hey what is the difference on a boost gauge between vac and psi can i get one with just psi have no clue but want to pick one up tomorrow and put it in thx ............

 

you want one with Vac also.

Vac will tell you how well your car is in vacuum when not accelerating/under boost (which is your psi).
It can tell you if you have a leak under vacuum.

 

A vac/boost guage is only a few dollars more than a boost gauge - well worth the extra $$.

Like brrman said, when you accelerate, you make boost (psi or bar). When you decelerate, you make vacuum (inches Hg).

You could have a leak in either direction.

 

I currently have a vac leak and it is driving me nuts.
I was picking around at the vacuum system last night and found a small crack in a hose leading from my n75 valve.
This morning I can't get any more than 5 psi. LOL - checked the vag on the way to work and realized I didn't plug the
n75 valve back in (N75 open circuit code)

 

oooo ok i get it now i had a feeling that was how it worked im on my way out to get an auto meter as soon as i take a shower ...... hopefully it is a decent one ..... welll thanks guys

 

just get the boost gauge it looks cooler than the vac/boost guage

 

heh heh...easy to say when you don't have a vacuum system.