Who's done a boost leak test?

A

AudiB720TS

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I asked on Audizine previously and got mixed input, some of my questions never answered.
So I want to ask here as well: has anybody successfully done a boost leak test? If so I have a few things to confirm and a question.

Got a possible leak on my IC piping that I want to test for...

Thank you in advance
 

vag-tech

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Do them every other day...
 
A

AudiB720TS

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Do them every other day...

Great.
I started at a boost leak test a while back but aborted it because I was hearing this slurping/gurgling sound.
Like oil or fluid being pushed. I never got a clear answer if that sound was expected or not. I now need to test again because of having installed a new FMIC. Here is what I did before and maybe you can correct me or comment on this [sound] and procedure:

Boost Leak Test

Preparation:
  1. Disconnect turbo inlet hose from airbox,
  2. Connect boost leak test adapter (pipe plug with valve) into turbo inlet hose,
  3. Disconnect PCV hose from turbo to valve cover (at valve cover side) and plug with blank,
  4. PCV return to intake manifold plugged already (ECS catch can system).
Execution and Results:
  1. Charged/filled air compressor,
  2. Connector fitting with tire valve and pressure gauge (see picture) to plug with tire valve on turbo inlet hose,
  3. Started to pressurize the system (let fill for maybe 10-20 sec)
  4. Heard a rather loud gurgling sound so stopped filling,
  5. Noticed pressure in turbo inlet hose dropped
Questions:
  • Is that sound to be expected? What might have caused it?
  • How about the loss of pressure? Is it maybe that air just traveled further -maybe passed the some amount of oil with some effort (causing the sound) and then the pressure loss before that 'segment'?

@vag-tech Ideas on both of the above much welcome!

15hh4j5.jpg

Here you can see how I am filling air and that the PCV is plugged.

11kjnll.jpg

Here you see all plugs: inlet hose, PCV, and the PCV connection on the intake manifold (part of my ECS catch can setup)
 
A

AudiB720TS

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Before we go any further, why exactly are you doing a boost tract integrity test?

Installed a new FMIC so all new hoses from turbo and all the way to throttle body. I have not driven the car at WOT yet, but it does feel more sluggish.
Not turbo lag sluggish, just weaker over all at the moment. So my thinking is that one of the silicone couplers has got a leak on it.
 

vag-tech

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Pressure-test the full boost tract in isolation, from turbo including intercooler, cap off just before manifold where convenient.
Should be free from leaks. If you have a leak here, as you say, if it’s a new bits, go straight to the couplings. Smoke testing would be ideal.
 
A

AudiB720TS

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Thank you,
But that does not answer my question reg. strange gurgling sound, pressure drop, or whether I plugged things correctly.

Cheers!
 

I'm Just Rob.

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the sounds you were hearing, was this with the standard IC's fitted or the new one?
If with the old oem ones there maybe an obvious answer to the sound.
 

vag-tech

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Thank you,
But that does not answer my question reg. strange gurgling sound, pressure drop, or whether I plugged things correctly.

Cheers!
Connect up the way I suggest then report. Don't incorporate ancillary items in pressure test, just boost tract. Your pushing oil on account of incorrect setup.
 
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AudiB720TS

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Connect up the way I suggest then report. Don't incorporate ancillary items in pressure test, just boost tract. Your pushing oil on account of incorrect setup.

Not sure what you mean is different from what I did. You mean to connect after the turbo instead of in front of the turbo?
 

I'm Just Rob.

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This was on the stock SMICs.
Had you checked for oil residue in them , if you have been running with them uncleaned for any period of time they may have been oil in them , which may have accounted for the fluid sounds, its just another possibility.

rob
 
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AudiB720TS

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Had you checked for oil residue in them , if you have been running with them uncleaned for any period of time they may have been oil in them , which may have accounted for the fluid sounds, its just another possibility.

rob

I checked on deinstall: maybe .2 - .5 liters inside. Not enough to account for a loud gurgling sound. It really sounded like you push the content of the oil pan through the engine.
 
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AudiB720TS

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OK:
I talked to my mechanic today and he was kind enough to hand me his boost leak test tool. He got it from working at a Volvo factory so much nicer than my little contraption. Will test next weekend connecting the tool to the intercooler inlet hose instead of turbo inlet hose.
 
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