I know I've seen it before but can't seem to find it anywhere now. Does anyone know what the stock (non-chipped) levels are supposed to be for max boost pressure and idling manifold vacuum? I just installed my boost gauge and would like to be able to use it.

Also, how much does a chip increase the boost pressure? (primarily GIAC) Does a chip change the manifold vacuum at all?

 

stock boost is 8psi and chipped cars is 18psi depending on the chip provider i am unsure on the vacuum side my boost gauge reads -20 when at idle

 

Cool, thanks. While idling the needle jumps around a lot. Is this normal?

 

when im at idle and the car is fully warmed up my boost gauge just sits at -20

if the car hasn't fully warmed up it sits alittle higher at like -15

 

Mine sits at 19 psi warmed up with a/c on, and 20 without a/c, lol.

I took it for a test drive and in 3rd, 4th, and 5th gear at WOT it got to around 18 psi before dropping, although it did peak at 21 psi a couple of times. I'm guessing I have a mystery chip too. Is there any other explanation?

 

you can pull out the ecu and see if it has any kind of labeling on or has a soldered chip inside (rarely done on our cars)

my ecu has nothing on it or in it but i know that it is chipped

 

Just checked, and no. No labels or soldering of any kind. Now I'm stumped. Any advice to point me in the right direction of where my excessive boost is coming from?

 

you may be like me and have a mystery chip did you buy the car used??

 

Yeah.

 

11psi is stock for the 2001+ cars. Your car has most likely been flash tuned if you bought it used.


If you are seeing 18psi and up to 21psi in 3rd/4th/5th gear then you most likely have a GIAC Xchip flash which was/is one of the more common flash tunes for the 2001.