boost gauge reading at idle ?

[hoopsbhoy]

ha ha well search for a thread here. mine was reading -12psi on idle and i was informed I most likely had a leak somewhere. I DID. fixed it, now it reads -17psi on idle, which is about correct. According to many people who know more than me, including mechanics.

[topdog]

How do you mean the engine is on over run? Vacuum is the same but opposite if you know what I mean. Think of it this way, picture the vacuum pipe going from his guage to the engine, When his guage is reading 5 psi, in that pipe there is air acting outwards with a force of 5 psi. Thats 5 psi above atmospheric pressure (atmospheric pressure on the guage being 0). But when his guage is reading vacuum, it just means that there is no pressure in the pipe, but there is a pressure acting on the pipe, (atmospheric pressure) and its measured as its still pressure as bar or psi but just as a negative figure.

[topdog]

ha ha well search for a thread here. mine was reading -12psi on idle and i was informed I most likely had a leak somewhere. I DID. fixed it, now it reads -17psi on idle, which is about correct. According to many people who know more than me, including mechanics.

Not saying your car isnt reading -17psi on idle but ive seen lots of turbo cars and never saw a boost guage read that low on idle. I have an apexi boost guage and it only goes down as far as -1 bar? Maybe it has got to do with setup or something maybe?

[Johnie]

Wow what happened here lol...
Damo1 if you read the thread the guy has fixed his problem... and what do you mean you don't read vacuum in bar only pressure in bar lol... how do you read vacuum if not as a pressure?

[20vees]

jees some moderation here lads , i fixed the problem. a muppet before me had the car and had it plumbed in the wrong way...it was on the line from intercooler piping and not on the bov piping like it was supposed to be.
close this up before it kicks off again LOL..thanks for the help too lads

[hoopsbhoy]

Not saying your car isnt reading -17psi on idle but ive seen lots of turbo cars and never saw a boost guage read that low on idle. I have an apexi boost guage and it only goes down as far as -1 bar? Maybe it has got to do with setup or something maybe?

I cant say I know enough to understand it.

EDIT: I think my guage reads boost in psi and vacuum in "in-hg", which would make sense from what your saying, I just never realised the difference and read it in psi, so when I was told it was correct I thought that was the PSI.

So -17 in-hg would be -.58bar???

anyone tell me once and for all what is boost on a standard sr20???

@ 20vees, glad you got it sorted, nothing worse than little annoying problems like that

[topdog]

Yup -.58 bar is spot on more or less same as my own. Can be confusing alright like I said my apexi guage reads in kPa?! Glad this is sorted and apologies to 20vees for the spam!
Glad you got your car sorted! Go drive the shit out of it!