Re: Pop off - defined

[PDQSHIP@aol.com]

In a message dated 96-12-06 03:53:10 EST, you write:

<< Subj:	Pop off??
 Date:	96-12-06 03:53:10 EST
 From:	cjohansen@lts.mil.no (colin marius johansen)
 Sender:	owner-quattro@coimbra.ans.net
 Reply-to:	cjohansen@lts.mil.no
 To:	Quattro@coimbra.ans.net (quattro@coimbra.ans.net.)
 
 I dont know what you all mean by Pop off valve, but I have mounted a
 "Pop off valve "(I dont have another name fore if) on my car.
 It is placed between the intercooler and the inletmanifold.When you let
 go off the throttel the turbo boost has no where to go.The valve opens
 and the turbo boost will go out in open air, or to the airfilter.
 This valve helps the turbo to run light, and reduses turbo wear.
 If the turboo boost is high enough,will the  valve made by Bosch make
 some ratteling sound.
  >>
That is a bypass valve whether bypassing to atmo or usually back into the
inlet side fo the turbo...   It is a pretty simple valve, shuts on boost
opens on vacuum...  A pop off valve, more defines the INDY max boost valve
that sits on the intake manifold and just pops when a boost level is
exceeded, no vacuum associated with it, it is all spring......   A bypass
valve allows the turbo to freewheel, reducing wear might be pretty liberal
use of the word, maybe on the stage II folks from IA...  MOST of Ned's stage
II boxes run over 20psi (in fact every one I've seen) and that should get you
to buy a bypass valve, cuz the stall on the turbo outlet without it can be
catastrophic...  Usually the IC/IC hose takes the brunt when no valve
installed....  Venting to atmosphere is not the suggested route, take the
time to send that "metered" air back into the inlet of the turbine....

HTH

Scott