re: To bypass, or not to bypass...

[Phil Rose <pjrose@servtech.com>]

>Date: Sun, 26 Apr 1998 11:50:15 -0600
>From: "Frank Amoroso" <famoroso@sprintmail.com>
>Subject: To bypass, or not to bypass...
>
>A friend of mine gave me a sport quattro bypass valve to use in my '93 S4 w/
>62,500 miles.
>So yesterday I pulled out the stock valve (Bosch 0 280 142 108, VW/Audi
>034145710A) and, guess what, the rubber membrane in the valve was blown to
>bits. About 60% of it is missing. Has this happened to anyone? I'm assuming
>the rubber bits are stuck in the intercooler somewhere or have been
>aspirated through the motor.
>
>The valve I put in is Bosch 0 280 142 102 (no VW/Audi part #). I've yet to
>test drive.
>
>I was having an intermittent whistle on boost and I am thinking this is what
>may have caused it?
>
>Frank--
>- -----Original Message-----
>From: Phil Rose <pjrose@servtech.com>
>To: quattro@coimbra.ans.net <quattro@coimbra.ans.net>
>Date: Friday, April 24, 1998 7:49 PM
>Subject: bypass, shmypass: cut 'em off at the pass
>
>
>>I had become convinced that the turbo's bypass valve on my '91 200q was
>>faulty--based on the car's running and many posts from the qlist (thanks
>>Wolff and others). Now, to get a replacement valve.
>>

The valve I replaced on my '91 200q wasn't visibly messed up, but it
couldn't hold _any_ vacuum from the control-tube port. After I replaced the
valve, the shifting became much smoother (with less turbo lag), and I
noticed that there was no longer a hissing noise (not a whistle) that I
previously could hear from the right side of the engine each time I let up
on the throttle during upshifts. I guess this was from the leaky bypass
valve.

Phil Rose		Rochester, NY
'89 100
'91 200q		pjrose@servtech.com