[urq] Turbo/wastegate whistle: how and why?

Pasqualoni, James E james.pasqualoni at gs.com
Thu Dec 30 10:40:49 EST 2004

My sense is it's the wg diaphragm.  I recently installed a stiffer wg spring
w/ecu mod on my 86 5k tq, increasing boost from 11 to 15 psi, and
immediately, I heard the whistle while boost was building.  Opened up the
wg, pulled out the diaphragm, and it was slightly torn around a few of the
stud holes.  I haven't replaced it yet, as I'm not seeing any over-boost


-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On Behalf
Of DGraber460 at aol.com
Sent: Thursday, December 30, 2004 10:26 AM
To: urq at moregraphics.nl; urq at audifans.com
Subject: Re: [urq] Turbo/wastegate whistle: how and why?

In a message dated 12/29/2004 2:16:10 P.M. Mountain Standard Time,  
urq at moregraphics.nl writes:

Where  exactly does the loud whistling noise under boost come from? i.e. how

is it  technically possible for the turbo making such noise?

Could a shot WG  diaphragm causing this whistle? I know I only have 0,45 bar

/ 150 BHP and the  whistling noise is getting louder each month...

Also, could a wrong or  wrong adjusted WG spring cause the turbo to whistle?

Any  thoughts?



1986 GV (Swiss WR)  with 200K km original turbo/wastegate... 1985 CGT KV
1982 GL  DD

I've had my share of whistles from the "land of triple K", and found most
them usually in a hose or joint of some sort. My most frequent offender  has

been the rear section of the intake manifold to the head (3 times). I have  
not heard of a diaphragm whistling, but I suppose it might. Another usual  
suspect is the turbo to intake manifold hose. They are expensive, hard to
get,  and 
most have not been renewed in 20 years. Mine split just below the port  that

splits off to the IM spaghetti hose farm. It was totally undetectable
doing a pressure test.

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