bottom vac hose has come off primary turbo.

[b4 freak]

hi, i have just put a new boost gauge in my 99 b4 twin turbo. i noticed that the bottom vacuum hose coming out of the primary turbo (no idea what it is for or is called) has come off and i cant get it back on as its right under everything. i didn't knock it off so it must of been like that for some time and it still seems to be going fine??? i managed to get it back on and it made the boost gauge work so it was obviously leaking pressure and after giving it a bit of a thrash round the suburbs i noticed the boost gauge stopped working again so i checked the vacuum hose and sure enough it had blown off... is this bottom hose important for normal turbo operation? the only way i think I'm going to be able to put it back on is to remove the black hose coming out of the top mount, is this easy to do? is water going to piss out everywhere? cheers for any advice guys. i haven't taken a top mount off before and Ive heard there a real bitch to do so I'm trying to avoid that atm...

[b4 freak]

alright so i took it to a mechanic and got it put back on. the hose had a re-stricter in it and he wasnt sure why there was one in there? he put a new hose in and hooked it up but now it doesn't seem to be boosting anywhere near as hard as what it was before? im tempted to just rip it off and just seal the hose up. is this was twin turbos are meant to be like? only one i have driven so i cant compare... just seems so slow 1st and 2nd gear to red line isnt pinning me back or anything...

[Airgne]

your goin to have to wait for the twin turbo ppl to pop there head in.

did he take out the restricter when he put the new hose on?

[Reuben]

"Derp, what's this restrictor doing in here? I know, i'll take it out! HERPIDY DERP DERP." - Your mechanic

Given your problematic vac lines lacation near the turbo, and the fact it had a pill in it, i'm going to say it's the wastegate vac line, probably the most important vac line in the whole system! I'm actually shocked and horrified your mechanic didn't know what the pill was for, NEVER EVER go back to him!! Cause restrictor pills are in most turbo cars, they play a part in what boost your car runs, single turbo or twin turbo alike.

Ring your mechanic and ask if he took the restrictor pill out, cause if he did, he needs to find it and put it back in. If he doesn't replace it, he's liable if your engine blows up, as the restrictor pill is part of the boost control system. In other words, without it, you could over boost, or get boost spikes, which can kill engines (especially if you use cheap fuel) (that's absolute worst case scenario).

Ring him now. Do it.


Where do you live btw, what country?

[Airgne]

well damn ruben i thought i was way off, but it looks like i wasnt. i just didnt want to say it if i was wrong.

[Robbks]

I'm with reuben.
sweedish chef mechanic.. (very funny)

EVERY vacuum line in the TT system IS VERY important.
here is some helpful info about your TT system and how it's plumbed up (look at the primary turbo and boost control solenoid areas)
http://www.veloce.pwp.blueyonder.co.uk/ ... opprt2.htm (http://www.veloce.pwp.blueyonder.co.uk/Twin%20Turbo%20Operation/ttopprt2.htm)

-using that, i suggest you remove the vacuum lines that run from the turbo outlet and wastegate actuator to the boost control solenoid
-fit a manual boost controller between the compressor outlet on the primary turbo and it's wastegate
-plumb the boost gauge into one of the nipples on the front of the manifold
-set your boost with the MBC to the desired level (14 psi for primary turbo only, this should rise to 16psi when in twin-turbo range (4000rpm+)

[b4 freak]

Where do you live btw, what country?

Hi, thanks for everyone's help. i live in Christchurch bud, nz. :)


thanks for that link just had a read through and from the looks of it its the negative preasure port

would this effect the amount of boost though? my boost gauge is only reading 6psi at 3500rpm (primary turbo).


thanks for all your advice guys.

[Reuben]

Yes, taking the pill out will affect boost pressure, when using factory boost control. I said you could over boost or boost spike, just to fear monger you into getting that pill back in there, and give you a sense of how important they are. Taking the pill out will actually reduce boost as far as i know, and bring it closer to wastegate pressure. However, i don't know fully how it all works, and it may indeed become susceptible to spikes. You can keep the new vac hose btw, just so long as you stick the pill in there! Note that they are only required for factory boost. Aftermarket boost controlers do not require the restrictor pills.

When you get the pill back in there, you should see 12-14psi on primary, and about 16 psi on secondary.

Take the car to Armstrong Subaru from now on btw, it may be a bit more pricy, but they know what they are doing! They will probably give you a discount too, if you say you're with Clubsub.

[Robbks]

thanks for that link just had a read through and from the looks of it its the negative preasure port


the Negative Pressure Port is on the Exhaust Control Valve which is attached to the secondary turbo's up-pipe (on the drivers side)

your primary turbo and it's wastegate is on the passenger side of the car...?

but as above, restrictor pill is needed for correct operation of everything.
there is another restrictor pill in the solenoid box aswell.
so be careful when changing any vac lines on these TT's
if you get the lines in the wrong place or remove the restrictors, they will not perform correctly

[Reuben]

if you get the lines in the wrong place or remove the restrictors, they will not perform correctly

Rofl. Yeah, understatement of the century.