Pressure testing Intake.. looking for Boost Leaks

[Haysey]

Hey all,

im thinking ive got a boost leak somewhere, ive made a different thread on my issues..
anyways ive made a boost leak tester that is similar to the AWE one, blocks off the intake just after the AFM... ill be running compressed air into it and looking for leaks whilst blocking off the little valve thingo which is just after the start of the Y pipe..
any other pointers, do's or dont's about testing the system?

im really thinking ive got a boost leak, the car is making boost really late like 2600ish, instead of the kick in the ass at 1800, and im thinking i can hear air leaking when its boosting too.. its not as quick as it used to be and up top its not punching through the rpm...

checked the afm using vag no error code
thinking it might be N75
checked DVs using suck test.. no leaks

stock except for SS Autochrome exhaust...

Thanks All

[Huminator]

typically n75 is going to cause overboost, but not always. test it to 15 psi or so at the intake and be vewwy vewwy quiet.

[RolledMySTi]

Definitely sounds like a boost leak.

Don't be quiet, spray the motor with soapy water. It's really hard to hear a boost leak. Bubbles make it easy to point out the exact spot of the boost leak. No more than 15 psi when you test it. Check your TBB first as it is a common problem.

Lots of luck.

[S4Per]

loosen your oil filler cap, too.

[Haysey]

replaced the TBB with an upgraded stocker, it blew ages ago and sounded like an external wastegate on full boost lol...
ill screw in a boost gauge to the tester so i dont go past 15psi

funny thing is it just happened over night pretty much... from normal fast to this shit semi limp mode kinda.. but its definately getting worse now..
ill cover the engine with soapy water but it will be hard to find a leak if its one of the ICs or something.
id love to make it a smoke tester but cant exactly go putting fireworks in there..
oil filler cap ...ok

how common are the rubber pipes between the turbos and what not in breaking?

i saw some oil coming out of one of the hose joins at the bottom of the pass side IC, dont know how long its been there for maybe a slow leak?

i replaced the fuel reg hose today as this had freyed and had a small leak which i discovered once i had it all off..

[The_Jerbel]

When you pressure test it, spray soapy water around the F-hose, the TBB, the DV's, the injectors, and the spider hose. That should reveal the little bastage.

[Haysey]

would a small boost leak be causing such problems? ive got visions of a tear in a cooler pipe somewhere!!...

the injectors? would they leak boost? huh?
where is the spider hose, ive heard it before but have no idea which one it is.. at the back of the block somewhere?

[AudiSportB5S4]

the spider hose is near the firewall behind the motor look down in that gap between Y pipe and the, in your case NOGARO firewall and it should like a few lines going into one place. usually if thats leaking there will be oil all around that area. if i were you i'd check the F hose, that thing went on me on my 2000 before my turbos blew =], so check it now! and also check to make sure everything is on tight. like my diverter valves at one time werent on as tight as they could of been and they were leaking air. so i took the hose off from the Y pipe and attached that mofo as tight as i can... look at this pic, i wasnt kidding!



then its easier to just put the DV back in on that hose just attach to the bipipe again and clamp it tighttt.

[black_bi-turbo]

Also check the vacuum line from the FPR. That's where i found my leak. The factory line was brittle and cracking. Hope this helps

[The_Jerbel]

Yeah sounds like a boost leak to me.

The spider hose doesn't necessarily blow oil all over when it leaks, it depends what part of it is leaking. It's the hose behind the intake manifold that has many lines converging into one.

The injector seals can leak vacuum/boost.

[Haysey]

Wow!!!

took the underpan off and i could see lots of oil on the passengers side cooler (your drivers side)

used my home made pressure tester!!! and found the end tank of the cooler had pretty much cracked off quite a bit! definately leaking alot! the system wasnt holding any boost at all! the last few days the car has seemed NA and this is why im guessing! its lucky that marco is doing a stage three conversion and i can have his old intercoolers free.. off to pick them up now! seems the intercooler has hit the horn and bent some fins at some stage of its life too.. weird....

thanks guys! ill let you know how i go!