Question on vacum...

[ETTInnov04]

How much vacum are you guys running? Where is it supposed to be? I believe I have a small vacum leak, when at idle the car is running about 18-19psi per the boost gauge.

[9240sx]

That sounds right,Im getting about the same as you.

[ETTInnov04]

Nobody else has a boost gauge??? Not to say that I dont trust you: 9240sx, I just wanted... an average I guess. My car seems to stutter in second as boost comes on, when accelerating from 2000rpms, like a boost leak. I figured I could tell by the vacum reading in the boost gauge, so just curious as to what the normal reading is.

[9240sx]

How much psi are you hitting?Could be your spark plugs or the gap.

[nismostate]

I run 20-21 vac. with smic

[pgt892]

I run 16-18 vaccuum. Stock SMIC.

[LSB_11]

i was running about 19 with a fmic with autometer boost gauge ran through window, not mounted with line through firewal, which really doesnt make a difference, just to note it.

[ETTInnov04]

Thanks guys! Well I got my front mount installed last night and I'm still at 19. I'm running 10psi of boost (via a mbc) and I did notice that with the FMIC the boost doesn't fluctuate like it used to. Although it still stutters coming into boost, so maybe I will recheck the plugs.

[IanS]

Im guessing I have a vacume leak, Im only pulling about 9 in on Idle, Ive checked all my lines but I cant seem to find anything.

[S13240]

Of course everyone is going to run different vacuums as we're not all at the same sea level.

[Luke]

My vacuum usually shows 16-19 in/Hg on the autometer boost gauge at idle. Although my gauge isn't 100% accurate, i think i need to send it to autometer to recalibrate it (i think they do this for free).

[Nicksemianiw]

At idel i get maybe 12-14 PSI on vac but i dont know weather that is because it is a Ractive boost gauge or i have a vac leak. And if you have to know it was given to me for a gift Or it could be because i had a HUGE exhaust manifold leak, that might have had somthing to do with it lol.

EDIT: LSB_11 you said that if the line is through the firewall it can make a differance....how much of a differance would it be sending me more or less then i really have?

[Luke]

I'm not tryin to troll, but vacuum isn't measured in PSI guys. Most gauges show In./Hg (Inches of Mercury it can pull)

[llteddy4playll]

My vacuum is like 25? Is that too much but my car running good.

[travisn]

you might have an i-c hose that has a small hole in it, at idle the hole isnt big enough to over come the strength of the silicone, but under boost the air finds a way out. also, exhaust leak (of any kind) wont affect vacuum because the intake is sealed from the exhaust ( unless your turbo is horribly bad, lol) my sr has always had like 18-19 on my autometer phantom gauge, on my stock manifold and when i tried to put a stainless manifold on in my driveway without taking the turbo out so all 4 turbo bolts couldnt be tightened, so its hella loud, still has 18hg. ill get it fixed when i swap engines out of my rot box and into a better 240.