I've heard that you can detect a vacuum leak by reading your boost gauge at a waarm idle... when my car is all warmed up and idling, theboost gauge reads at 15 psi vacuum.... is this right?

 

my vacuum usually reads just below 20

 

hm... do you think that could mean tha tI've got a vacuum leak? Does it matter that i'm at 5800feet elevation? Everything is ran off of the fpr vacuum line... could this be the reason? What does this mean for my performance?

 

hmm.. i'm no expert on this.. but I do think that 5800' elevation could have something to do with it.

 

i wouldnt run everything out of you fpr vacuum.... try running some of the sources from the back of the intake manifold... it sounds like you might have a vacuum leak.... have you checked all of the lines?.... also have you adjusted your blowoff valve at all?

 

I have adjuested my bov.... I've made it "softer" (greddy type-s), but it hasn't had any effect on the pressure at idle. What all would be ok to run from the fpr vacuum line?

What would a vacuum leak do to my car/performance?

 

if you had a vacuum leak you would have an abnormal idle. I wouldn't think it would hinder the performance too much unless its related to your fmu or fuel pressure regulator...

when im checking for vacuum leaks i take each hose off one by one (while engine is running) and i listen to the engine as i put my thumb over the hole of the hose... usually the idle will smooth out as you cover it and drop when you let go.... if the idle is still irratic when holding your thumb over it, you found your leak...

 

that's a good idea.... I'll try that... but my idle seems fine now.... it sits right around 750rpms (once its completely heated up) and doesn't jump around or anything like that

 

when i was in calif before i went on vacation.. the vacume was at -20.. when i got to colorado, craig colorado to be exact.. it read around -15.. so i think altitude as something to do with it...

 

cool... that's exactly wha tI needed to know actually... I'm here in colorado springs, colorado so that's a good reference point. Thanks

 

I read an article that says in 1000 foot increments, starting at sea level, vacuum decreases by 1-2 in Hg. So 5800 ft, would decrease vacuum by 5 inHg. It was a great article I really need to scan it.

 

I'd be interested to see it if you get a chance

 

My mechanic is from Colorado Springs.

 

does he work at a local shop? Who is he?

 

me too please and thankyou...

but its true, the higher up you go, the lower the atmospheric pressure..!
there's less "air mass" (volumetrically speaking) pushing down.....

hense the lower Hg value at idle...
mines at 21 and im in toronto. canada.

hth..