bypass valve

[QSHIPQ at aol.com]

Joshua:
Common mistake is the mis install of the Bosch bypass valve.  The boost inlet 
should be 90 degrees to the vacuum nipple, IOW, the piston itself closes 
against vacuum, not pressure.  If you hook it up the other way around the 
valve will blow open between 6 and 9psi (depending on turbo/engine).  That 
said, I cked the Dahlback site, and honestly couldn't tell whether they were 
correctly hooked up, but liked the dual application, something I've been 
advocating for quite a few years here.  

Scott Justusson
>In a message dated Thu, 8 Feb 2001  6:24:35 PM Eastern Standard 
>Time, Joshua Van Tol <josh at spiny.com> writes:
><<
>Nope, they're in the right way. The inlet is in line with the 
>vaccuum hose connection, and the outlet is at 90 degrees to the 
>other two. If they were in wrong, they'd never open.
>  >>
>
>    You are incorrect in your description, the inlet/boost side 
>should be perpendicular to the vacuum inlet as in the factory 
>installation.  The way Dahlback has installed them is backwards, and 
>will cause them to leak under higher boost levels.  The only thing 
>keeping them closed is about a 5 lb spring and intake manifold boost 
>thru a 3mm vacuum hose, not much.
>Javad

>>Okay, I need to get one of these valves in my hand before I can say 
>>for sure whether I agree with you. I thought I remembered how these 
>>worked from Saab applications, but maybe I misremember.
-- 
>>Joshua Van Tol -- josh at spiny.com