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Old 02-18-2004, 04:55 PM
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holley carb... vaccume secondary to mechanical?

basically what i want to know is can i just put the mechanical linkage on my vaccume secondary carb? it's either that or have tuning problems like crazy... it's on my turbocharged v8s10, and i don't realy want to butchure the carb to bad to make the vaccume secondaries open under boost... the bad part about it is once the secondaries are set up to only open under boost then there is no way of making them open out of boost... hence why i want mechanical secondaries any idea's?

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Old 02-18-2004, 05:11 PM
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yes you can make your vacuum secondary`s open on demand, but it will result in a bog since there is no secondary fuel shot as there is on a mechanical secondary carb, this is why mechanical secondary carbs are also called double pumpers.
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Old 02-18-2004, 05:22 PM
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You cannot convert a vac to a mechanical. Meaning turn a 3310 into a 4150. If you want/need a mechanical carb you will be money ahead to just buy one. I tried to convert/rig one before (years ago) and as mentioned above I could not cover up the "hole" when the secondaries opend and that resulted in an embarassing bog/backfire/stumble/stall whenever I nailed it.

There is no secondary pump shot on vacuum secondary carbs, this means you get a very lean condition when the secondaries are forced open.

Royce
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Old 02-18-2004, 06:50 PM
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Quote:
Originally posted by camaroman7d
You cannot convert a vac to a mechanical. Meaning turn a 3310 into a 4150. If you want/need a mechanical carb you will be money ahead to just buy one. I tried to convert/rig one before (years ago) and as mentioned above I could not cover up the "hole" when the secondaries opend and that resulted in an embarassing bog/backfire/stumble/stall whenever I nailed it.

There is no secondary pump shot on vacuum secondary carbs, this means you get a very lean condition when the secondaries are forced open.

Royce
4150 means two metering blocks. An original 3310-1 is a vacuum secondary 4150. A have a few vac. sec. 4150s.

There is no way that works to convert them to mechanical actuation. There is a gear drive kit to convert to mechanical secondaries, but it is a big joke.

Buy a mechanical secondary carb. They aren't too expensive on Ebay.
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Old 02-18-2004, 07:04 PM
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lluciano77, you are correct I should have added double pumper to my 4150 statement.

Royce
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Old 02-18-2004, 07:39 PM
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Vacuum Secondary to Mechanical Secondary

On some of the older vacuum secondary carburetor the bodies where the same between them and the mechanical secondary carburetors. By the time you changed all of the linkage, and machine the main body, and metering circuitry you would be money ahead selling what you have, and putting the money towards a mechanical secondary carburetor.
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Old 02-18-2004, 07:47 PM
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How do you machine for the secondary squirter check valves? I thought that was Holleys own tooling, not something you could buy.
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Old 02-18-2004, 09:21 PM
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Quote:
Originally posted by DoubleVision
yes you can make your vacuum secondary`s open on demand, but it will result in a bog since there is no secondary fuel shot as there is on a mechanical secondary carb, this is why mechanical secondary carbs are also called double pumpers.

i think the way i would do it would work fine... i would need to make it open under boost only... it shouldn't be too bad of a bog because of the fact that it will be making boost, however this could be kind of a scary thing also because of detonation problems... i think i'm gunna try and make it work though... thanks for everyones help
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Old 02-19-2004, 06:52 AM
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Without the additional fuel from a secondary accelerator pump you're most likely not going to get the secondary boosters to start quick enough to not have a hesitation.
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