Does VV = CFI?
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Does VV = CFI?
I've seen CFI listed in some FI manuals as being Frod's first attempt at FI. Is this the same thing as what is commonly called VV or Variable Venturi?
Feel free to express opinions on them AFTER you answer my question.
Thanks,
Feel free to express opinions on them AFTER you answer my question.
Thanks,
Post Fiend
Joined: Feb 2001
Posts: 6,328
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From: Iowa
Does VV = CFI?
Ferguson
No they are not the same. VV is some engineers warped idea of a carburetor. To say they were not much fun to try to make work correctly would be a gross understatement.
'fenders
No they are not the same. VV is some engineers warped idea of a carburetor. To say they were not much fun to try to make work correctly would be a gross understatement.
'fenders
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Joined: Jan 2002
Posts: 4,907
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From: suburban atlanta
Does VV = CFI?
'Fenders got that right. CFI is the first go at fuel injection. It is, I believe, shorthand for Centralized Fuel Injection, where there is one or two injectors placed atop an "air horn", basically a carb base with throttle plates, but no jets or venturi of any sort. One injector for 4/6 cyl, 2 for the 8's with separate intake runners.
The VV was a 'variable venturi' carb that had two 'plastic' blocks that were moved by engine vacuum, back and forth to open & close the venturi formed between them and the carb body. They each had a tapered needle that adjusted the fuel mixture as they moved back and forth. Kind of a super SU. The British made the SU for MG, Jag, Austin-Healey and others where a piston was sucked up by vacuum, opening the venturi and also allowing more fuel to flow as the tapered needle moved out of the jet. They worked much better for some reason... Maybe it had something to do with the oil leaking on the garage floor making the vapors that lubricated the pistons.. who knows.
More than you ever wanted to know...
tom
The VV was a 'variable venturi' carb that had two 'plastic' blocks that were moved by engine vacuum, back and forth to open & close the venturi formed between them and the carb body. They each had a tapered needle that adjusted the fuel mixture as they moved back and forth. Kind of a super SU. The British made the SU for MG, Jag, Austin-Healey and others where a piston was sucked up by vacuum, opening the venturi and also allowing more fuel to flow as the tapered needle moved out of the jet. They worked much better for some reason... Maybe it had something to do with the oil leaking on the garage floor making the vapors that lubricated the pistons.. who knows.
More than you ever wanted to know...
tom
Post Fiend
Joined: Feb 2000
Posts: 5,130
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From: Brea CA
Does VV = CFI?
>Feel free to express opinions on them AFTER you answer my
>question.
I think you got your question answered so....
Let me tell you how much a POS that VV "thing" is. I don't know how many hours I wasted tinkering, trying to get it to run right, it just won't. They are complicated and expensive to rebuild too. Also, when they first came out, a lot of 'em caught fire! Slapping on a good 'ol Holley 2V made a world of difference on my '79.
Sorry for the rant, you just touched a sore spot!
Barry
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Does VV = CFI?
Thanks guys,
Now I know what they both are and that the VV is a POS per someone's first hand experience. That's exactly the type of info I wanted - a brief explanation of what they are and whether they're any good.
Thanks,
Now I know what they both are and that the VV is a POS per someone's first hand experience. That's exactly the type of info I wanted - a brief explanation of what they are and whether they're any good.
Thanks,
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