Vacuum leak add power

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RCJ
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Vacuum leak add power

Post by RCJ » Fri Jun 15, 2018 8:47 am

If you have a restricted carb because of rules can you use a vacuum leak to add some power?

Brian P
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Re: Vacuum leak add power

Post by Brian P » Fri Jun 15, 2018 9:03 am

I know it's been done ...

It depends whether the organizers wise up to it and write the rule in a way that prohibits it and which they can enforce.

DrillDawg
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Re: Vacuum leak add power

Post by DrillDawg » Fri Jun 15, 2018 9:12 am

What is the restriction, carb size or plate.
BORN RIGHT THE FIRST TIME

wwmtlineman
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Re: Vacuum leak add power

Post by wwmtlineman » Fri Jun 15, 2018 11:51 am

Worked back in the late 60s for NHRA stockers until they caught on and used a sniffer to check them. A lot of 2 barrel cars slowed down after that. They would idle around in a black cloud of rich mixtures

RCJ
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Re: Vacuum leak add power

Post by RCJ » Sat Jun 16, 2018 8:08 am

Carb , but how would a plate be different?

Fireonthemountain
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Re: Vacuum leak add power

Post by Fireonthemountain » Sun Jun 17, 2018 12:46 pm

wwmtlineman wrote:
Fri Jun 15, 2018 11:51 am
Worked back in the late 60s for NHRA stockers until they caught on and used a sniffer to check them. A lot of 2 barrel cars slowed down after that. They would idle around in a black cloud of rich mixtures
3 deuces cars used it as well then. I have thought of other leaks that might be beneficial in a similar way without changing or raising idle mixtures. My head is still stuck back then in many ways, in my thinking.

pamotorman
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Re: Vacuum leak add power

Post by pamotorman » Sun Jun 17, 2018 1:15 pm

put on a fake vented inside the car power brake reservoir with a vacuum line to back of the carb base. you can close the leak inside the car for tech inspection.

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Re: Vacuum leak add power

Post by pamotorman » Sun Jun 17, 2018 6:09 pm

Fireonthemountain wrote:
Sun Jun 17, 2018 12:46 pm
wwmtlineman wrote:
Fri Jun 15, 2018 11:51 am
Worked back in the late 60s for NHRA stockers until they caught on and used a sniffer to check them. A lot of 2 barrel cars slowed down after that. They would idle around in a black cloud of rich mixtures
3 deuces cars used it as well then. I have thought of other leaks that might be beneficial in a similar way without changing or raising idle mixtures. My head is still stuck back then in many ways, in my thinking.
just enlarge the power valve fuel feed drilling and it will not affect the idle richness as you are only looking to richen up wide open throttle.

Fireonthemountain
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Re: Vacuum leak add power

Post by Fireonthemountain » Mon Jun 18, 2018 2:07 am

pamotorman wrote:
Sun Jun 17, 2018 6:09 pm
Fireonthemountain wrote:
Sun Jun 17, 2018 12:46 pm
wwmtlineman wrote:
Fri Jun 15, 2018 11:51 am
Worked back in the late 60s for NHRA stockers until they caught on and used a sniffer to check them. A lot of 2 barrel cars slowed down after that. They would idle around in a black cloud of rich mixtures
3 deuces cars used it as well then. I have thought of other leaks that might be beneficial in a similar way without changing or raising idle mixtures. My head is still stuck back then in many ways, in my thinking.
just enlarge the power valve fuel feed drilling and it will not affect the idle richness as you are only looking to richen up wide open throttle.
Or have the leak above the blades.......

shiftbyear
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Re: Vacuum leak add power

Post by shiftbyear » Mon Jun 18, 2018 3:53 am

I read an article some years back of a nascar team that got penalized for running hollow intake manifold bolts, the bolts were also drilled just under the head to provide an airpath. Desperate times....

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