Carburetor Recommendations Please
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Senior User
Joined: Nov 2009
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From: TX
Ok. So I got the carb, put it on, and after some adjustments it runs awesome. Much improved over the Eddy. No issues with rpm drops, fuel pressure (it can take the stock 5.5-6psi fuel pump) or fighting hard acceleration above 2000rpm. The response is great and so is the power. Once I get the new gears in the rearend I might be buying new tires shortly after.
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I really like those street demons, Im tempted to buy the 750 version, what i don get is how they get their 750 cfm rating with 1 11/16 " primarys since thats the same size primarys on my eddie 1407?? maybe small venturi size restricting flow? hows throttle response? crisp as advertized?
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From: TX
Best thing I can tell you about the design is to watch the video earlier in this thread.
The throttle response is excellent. I now have to change how I position my foot on the pedal so to feather the gas; otherwise, it's running like a scalded monkey.
The throttle response is excellent. I now have to change how I position my foot on the pedal so to feather the gas; otherwise, it's running like a scalded monkey.
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Joined: Jul 2010
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From: Northeast, OK
Glad to hear that it worked out well. By the way, I asked Tim what he thought of the carb and he said he hadn't really studied it and asked for a link. I sent one to him and yesterday when we talked he said he's going to run one on the engine he's building now when he puts it on the dyno. Should be in about 3 weeks.
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From: TX
Glad to hear that it worked out well. By the way, I asked Tim what he thought of the carb and he said he hadn't really studied it and asked for a link. I sent one to him and yesterday when we talked he said he's going to run one on the engine he's building now when he puts it on the dyno. Should be in about 3 weeks.
I do admit my motor is likely over-cammed and over-carbed now.
Posting Guru
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Yeah i did see the video, i loved old thermoquad carbs aswell as quadrajets, im defenitively buying one.
You can't really over carb with one of those, like tq they will give what your engine needs,besides the 625 version is too small. I have a bigger than usual roller cam on my 408 on a light weight mustang, in 2 months or so i will test one aswell
You can't really over carb with one of those, like tq they will give what your engine needs,besides the 625 version is too small. I have a bigger than usual roller cam on my 408 on a light weight mustang, in 2 months or so i will test one aswell
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From: Northeast, OK
That is the beauty of the Air Valve Secondary, a concept that the TQ and now the Street Demon, share with the AVS/Thunder carbs.
I'm torn between a TQ a guy is offering me and the 750 SD. I, too, love TQ's and QJets and the SD is a chip off the old block with the best parts of several carbs mixed together. And, hopefully, some new engineering thrown in, like the Triple-Stack primaries.
Speaking of the primaries, they say the secondaries provide more than twice the flow of the primaries. At 750 total CFM that would mean the primaries are less than 250 CFM. But, as was pointed out, that the same size as both the primaries and secondaries of the 750 CFM Edelbrock 1407. So, why the reduced flow rate? The Triple-Stack boosters are surely the reason for that.
I'm torn between a TQ a guy is offering me and the 750 SD. I, too, love TQ's and QJets and the SD is a chip off the old block with the best parts of several carbs mixed together. And, hopefully, some new engineering thrown in, like the Triple-Stack primaries.
Speaking of the primaries, they say the secondaries provide more than twice the flow of the primaries. At 750 total CFM that would mean the primaries are less than 250 CFM. But, as was pointed out, that the same size as both the primaries and secondaries of the 750 CFM Edelbrock 1407. So, why the reduced flow rate? The Triple-Stack boosters are surely the reason for that.
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It has to be, venturi size is more important than throttle bore, and im sure a triple stack booster take a lot of space, its all speculation till i get my hands on one..
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From: Northeast, OK
I fully agree on the Venturi size. But many manufacturers don't specify that but do the throttle bore size. So we have to speculate. I think part of the reason they don't specify Venturi size is that it is hard to calculate. The could calculate the effective area, but even that is misleading since the additional surface area of multi-layer boosters reduces the flow beyond what would be indicative from the cross-sectional area alone.
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From: TX
A little update: had to drive the truck 250 miles to attend training (not my choice), and it looks to be getting almost 9 mpg city and 12mpg highway; which is what it was getting when it had a stock cam and 2bbl. Lots of power for passing, even though the kickdown isn't hooked up ( I need an extension, and im away from home so I can't fab something). Overall im happy with it.
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From: Northeast, OK
That says it all. I just didn't look. Sorry. I assume you have the C6 since you mentioned the converter, and still have the 3.00's? And stock heads and compression ratio?
I'm just trying to compare to my to-be build to get an idea of fuel consumption.
I'm just trying to compare to my to-be build to get an idea of fuel consumption.
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What the heck is a hyperneuclectic piston? Never heard of such a thing...