I installed my boost gauge couple of days ago... now the problem: I dont know if were i hooked up the hose of the gauge is were is supposed to be... I installed it on the (Looking at the engine from the front of the car) left hand side on the upper corner of the plenum, there is this kind of hook..., now when i put it there and did the rest, the boost gauge sits at 20 Vaccum... then somebody told me is not right... so i place the hose somewhere else, and put it to a hose comming from the bottom of the T/B, made a T .... Can somebody plz tell me if the boost gauge should sit at 0 or at 20 vaccum with the car on iddle? and where to put it....

 

Put it back where you had it. Anywhere on the plenum should do. 20 is right on.

 

allright doug apreciate.... so 20 is fine.... thanks.....

 

ya you have to understand...a engine is an incredible vaccuum pump in reality...so when youre sitting there at idle remember there is gunna be a vaccuum...0 = bad 20= greeeeeeaaaat lol

 

so is 20 where its supposed to be or 0..... didnt understand u ????

 

sorry 86...NO VACCUUM ON AN IDLEING ENGINE IS NOT GOOD....there should always be a vaccuum at idle..at 20...thats a high vaccuum but from what the other guy said 20 sounds ok...high but ok...if anything your engine is runnin good lol...i cant really help with turbo questions yet sorry i dont got one ...soon but not yet...im ok with em but when i get my z31t ill be better with this sorta stuff sorry otherwise

 

then y you answer to mine... jus be like im a N/A *****!!!! and that it,... just to let you know mine is on 18.... still high for you? then dont suffer..... jeje

 

im obviously helping more than you know with this subject...dont put down my responses

 

if you are still wondering about this, yes it is supposed to be at -20 psi at idle.

you have to understand how an engine works, and how the turbo works with the engine and how it affects it.

http://auto.howstuffworks.com/turbo.htm go read that article. It should explain why it is at 20 at idle.

In a nutcase, when at idle your engine is sucking air in on its own in order to continue running, hence the 20psi vaccumm. When you hit the gas exhaust hits your turbo's exhaust side impeller and spins it, spinning the compressor side which after spooling up builds up pressure to whatever psi it is set to. It will only continue creating boost as long as exhaust gases are spinning it. So when you ease off the gas it slows down and boost levels drop. If you let go of the gas pedal and close the throttle (like when you shift) the turbo is still spinning at very high RPM's (by high i mean around 10,000 or higher) and still creating pressure, but the pressure has nowhere to go (compressor at one end of intake, closed throttle at other end) this can cause damage to your turbo because it will stop your compressor from spinning very fast, causing physical shock to your turbo. (not good) It also means that your turbo has to spool all the way back up from nothing to create pressure again when you are back in gear. This is why you need a BOV it will release the excess pressure created in the pipe from the turbo to the throttle body when the throttle is closed quickly. By doing this it prevents shock to the turbo, your turbo is still spooled up from last gear and gets up to speed faster = less lag. Not to mention it sounds cool

I started running 12psi today with a blitz BOV plugged POV KnN and home built MBC, I don't yet have my intercooler, I plan to do that very very soon (as in within the next two weeks) and my exhaust is crappy as well. It is also on high priority. Then I'll keep it at that untill I replace the injectors, fuel pump, ecu, tb. That should get me close to 300. Where I'll be content and start working on making it look nice before going back to the motor.

 

same plans here

 

"if you are still wondering about this, yes it is supposed to be at -20 psi at idle."

Yep, like I said way back, 20 is good . It isn't 20psi though...