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idle vacuum psi

Posted: Sun Jan 26, 2014 3:38 am
by turbo970
i been reading some threads and was wondering if -12 psi was a normal idle reading on a boost gauge. i read a few threads where others were having -18 psi at idle

Re: idle vacuum psi

Posted: Sun Jan 26, 2014 5:17 am
by alexandermf
Me and Chris both run around 16-19 mine usually hovers over 18 with a warmed up idle. But i think our altitude has something to do with it vs vac readings at sea level


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Re: idle vacuum psi

Posted: Sun Jan 26, 2014 5:18 am
by turbo970
i'm at 7000 ft above sea level but running a stock turbo

Re: idle vacuum psi

Posted: Sun Jan 26, 2014 5:55 am
by James614
I pull 17-18 near idle. Id guess you have a vacuum leak.

Re: idle vacuum psi

Posted: Sun Jan 26, 2014 5:59 am
by matt00rs25
19-20 and I'm right at sea level

Re: idle vacuum psi

Posted: Sun Jan 26, 2014 10:13 pm
by Legacy777
Idle vacuum is going to vary on elevation. Check out this post for the ambient pressure at different altitudes.

http://bbs.legacycentral.org/viewtopic. ... on#p381936

I think 12 in-hg is probably a little lower than it should be.

Re: idle vacuum psi

Posted: Mon Jan 27, 2014 2:22 am
by turbo970
i went threw all the vacuum lines today replaced 2 and zip tied them all. now at idle it reads -14 i cant figure out why it wont hit -18.

Re: idle vacuum psi

Posted: Mon Jan 27, 2014 8:03 am
by lucas
because pressure altitude lowers it.

Re: idle vacuum psi

Posted: Mon Jan 27, 2014 7:43 pm
by Legacy777
Your vacuum reading of around 14 in-hg is about where it should be for 7,000 ft.

Re: idle vacuum psi

Posted: Mon Jan 27, 2014 8:54 pm
by turbo970
it kind of bounces but it runs fine. i did notice my brake pedal got firmer after replacing the 2 vacuum lines. and the boost comes in a lil sooner. just wish i had the funds to do the td04 up grade