WHO KNOWS CARB TECH UPDATE

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WAYNE0

WAYNE0

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Ibought a new quick fuel blo-thru carb. Its running rich. I dont know much about carb techs. With a friends help i changed the jets 3 numbers lower. It still runs alittle rich. You cant smell it like you did. It also smokes alittle at idle and more so when you run the RPMs up.Also notice a small oli leak around the oil filter.
 
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It sounds like you are headed in the right direction with the jetting. Have you looked for a manual or any other info online for this carb?
 
coloradohill said:
It sounds like you are headed in the right direction with the jetting. Have you looked for a manual or any other info online for this carb?
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Ihavent been able to find any yet. Not sure how low i can go on the jets. I dont want to go to low since they say fuel is a big thing on higher RPMs for a super charger.
 
Here is a paragraph from this manual.

Quick Fuel carburetors have been calibrated to operate on a broad cross-section of engine combinations. While it is not possible for a single calibration to work virtually every conceivable application it should work on most engines and it willnot be necessary to make any additional adjustments and/or tuning. Should it be necessary to alter the fuel curve in ourHot Rod Series there is plenty of tuning capability available with changeable air bleeds, power valve channel restrictions,and idle feed restrictions.

manual,
https://documents.holley.com/199r11667.pdf
 
You didn't give us much information, so it's hard to guess. However, I can tell you what happened to me. About 12 years ago, I put a 750 CFM Edelbrock carb on my mildly modified 340 (about 375HP). I went from a 600 CFM that likely needed to be rebuilt. It ran GREAT. Acceleration and tire burning were great. But every time I drove it, you could smell gasoline. I dropped the primary jets down by 2 sizes, and it made a huge difference. There was no more raw gas smell when I cruised around, and I still had the power. It sounds like you are on the right path. You should consider installing new plugs. If you were running rich for very long, the plugs might be pretty sooty/fouled. You could, perhaps, clean them, but plugs are cheap.
 
@WAYNE0 my best advice to you is stop messing with your carburetor and go put the car on a chassis dyno and pay someone to tune it. You need a fairly thorough understanding of all of the circuits in a carb to be able to tune a blow through set up. And swapping jets ain’t it.
 
TT5.9mag said:
@WAYNE0 my best advice to you is stop messing with your carburetor and go put the car on a chassis dyno and pay someone to tune it. You need a fairly thorough understanding of all of the circuits in a carb to be able to tune a blow through set up. And swapping jets ain’t it.
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Absolutely, the best way to go, even for ones that do know about carb tuning.

AND the smoke may just be solved with more PCV since it’s getting blown into.
 
TT5.9mag said:
@WAYNE0 my best advice to you is stop messing with your carburetor and go put the car on a chassis dyno and pay someone to tune it. You need a fairly thorough understanding of all of the circuits in a carb to be able to tune a blow through set up. And swapping jets ain’t it.
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I was going to say get a wideband O2 setup to get an idea of what the AFRs actually are but I think with the OP's experience level I have to agree, getting a dyno tune first is the safest and best option.
 
Sounds like there’s more to the story.

FUEL SYSTEM/ SC HELP

If I read that correctly he’s using a fuel injection style in tank pump with a non return style carbureted regulator. I think we need clarification.
 
TrailBeast said:
Absolutely, the best way to go, even for ones that do know about carb tuning.

AND the smoke may just be solved with more PCV since it’s getting blown into.
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In this thread there are pictures that show a pcv still plumbed in. That needs to go asap and a catch can installed.

CARB HAT TO SC
 
ok here is what i have 360 397 ci 8.8 compression 750 cfm quick fuel blo-thru carb paxton super charger 7-8 pounds of boost msd btm ignition box wl vaccum port that goes to intake holley 350lph in tank fuel pump (this what holley recomended) holley fuel regulator w/ return line going to tank ( this also what holley recomended) champion 11yc spark plugs paxton recomened 1-2 colder plug also the fuel regulator has a vaccum port that goes to the carb hat I was told not to change the jets because it would make it to lean at higher RPMs Cant think of anything else The pics are before the correct fuel regulator, carb hat

SUPERCHARGER PICS 5 5 24 001.JPG


SUPERCHARGER PICS 5 5 24 002.JPG


SUPERCHARGER PICS 5 5 24 003.JPG


SUPERCHARGER PICS 5 5 24 004.JPG


SUPERCHARGER PICS 5 5 24 005.JPG


SUPERCHARGER PICS 5 5 24 006.JPG
 
WAYNE0 said:
Ibought a new quick fuel blo-thru carb. Its running rich. I dont know much about carb techs. With a friends help i changed the jets 3 numbers lower. It still runs alittle rich. You cant smell it like you did. It also smokes alittle at idle and more so when you run the RPMs up.
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What color smoke ?
 
Changing jets will do nothing to affect the rich condition at idle. That’s all on the idle feed restrictors and idle air bleeds in combination with the needles and where on the transfer slot you are. Like I said, spend good money and go get it chassis dyno tuned, by a good carb tuner.
 
And you need to get rid of the pcv valve and block that port on the bottom of the carb as you are pressurizing the crankcase. Those pcv valves don’t seal well with positive pressure on them (In fact most don’t). Install breathers in both valve covers at a minimum.
 
TT5.9mag said:
And you need to get rid of the pcv valve and block that port on the bottom of the carb as you are pressurizing the crankcase. Those pcv valves don’t seal well with positive pressure on them (In fact most don’t). Install breathers in both valve covers at a minimum.
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iit doesnt have a pcv valve Iwas told to get ride of it The carb has no vaccum ports
 
TT5.9mag said:
Changing jets will do nothing to affect the rich condition at idle. That’s all on the idle feed restrictors and idle air bleeds in combination with the needles and where on the transfer slot you are. Like I said, spend good money and go get it chassis dyno tuned, by a good carb tuner.
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Sounds like a plan As soon as i find one
 
Took it for a test drive today. It runs good and has good pull. I didnt look in the rear view mirrior to see if was smoking because i was to busy driving. It needs an front end alignment. When got back i shut it off then started it back to see how the timing was since it was up to temp. I was then i noticed a very small amount of black smoke out the exhaust but it goes away when i rev it up. Ill look at the plugs to see how they are.
 
When convenient, weld an O2 bung in the exhaust. A wideband can be after the collector, even a temp insert up the tailpipe. A regular O2 sensor needs to be close, where still hot, so one in each bank. Wideband kits are now affordable. Otherwise, you are "flying blind". Old guys rely on looking at the tailpipe or viewing spark plug color, but not as quantitative. Also need a pressure gage at the carburetor feed. If >5 psig, the pressure might be forcing the float needle open and flooding the carburetor.
 
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