boost and vacuum piping.

PurpleSnow · Post by **PurpleSnow** » 05 Apr 2018, 12:27

hi there

I just got a 94 850 t5 manual sedan just a while ago and im having trouble with the vacuum lines.
I had one that was off on the turbo on the compressor, when i was searching for the boost gauge line.

so I started searching for diagrams and found one on the forum that looks like a factory sticker.

: 2000 V70XC Vacuum hose diagram.JPG (81.76 KiB) Viewed 2347 times

So i switched all the pipes like on the picture. red on compressor where there was no pipe, yellow on
waste-gate and the blue to intake pipe and the bypass pipe to the vacuum tree.

I disconected the cruise controll as well seeing as the wires were all of will sort that out when i have the boost pipes fixed

So the next day i drove the car had almost double the power but it felt like it was boosting way too low
and too much.

now like i have them now as i got the car where the car feels ok and still boosting and dumping.

Blue on intake pipe
red on wastegate
yellow on pypass
and just the gauge on compressor,

but all the info and help will he helpfull
Im going to look for a after market boost gauge so i can see what the car does.
as it is now the gauge shows that it is boosting in half of the gauge on the boost side.

please help im stupid this is my first turbo car and I know you are laughing at me which i can take lol

Post by **abscate** » 05 Apr 2018, 14:09

So i switched all the pipes like on the picture. red on compressor where there was no pipe, yellow on
waste-gate and the blue to intake pipe and the bypass pipe to the vacuum tree.

This is right. The other way the compressor is boosting direct to the turbo which will drive it to max boost then dump the CBV.

On edit - that setup above will have no boost.

We are laughing with you, not at you. Seriously, Matts is a no-judging place. We once had an idiot here who put his air bags in backwards.

PurpleSnow · Post by **PurpleSnow** » 05 Apr 2018, 22:21

but now my question is on that setup the car pulls very strong. when i put my lead foot on the pedal it starts spinning instantly. im not really sure how the car should perform in correct conditions.
if i put a boost gauge on what should the standard boost be. psi/bar

Post by **abscate** » 06 Apr 2018, 01:58

You need pressure on the wastegate to produce boost. Without red hose from compressor there is no pressure to have.

If the wastegate is faulty of course, it could be boosting constantly.

I would start with a wastegate adjustment before I proceeded here.

Post by **rguzz** » 06 Apr 2018, 06:51

Do Something like this, with the wastegate on the car. I use my brake bleeder and it's gauge to test mine. Mityvac should work. Diaphragm was broken, no vacuum, so replaced it with one from Ebay. There are numerous Youtube videos, Robert DIY links to adjusting properly, pretty easy even for me. 4.4 PSI on the rod, if I recall, though I did 6 PSI.

Post by **abscate** » 06 Apr 2018, 07:12

Simple test - pull the wastage lever off the turbo and make sure the spring is pulling it back to closed. If its loose, the turbo boost will be uncontrolled, which could explain symptoms.

The lever can also just fall off, of course.

The wastegate adjust pressure varies with turbo model - there is a chart in the VRD

Post by **wizechatmgr** » 06 Apr 2018, 19:07

CBV/bypass should go to intake manifold directly.

From your sticker posted above:
Red to compressor (turbo)
Yellow to wastegate valve (the one with the long arm...)
[You should be able to pull vacuum on wastegate with a pump]
Blue is just a dump into the fresh air snorkel and should breathe freely.

PurpleSnow · Post by **PurpleSnow** » 07 Apr 2018, 13:11

i replaced all the pipes with new ones and added a after market boost gauge. everything seems to work now
and i can see the boost on the gauge is about 0.6- 0.7.

the waste-gate works perfectly. I also found that the pcv valve was blocked as well. new pipes to that as well.

the car drives very clean and boosts good. thanxs for al the info and help guys.

now just to fix my speedo problem

Post by **FLXC90** » 07 Apr 2018, 14:27

PurpleSnow wrote: ↑07 Apr 2018, 13:11 i replaced all the pipes with new ones and added a after market boost gauge. everything seems to work now
and i can see the boost on the gauge is about 0.6- 0.7.

the waste-gate works perfectly. I also found that the pcv valve was blocked as well. new pipes to that as well.

the car drives very clean and boosts good. thanxs for al the info and help guys.

now just to fix my speedo problem

Problem is it keeps going up too fast!!!

PurpleSnow · Post by **PurpleSnow** » 07 Apr 2018, 23:30

No it doesn't work at all. there is a newer transmission in the car that doesn't have a speed sensor on the diff.