Re: Pop off (turbo bypass )valve

[PDQSHIP@aol.com]

In a message dated 96-12-04 14:07:45 EST, you write:

<< I wanted to know.....The "pop off" valves that Indy and F1 cars use...are
they
 pretty much the same thing that Audi uses? Why is it that only Audi uses
this
 design which is better (and quieter..ever hear a wastegate flap rattle?)
What
 are the symptoms of it going on it's way out? Any noises or
 sounds?.....Thanks.....Steve
 
  >>
No the pop off valve indy cars use is to regulate maximum boost and either
allows boost or "pops it off" at a specific psi and is before the valves
(between turbo and head), not at all the same as a Wastegate that controls
boost via a bypass of the exhaust gasses to the exhaust vs the turbine of the
turbocharger....  Wastegate flap rattle is common, wastegates tend to work or
not, it is a dumb device, the only thing that an audi wastegate does
sometimes is rip the wg diaphram...   The symptom is computer shutdown after
max boost level achieved, since a ripped diaphram will allow max computer
boost on most turbo cars.....  That would be a bad thing....

HTH
]
Scott