-10 to -15 on boost gauge at idle???

[TurboDreamzGST]

Hey when I'm idling, my boost gauge will only read about -10 to about -15 and many people have told me it should be much higher than that, like around -20. Can anyone help me out and let me know why I'm having this problem? I have no boost leak and all my vaccuum lines seem to be ok. Please help.

 

[Artago]

Actually, I find it as fast as anything to type "convert bar to in Hg" into the Google search field. It responds with: "1 bar = 29.5333727 inches of mercury" along with some other useful links. And that gives you the exact conversion factor in case you need an accurate number.

Similarly, if you type in, "convert 15 in Hg to bar", it responds with, "15 inches of mercury = 0.5079 bar". I've found it quite handy.

Yeah that's what I do. Google is great.

 

[ricktb]

When I cold start my car, the engine likes to idle higher around 1300-1400 at which time the vacuum is at around 13-15hg. Once the engine warms up the idle drops down to 800-900, and the vacuum raises to 18-19hg. I think if your idle is too high the vacuum will be too low, aside from vacuum leaks. I'm only guessing on this

 

[mitsu29]

Actually, I find it as fast as anything to type "convert bar to in Hg" into the Google search field. It responds with: "1 bar = 29.5333727 inches of mercury" along with some other useful links. And that gives you the exact conversion factor in case you need an accurate number.

Similarly, if you type in, "convert 15 in Hg to bar", it responds with, "15 inches of mercury = 0.5079 bar". I've found it quite handy.

Normally i would have done the same thing, but i did not know what metric the vacuum side was on my boost gauge as it didnt give a 'in HG" label or anything..

 

[Artago]

When I cold start my car, the engine likes to idle higher around 1300-1400 at which time the vacuum is at around 13-15hg. Once the engine warms up the idle drops down to 800-900, and the vacuum raises to 18-19hg. I think if your idle is too high the vacuum will be too low, aside from vacuum leaks. I'm only guessing on this

You're idle is lower at higher idle RPM's ?!?!?! Shouldn't it be the other way around. At 900 RPM idle i have about 14 HG vac, at 1500 RPM I have 20 HG vac. Maybe it's due to the car being cold. You may have a tiny Vac leak which seals up as the car warms up. Any thoughts?

 

[CompuBob_TSi]

I'm at -21 idle on my DD Talon
My other talon on the other hand is only -12 to -15.. I need to check for leaks and compression.

 

[kenamond]

Normally i would have done the same thing, but i did not know what metric the vacuum side was on my boost gauge as it didnt give a 'in HG" label or anything..

It took me over a year to notice that my boost gauge had vaccuum in in-Hg, so that makes me think it's easy to miss. It dawned on me as I was wondering how you could possibly have greater than -14.7psi vaccuum. Then I noticed that ticks on the boost side weren't spaced the same as ticks on the vaccuum side. Then I saw the tiny "in Hg" and everything made sense.