Do I Need A Vacuum Canister?
Thread Starter
Safety Car
Joined: Aug 2000
Posts: 3,909
Likes: 26
From: Clymer PA
Do I Need A Vacuum Canister?
With my old 454 that had worked over O-ports, Holley Strip Dominator single plane intake, Holley 850 double pumper and Comp Cams 294S solid flat tappet .595/.595 lift, 250 @ .50 duration, 294 advertised I never had any vacuum issues. I switched to 320cc aluminum r-ports, Weiand Team G Intake, Holley 1050 Dominator and kept the same 294S cam....now I have vacuum issues out the butt lol. My headlights will sometimes struggle to go up (usually only one makes it up) and I have to manually put them up. The power brakes don't seem to have any issues. Does that sound like low vacuum signal? I haven't put a vacuum guage on it yet to see what kind of vacuum it is pulling. Thanks!
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
Check all of the vacuum hoses related to the headlamp system to see that they are all connected properly. There must be a hose not connected or a bad vacuum leak (intake gaskets?) in the intake area.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
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From: Las Vegas - Just stop perpetuating myths please.
U have a vac can in the front cross tube. That big tube behind the front bumber is a vac reservoir and in should be in use with the normal vacuum line up.
Sounds more like u have a vacuum leak from the head and intake swap.
Sounds more like u have a vacuum leak from the head and intake swap.
2026 Loser of the Year
Joined: Sep 2013
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From: New Or-leens Loo-z-anna
Rookie opinion: A vacuum canister would help you by "storing" enough vacuum to operate the lights.....provided the engine produces enough vacuum.
But first you need to solve the vacuum problem.
Let us know what you discover.
But first you need to solve the vacuum problem.
Let us know what you discover.
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
your asking for help diagnosing a vaccum problem?
yet, you have not done the first step...check the base vaccum.
I am betting a vaccum leak. from your intake install.
base vacuum less than 10" will be a problem, for vacuum driven componets.
yet, you have not done the first step...check the base vaccum.
I am betting a vaccum leak. from your intake install.
base vacuum less than 10" will be a problem, for vacuum driven componets.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
A little more vacuum could be just an idle mixture screw adjustment away...as my Granpappy up in Maine used to say "Hard sayin', not knowin'." Get your hands on a vacuum gauge, and adjust the idle mixture screws and the idle speed adjustment for highest vacuum. Ignition timing can be optimized for increased vacuum at idle, also. Don't tell me...you haven't measured that either, right?
Here's a link to a good article on how to put a vacuum gauge to good use once you procure one:
http://www.secondchancegarage.com/public/186.cfm
In the meantime, check for vacuum leaks. Here's another link that shows how your headlight system actually works:
http://forums.corvetteforum.com/c3-t...tem-works.html
Scott
Here's a link to a good article on how to put a vacuum gauge to good use once you procure one:
http://www.secondchancegarage.com/public/186.cfm
In the meantime, check for vacuum leaks. Here's another link that shows how your headlight system actually works:
http://forums.corvetteforum.com/c3-t...tem-works.html
Scott
