Re: FW: Older 5K Waste Gate Diaphragm fix/substitute

[rjandrew@post.cis.smu.edu (R Justin Andrews)]

Well when I talked to Rod and many others....
It was my undestanding that the 4 prong is a VDO OEM replacement...
The 3 prong is aftermarket and they die within a year....

HTH!
Rich Andrews
rjandrew@post.cis.smu.edu
> 
> ... as it appears that the sources for replacements are few, I thought I'd
> repost a message I got from the list and tucked away in my archives.  I've
> never experienced the condensate that the poster complains of, nor have I
> tried to do this myself ... I thought it might be interesting in the event
> that I ever lost a WG diaphragm ...
> 
> If anyone was interested I suppose they could contact the original poster to
> see if the thing is still working in his car as it is now almost a year
> later.  Frankly if I knew I could replace the diaphragm for next to nothing
> and have it last a year I think I'd do it ... it isn't _that_ difficult to
> disassemble the WG ...
> 
> HTH!
> Steve Buchholz
> San Jose, CA (USA)
> 
> ----------
> From:  superba [SMTP:superba@pacbell.net]
> <mailto:[SMTP:superba@pacbell.net]> 
> Sent:  Tuesday, May 19, 1998 9:35 AM
> To:  Quattro
> Subject:  Older 5K Waste Gate Diaphragm fix/substitute
> 
> Hi All,
> 
> I've already explained that I'm not a regular subscriber in an earlier
> email.
> Like many other turbo owners, my waste gate diaphragm deteriorated severely
> due to condensate collecting in the upper bell housing.  The last time I had
> it off, about 18 months ago, it looked so bad that I simply couldn't put it
> back.  So, I looked around for a substitute, even contacting Bendix Air
> Brake, trying to get some air brake diaphragm material.  It probably would
> have worked but I couldn't con anyone into giving me a scrap to try.  So, I
> took a piece of an inner tube(from an old truck tire), used the upper cover
> of the waste gate as a template, drew it out and cut a diaphragm out of the
> inner tube.  The only tricky part was to draw lines through the 6 mounting
> holes with a pencil and a straight edge, which established the center point
> and the placement of the mounting bolts.  I provided for some slack material
> for the flexing of the piston by extending the hole marks outward by about
> 1/4".  I used a leather hole punch to punch the center hole and the mounting
> bolt holes.
> When I installed it, I expected it to tear up, burn up, or just die a
> premature death.  I ran it for a while, opened it up and looked at it and it
> looked none the worse for the wear.  I tried several fixes for the
> condensate;  my 5K turbo came with the upper bell housing vented to the
> engine compartment which I thought to be causing the condensate.  I tried
> venting it to the turbo inlet, and later to the inlet of the air filter;
> neither of which reduced the condensate.  I also tried turbo feedback by
> venting the pressure from the large tube that contains the over pressure cut
> off switch(it grounds the fuel pump relay under normal usage).  Turbo boost
> feedback provides amazing boost and a real burst of power.  However, I
> wasn't too eager to exceed my BMEP or blow oil so I removed this after
> trying it for a short time.  I suppose that one could become accustomed to
> the extra boost and drive prudently and accordingly.
> On May 17, 1998, I opened up the waste gate to inspect the diaphragm
> expecting it to be in shreds and it seemed just as intact as it was when I
> installed it!!  Except that it literally contained about 8 ounces of
> condensate which ran out as I opened the housing.  That prompted me to
> remove the vent to the air inlet which had caused more, not less,
> condensate.
> However, my trial shows that almost anyone can replace their waste gate
> diaphragm with a little time and effort and a scrap of inner tube.
> Direct any questions to me at superba@pacbell.net
> <mailto:superba@pacbell.net> .
> Cheers!
> Jim Jordan
> MCSE, MCT, MCP+Internet
> 81 5K Turbo/290K
>