What are normal vacuum #'s

['89beretta]

The car's a little rough at idle and when the clutch is in. Just started this morning. I'm reading 14-15 vacuum on the boost gauge. Would a rough idle be the result of a vacuum leak? I haven't pressurized the intake. Otherwise the car is running strong.

Gimme your thoughts. Thanks.

 

[greeneclipse]

mine sits at about 15-16.

 

['89beretta]

do you have any problems with the vacuum being around 15-16? I've noticed on my brother's SRT-4 that his sits at around 17-18. Mine used to sit at 16.

 

[Gigaah]

I vac 19-20 at idle. Southern WI. I hear it varies by altitude some.

I've heard vac leaks can be the cause of an array of problems.

 

[IMMORTALSPYDER]

Mine's 20 at idle.

 

[blcknspo0ln]

mine idles at 16-18 depending on the weather.

could be a leak somewhere

 

[Defiant]

Yeah, look for a leak. That's a couple inches low.

 

['89beretta]

Thanks for the reply guys. Anyway, does anyone have that link to the diagram on how to plug vacumm lines? I saw it awhile ago.

 

[heavyD]

Depends on altitude. I only have 12 but that is because I have cams and Calgary's altitude is among the highest of cities in North America at 3,444 feet above sea level. :thumbdown

 

[wishful_laser]

wow, mine sits at about 12 all the time and i live in fort worth texas. not to high above sea level. where should i start to look for a vac. leak?

 

[cfisher]

mine is normally 20 at idle. every once in awhile it will go up to 18 or so and then drop back to 20. i already removed the egr so i'm not sure if i have a leak or not.

 

[olmytsi]

mine varies between -15 and -20 is dat not right, should it always vaccum at the same place? mine varies like almost daily. do boost leaks affect vaccuum readings? meaning if i do a boost leak test and find a few leaks and fix them should my vaccum become steady?

 

[fulanititoo8198]

My idle is around -20,-30 am I missing something?

 

[wishful_laser]

i dont know alot about vac. pressure but all im saying is that my mine is about 12 all the time and after looking at everybody elses, that seems kinda low do you think? i dont know if i got a leak or not. that is where mine stays

 

[blaster1812]

Mine idels at 20

 

['89beretta]

I brought up the question because usually mine would sit right at 16, without any variation from day to day. However, recently it has dropped to 14-15, and the car idles a little rougher. Doesn't seem to affect anything under acceleration. Although I'm sure I have boost leaks somewhere, which would explain why I'm only trapping 96-97 mph with turboback and boost set @ 15 on a FWD.

 

[gsxtacy]

My 98' GSX (mods in profile) idles with 18 hg vac.. if the A/C is on around 20 hg vac.
750 rpm no A/C, 840-900 with A/C on.

gsxtacy

 

[zhjiln]

My 98' GSX (mods in profile) idles with 18 hg vac.. if the A/C is on around 20 hg vac.
750 rpm no A/C, 840-900 with A/C on.

gsxtacy

hmm..thats interesting... i get 18 inhg when idle ...but only 15 inhg with the A/C running....
i wonder why yours goes up with the A/C on but mine goes down....

 

[JMiller]

Mine idles around 15-17 at 500rpms with 272s and a vented ssqv type 2 bov(Blowthrough setup coming soon)

 

[snowborder714]

What's it with people and digging up really old threads lately? WTF

You must be logged in to view this image or video.

Wow that image brings back some good memories...

 

[rstare]

What's it with people and digging up really old threads lately? WTF

You must be logged in to view this image or video.

Wow that image brings back some good memories...

Lol, that is awesome.
I am going to borrow that picture for future use... hope you don't mind.

 

[rich3389]

Its funny because if he would have started a new thread everyone would tell him to search!

 

[Jeff99GS]

Its funny because if he would have started a new thread everyone would tell him to search!

1+ I was thinking the exact same thing.

 

[Defiant]

It all "depends".

In this case, no.