View Full Version : boost gauge reading at idle ?
what is the boost gauge on a s14 sr20det blacktop supposed to be at because mine is showing 0psi at idle with car cold and warmed up, my friends is at minus that .
i have changed my boost gauge to a name brand and still at 0psi, it boost fine up to .5bar max
any info would be great tanks
It could be connected to the wrong vacuum take off on your intake manifold.. ?
if its showing .5 at boost and 0bar at idle instead of minus psi [vacuum] what made you think i was on the wrong take off.....
does anyone have a blacktop vvt that can tell me what theres is reading so i can judge if mine is ok or not
I thought you might have it connected to the one for the carbon cannister or sometimes they can get blocked. No yours is not reading ok, why would you think it's not supposed to read vacuum and only read .5 psi boost? even standard it should read 7psi boost.
maybe i didnt fully explain it fully....a vacuum at idle[0bar or lower?] and boost when you accellerate[up to [.5pbar].
its on the right pipe ..i just need to know is it supposed to be at 0psi or lower and if its supposed to be lower ill fix the problem if there is any as i stated my friends redtop sr20det is running vacuum at idle...mine is not
Ok to clear this up, your problem is your boost gauge is not reading vacuum on Idle? but works ok on boost? Any aftermarket boost gauge should read vacuum at idle no matter what car you have. not sure is that what you're asking?
yes what is it supposed to read at idle how can this problem be fixed ...ive tried 2 boost gauges one brand new so where is the problem?
It should read the same as your buddy's red top or near enough. Try moving the boost gauge vacuum pipe to another take off and see what happens, it will only take you a few seconds to do and would rule that out.
S14a johno
09-07-11, 14:46
it not the boost gague mate, it how ya have it piped or boost leak
i have mine comeing off the BOV or the boost controller
tink boost controller, as it reads the presure as well
but defo should not be 0 bar on the gauge...........
at idle should be in the -.05 area of the gague the lowest part
Mine reads -.6 bar at idle, yours should read around the same I would imagine.
Why you being so tetchy man, you plainly have it plumbed wrong. And 5psi is not standard boost either.
You should be running arounf -17psi on idle for a start
plumbed wrong not by me bought the car and it wrecks my head everything is wrong and spending most of time fixing it instead of driving it...thanks for the help lads.
its reading -.6bar at idle and boost up to .5bar
No problem, I hope you mean bar and not psi.
yes you know it ha ha ha ill edit
Why you being so tetchy man, you plainly have it plumbed wrong. And 5psi is not standard boost either.
You should be running arounf -17psi on idle for a start
-17psi??? roughly -1.1bar at idle? not a chance, thats way to much should be -.6, -.7 thats about right
id say the vacuum pipe is plumed up the wrong way for ya lad.. go take a vacuum from the intake manifold and run it to your gauge..
@ topdog.. ya it defaintley shoudnt be -1.1bar as you don't read bar in vacuum you read bar in pressure smart man clap clap for you.. are you a mechanic ?
Vacuume is the same thing you muppet just on the other end of the scale so you read it as a negative figure pressure is above 0 on the bar or psi scale and vacuume is below 0 so read as a negative figure which is measured in bar, psi, can measure it in mmwg or even kPa if you want to. Doing instrumentation for the last 4 years dude wrong thing to be trying to correct me on. Clap clap for you
And just out of curiosity, what did you think was the unit for measuring vacuume??
lads lads lets be nice here hee hee...
so your telling me vacuum is the same this as pressure?? so when your engine is on over run it acts as a hoover sucking the air into the cylinders when on closed throttle,. is that how you also describe pressure??
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.
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.
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?
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?
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
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
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! :)
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