what are your boost guages running in vacume?
 

as above. my boost guage is always on the highest vacume reading on tickover,is this correct? thanks

-0.7 bar

on tickover mine reads negative pressure 20-25,on the overun it reads a little more,poss -30......would depend on the boost gauge though i think

cheers, when i first fitted the guage it was ticking over on -20 and bosting at over 20 psi but now its started ticking over at -30 and bosting only 10 psi but the car still feels like its boosting the same. any ideas?

strange..... if its showing less boost but feels the same id say your gauge is playing up,as the difference in your previous readings and what you have now would, i think be easily felt as summat is not quite right.... same as the negative pressure differences you now have on tickover...... though is this all since you changed the motor spec or from before?

iv just fitted a hks turbo timer that has a boost gauge at tickover it reads 0 and when you rev it it goes up to 2.7 its mesured in hg cm or something could i have plumbed it in wrong i cut the small pipe between the wastgate and boost selonoide and fitted a t peice and connected it there is this correct oh its a uk my99

what he said

-20ish on tickover bit more on run over. Boosts 18ish. 03wrx.

ive taken the pipe off the manifold and blanked it off to see what the guage reads,surely it should go to 0 at this point? it dosnt it goes up and down. im pi**ed off cause ive thrown all the packing away.

Yep i'd say something is wrong there, as im sure thats what my Blitz boost controller measures in and it's basically the same as reading in BAR. You should have negative on tick over (i think about -0.5) and if your car is running standard boost about +1 on full boost. Not sure where mine is plumbed into coz i didn't fit but i'll try and have a look when i get my car back today

thanks m8 i wasnt sure where to plumb it to but figured the boost solonoid would be getting a feed of presure maybe someone else can shed some light on this ???

but could do with knowing iv got it rite ???

i just connected my boost vacume pipe strait to the inlet manifold mate

-20'ish

0.6-0.7 bar

Think what is 'correct' depends on the specific gauges you have as different ones have different scales.

On my Greddy ones, when you turn the ignition ( but not the engine ) on, the needle goes to 0 - on idle it will show about -700 ( 0.7 bar I assume ) then will read out as normal as the boost increases.

If yours is showing the highest boost on tickover then there is definitely something wrong - might be worth getting a new gauge fitted if the car feels normal when accelerating.

You will get a wrong reading from there, The solinoid pulses the signal pressure coming from the turbo output nipple and sends this to the wastegate so its never a true manifold pressure.

As others have already stated for best results take the feed off the inlet manifold there should be a blanked off nipple for this or cut the vacuum hose that runs to the dump vavle and take from there.

As for vac readings all depends on your engine at what altitude you are as all its reading in the natural atmospheric pressure at what level you are at........14odd psi at sea level, remember your gauge is set up for reading boost and not really vacuum so would not really worry just as long as it's fairly accurate as the system goes positive.