
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Joined: Jul 2007
Posts: 531
Virginia
JimG
mopar
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mopar
Joined: Jul 2007
Posts: 531
Virginia
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Bullit:
One very common problem with Holleys - a problem that produces exactly the rich idle you're experiencing - is that you've possibly got the curb idle screw cranked too far open to get the desired idle speed. Too much of the transfer slot might be exposed, causing the mains to operate at idle.
Take the carb off and look at the underside. On the primary side below each throttle plate, you'll see a small hole. That's the idle discharge port. Above that (you may have to crack the throttle open to see it) is the idle transfer slot. It's a rectangular slot, probably .180 - .250" long. When the throttle plates are closed against the curb idle screw, you should only see enough of the transfer slot that it looks like a square.
This is commonly a problem on larger CID engines.
Assuming you don't have something else you to need fix that is causing you to need to crank the curb idle screw open, there are 2 common fixes, each with advantages and disadvantages: you can open the secondary idle stop a bit more (assuming you don't open it so far that you create the same problem on the secondaries that you've got on the primaries) or you can drill small holes in the throttle plates.
If you're like most people with this problem, I'll bet you've got too much transfer slot expesed - check it and report back.
I'm assuming the float levels are OK?
Jim
Last edited by JimG; 10/15/08 07:49 AM.
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Re: Are Thermoquads less rich than Holleys
[Re: bacaruda]
#135879
10/15/08 08:46 AM
10/15/08 08:46 AM
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Joined: Jan 2003
Posts: 9,436
Blair County,PA
62maxwgn
master
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master
Joined: Jan 2003
Posts: 9,436
Blair County,PA
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Quote:
I'd like to see the 11 step program, but I've adapted an electric choke to an 800. Works ok. I think fuel pressure can also vary the calibration.
Can too much PSI actually bend a float arm?
If you can find one of these little gems it will give you everything.Actually,there are twelve adjustments to be made in order.You won't find that information in the typical tune up kit.Only other source is FSM.
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