suspected boost leak

[Greg_S]

Ive been servicing my car this week along with a couple of other bits like replacing the duff oil pressure sensor I fitted again!

Anyway I decided to test for boost leaks since the car hasnt been feeling as quick as it should so I used my bungs on the MAF to turbo hose and the pipe from the IC crossmember to the black pipe that goes to the throttle body hose.

Tested on there and it wouldnt hold any pressure.

So I bunged the breather hose that goes through the cam cover. I pumped up to 10 psi however it lost the pressure down to 8 psi in about 5 seconds and continued to go down.

I used some soap water on the intake pipe but couldnt see any bubbles from anywhere.

My questions are:

1. should it hold pressure through the breather system during testing?

2. Could pressure be leaking from WGFV to wastegate and through that way?

3. Where else is it likely to be?

[AAH!]

IIRC Lees kit is designed to be used with 3 bungs although he only supplied 2, the third being a socket wrench extension or similar in the breather hose that goes to the cam cover. if you don't put a bung in there the system wont hold pressure as the air escapes through that hose and comes out of the un-bunged throttle body.

Mine isn't totally totally air tight and doesn't hold constant pressure when tested with 3 bungs in place and after putting 1.5 bar in it slow drops off but holds at lower pressure for some time 0.6 bar-ish(?). I think the seals in the turbo can leak a bit, mine do and we have the same turbo, you can hear it bubbling sometimes when it is under pressure.

You could try pressure testing the whole system with just a single bung in the MAF position, this test the breather system as well. It wont hold full pressure and it will drop off but it may identify a leak in some of the small vac hoses.

If you do this be aware that when you start the car after it will be VERY smokey as pressure testing this way pushes oil into areas that don't normally see much. It does burn off but when I did it the first time it was a bit of a worry as I thought I'd damaged something.


HTH

Angus

[Greg_S]

Yeah I did the bung in the breather system too with a wrench when I realised it wasnt holding pressure. I wanted to double check I wasnt going mad with that testing. im looking at getting a custom metal intake pipe made too which should help.

[jon]

how much is your turbo leaking ? mine is leaking at 10 psi

[Greg_S]

Yeah about the same pressure. It seems to bleed away at a fairly steady rate. I couldnt work out where it could be from though.

I may try putting a bung on the WG hose and see what it is like then too.

[martin richards]

If your pressure testing the head as well, would'nt there be an exhuast valve open, therefore always losing some pressure, as mine does.
Martin

[martin richards]

Also im in shefford your welcome to try my WGFV valve as its brand new

[Greg_S]

is yours a red s2 coupe?