Installed a boost gauge, hardly any VAC?
#1
Installed a boost gauge, hardly any VAC?
So I installed a boost gauge on my 2004 ion redline. I ran the line and t'd it off the vac line comming up from behind the blower from the manifold. Now my boost holds perfectly at 12/13psi. My VAC is 6-10.. Any ideas? Wrong VAC line? My buddy said I may have blow-by? I've double checked for leaks, kinks, I have some Teflon tape at every connection to ensure its leakproof.
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I checked my vacuum this morning (on my ScanGauge II) 8.5 psi average at idle measure at different stops on my commute to work.
[that is @ 42 deg F, barometric pressure here: 29.49 in Hg]
While my scangauge read 8.5 psi vacuum, my boost gage was holding at ~17.5 in Hg. vacuum. A quick conversion from Google verifies: 8.5 pounds per square inch = 17.3081621 inches of mercury.
From this, I would venture a guess to say that 6-10 psi vacuum is likely just fine, I don't think you have any issues. Just for reference, the equivalent of 6-10 psi would be 12.2-20.4 in Hg.
[that is @ 42 deg F, barometric pressure here: 29.49 in Hg]
While my scangauge read 8.5 psi vacuum, my boost gage was holding at ~17.5 in Hg. vacuum. A quick conversion from Google verifies: 8.5 pounds per square inch = 17.3081621 inches of mercury.
From this, I would venture a guess to say that 6-10 psi vacuum is likely just fine, I don't think you have any issues. Just for reference, the equivalent of 6-10 psi would be 12.2-20.4 in Hg.
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Pressure can be measured in either PSI or Inches of Mercury (in Hg). The Cobalt SS/SC analog gages are twin-unit gages to view PSI units in boost (positive pressure) or in Hg in vacuum (negative pressure).
The vacuum can be displayed in either units. 17.3 in Hg (pressure) that I saw this morning on my analog gage is equivalent to 8.5 psi (pressure) that i saw on my Scangauge II. Both pressure, both vacuum, two different ways to report the same thing.
The vacuum can be displayed in either units. 17.3 in Hg (pressure) that I saw this morning on my analog gage is equivalent to 8.5 psi (pressure) that i saw on my Scangauge II. Both pressure, both vacuum, two different ways to report the same thing.
Last edited by JBMark33; 12-18-2012 at 11:52 AM.
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What RPM are you idling at?
I would park the car safely, set the e-brake and let it idle. Pop the hood and spray carb cleaner around all your vacuum lines. If you notice the engine idle up in a certain area, you may be able to determine the location of your VAC leak.
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Pressure can be measured in either PSI or Inches of Mercury (in Hg). The Cobalt SS/SC analog gages are twin-unit gages to view PSI units in boost (positive pressure) or in Hg in vacuum (negative pressure).
The vacuum can be displayed in either units. 17.3 in Hg (pressure) that I saw this morning on my analog gage is equivalent to 8.5 psi (pressure) that i saw on my Scangauge II. Both pressure, both vacuum, two different ways to report the same thing.
The vacuum can be displayed in either units. 17.3 in Hg (pressure) that I saw this morning on my analog gage is equivalent to 8.5 psi (pressure) that i saw on my Scangauge II. Both pressure, both vacuum, two different ways to report the same thing.
Last edited by mrbelvedere; 12-18-2012 at 03:52 PM.
#17
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Is it the gauge itself? I haven't seen the question posted yet. Does it go back to "0" with the engine off? Could be a broken gauge. If no to question #1, it definitely could be a vacuum leak. Boost leak test with soapy water to find the leak. SRT-4s are notorious for screwed up stock gauges (just sayin').
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So I installed a boost gauge on my 2004 ion redline. I ran the line and t'd it off the vac line comming up from behind the blower from the manifold. Now my boost holds perfectly at 12/13psi. My VAC is 6-10.. Any ideas? Wrong VAC line? My buddy said I may have blow-by? I've double checked for leaks, kinks, I have some Teflon tape at every connection to ensure its leakproof.
Is it the gauge itself? I haven't seen the question posted yet. Does it go back to "0" with the engine off? Could be a broken gauge. If no to question #1, it definitely could be a vacuum leak. Boost leak test with soapy water to find the leak. SRT-4s are notorious for screwed up stock gauges (just sayin').