15 psi vaccum at idle????
12-29-2007, 07:49 AM
#22
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29.92 " HG is ~~ 14.7 psi [earth's supercharger].
Unfortunately many are confused by a so called vacuum gauge and the reverse reading.
0" on the gauge is 14.7 psi and 20" on gauge is 14.7 minus [20/29.92 or 0.6685 x 14.7 ~~=9.8262 psi plenum pressure. [Corected for local barometer].
The resistance to atmospheric pressure is a function of the resistance of air filter , MAF, plumbing, TB and plate so rare to see more than 14.2 psi in plenum at WOT and ~~ 9.8 psi at idle cruise.
Then you add whatever pressure the add on super/turbo creates.
Engineers always use a positive pressure SCALE like kpascals [kPa] to avoid confusion.
Unfortunately many are confused by a so called vacuum gauge and the reverse reading.
0" on the gauge is 14.7 psi and 20" on gauge is 14.7 minus [20/29.92 or 0.6685 x 14.7 ~~=9.8262 psi plenum pressure. [Corected for local barometer].
The resistance to atmospheric pressure is a function of the resistance of air filter , MAF, plumbing, TB and plate so rare to see more than 14.2 psi in plenum at WOT and ~~ 9.8 psi at idle cruise.
Then you add whatever pressure the add on super/turbo creates.
Engineers always use a positive pressure SCALE like kpascals [kPa] to avoid confusion.
12-29-2007, 10:00 AM
#23
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Originally Posted by undrgnd
JoeDirtPharmD, if you're going to be a smart a$$, at least have your $hit together. Vacuum is measured in inches of mercury (inHG), not negative mm (mmHG).
I'm capable of much worse 
How 'bout this:
Originally Posted by str8dum1
Hey guys,
I have a vortech blower on my car and now I only see -381 mmHg at idle, where as pre-vortech I was seeing the normal -508 mmHg.
Would a vaccum leak cause the idle vacuum to be higher or lower (i.e. a leak would show up at -381 mmHg, not -508 mmHg??))
I have a vortech blower on my car and now I only see -381 mmHg at idle, where as pre-vortech I was seeing the normal -508 mmHg.
Would a vaccum leak cause the idle vacuum to be higher or lower (i.e. a leak would show up at -381 mmHg, not -508 mmHg??))
Last edited by JoeDirtPharmD; 12-29-2007 at 10:06 AM.
12-30-2007, 01:36 AM
#25
I haz da turbos
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Originally Posted by undrgnd
Last time I checked, both Raleigh and Phoenix were in the greatest country on Earth, the United States of America.
12-30-2007, 01:39 AM
#26
I haz da turbos
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I also forgot. Not just Europe but pretty much everywhere else in the world too. Even in the states, when your working with anything not American, you use metric. Haha.
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