Intake Pressure Test

[quattroboy]

Just done a Pressure Test with Lee's Kit on my AAN.

Blocked the Camcover Breather Pipe and put 10-15psi into the MAF Adapter.

No leaks present, or at least I don't think so anyway but I did hear air "escaping" through what appeared to be the Wastegate?

The Pipe running from the WGFV to the Banjo Bolt Union just under the Wastegate Top Cover was letting Air through. When I crimped this pipe the "escaping air" noise stopped, then started again when I released the pipe.

I have tested the Diaphram with the MityVac and it holds 20hg Vacuum.

The car pulls like a train with no problems apart from the turbo which seems to spool up with a longish whistle............probably because of the slush box maybe?

Whats all that about or is this "escaping air" noise normal?

Your thoughts are appreciated

Ta

Dave

[audiman]

You shouldnt get any air escaping AFAIK

[dkw_dude]

I have the same experience when pressure testing. And a hissing sound when turbo spools. The price of a new wastegate is insane (here in Norway equivalent to ~1000£+ ) so I'll put that on hold for a while.

Got hold of a used WG, but it was in no better condition. Have given it to a mate who works in a machine shop, he would take a look at it for me (try to make a new bushing for the valve). He's having trouble finding out exactly what material is used in the bushing though.

I'm also interrested in opinions on the subject.

[martinjs]

It air passsing through the seals of the turbo isnt it, mine does this, think paul n's does too.

[Dr H]

Mine makes a massive hissing sound when the turbo spools (as Paul N he's heard it!) but is only down about 0.1 bar on boost. Static pressure test reveals no leaks.

I've come to the conclusion that it's the EM, I reckon it's cracked. At cold start I sound like I have a slight 'blowing' noise and if you lift the bonnet you can smell exhaust fumes. Once things are warmed up it's fine but when you make it boost it sounds like it's loosing air.

[S2central.net]

Just done a Pressure Test with Lee's Kit on my AAN.

Blocked the Camcover Breather Pipe and put 10-15psi into the MAF Adapter.

No leaks present, or at least I don't think so anyway but I did hear air "escaping" through what appeared to be the Wastegate?

The Pipe running from the WGFV to the Banjo Bolt Union just under the Wastegate Top Cover was letting Air through. When I crimped this pipe the "escaping air" noise stopped, then started again when I released the pipe.

I have tested the Diaphram with the MityVac and it holds 20hg Vacuum.

The car pulls like a train with no problems apart from the turbo which seems to spool up with a longish whistle............probably because of the slush box maybe?

Whats all that about or is this "escaping air" noise normal?

Your thoughts are appreciated

Ta

Dave

What I think you are describing is normal. During a pressure test you should really blank off the control hose going to the WG. Reason being that pressurised air gets thru the WGFV in its position with the ignition off.

What has always weirded me it is that the control chamber of the WG is NOT supposed to be completely air tight - during such a pressure test, air always bleeds past the valve in the WG. I've proved this on several WG's just by connecting an air line to the control port and you can't sustain any sort of air pressure in the chamber. Mihnea has always assured me this is OK and normal.

Alternatively, the noise you might be hearing is pressurised air sneaking past the seals on the turbo input. Don't forget when you do this test thru the MAF hose that you are presenting air pressure at a hose which normally sees vacuum ALL the time. The turbo SUCKS air in thru the MAF hose remember and blows it out the output hose. That seal is not designed to withstand boost pressure. Mine leaks air there - you can hear it bubbling into the central housing actually.


Paul

[quattroboy]

Sounds like I have nothing to worry about then!?

You just gotta love this forum

Thanks for the replies guys. I will be testing another AAN very soon so it will be interesting to "listen" to those results.

Paul, I will blank that Wastegate Hose and have another fiddle about.

Will post my findings on the other AAN when test completed.

Ta very much

Dave

[Billman]

Where can i get this lee's kit! Any other topic with it? I htink i must do also a pressure test! Just to be sure!

Greetings

[horvathg]

Try to visualize your leak with cigarette or rather cigar smoke pumped into the system instead of air. It should make a hissing leak visible if you are lucky. Make your pump suck on the cigarette somehow . Makes no harm.

[quattroboy]

Where can i get this lee's kit! Any other topic with it? I htink i must do also a pressure test! Just to be sure!

Greetings

http://www.s2forum.com/forum/showthread.php?t=5893