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Discussion Starter · #1 ·
hi guys,

i have a question for all you saab guru,s will a dump valve work on my 1995 9000 cse hpt AUTOMATIC. i am curious because i happen to have a rather nice bailey one doing nothing in my garage.
thanx
George :)
 
G

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Yep, auto's still have dump valve's (mine does certainly).

It's about two thirds of the way down the main air intake pipe. You can either fit a recirculating or an atmospheric, but recirc seems to be the choice for the 9000.

Here's my shiny Forge Dump Valve. Ooooo, see how it gleams! :cheesy:
 

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Your existing valve will be a recirculating type, which has 2 connections. The Forge ones can be recirculating, or atmospheric which only have one. If you go for an atmospheric one, you need to blank off the other pipe. You can either make/find something, or you can buy a special alloy plug, which I think Forge also make. Partsforsaabs.com sell them.

Other than that, it's a straight swap :)
 

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yes. you will fit the BOV in the aluminium intake pipe and the pipe beneath should be closed. btw I did the same with the stock BOV for a while just to make it louder :)

I would fit an atmospheric one as I believe that these are louder ;)
 

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Discussion Starter · #8 ·
well i fitted the bailey atmospheric dump valve as above with mixed results. when i rev quite high in neutral gear it makes the nice wooshing sound but when driving on the road the valve is opening when the revs pick up and stays open for a long time..... until i back off the revs it seems. i,m no expert but isn,t this kind of back to front i thought the valve was mean,t to dump pressure only when the gears changed or the revs backed off. is the little pipe attached to the dump valve supposed to be sucking all the time mine is although it isn,t that strong on idling. i,m getting confused my head hurts can one of you saabaholics tell me what,s wrong if anything.
thanx in anticipation
George
 

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geo9000cseturbo said:
well i fitted the bailey atmospheric dump valve as above with mixed results. when i rev quite high in neutral gear it makes the nice wooshing sound but when driving on the road the valve is opening when the revs pick up and stays open for a long time..... until i back off the revs it seems. i,m no expert but isn,t this kind of back to front i thought the valve was mean,t to dump pressure only when the gears changed or the revs backed off. is the little pipe attached to the dump valve supposed to be sucking all the time mine is although it isn,t that strong on idling. i,m getting confused my head hurts can one of you saabaholics tell me what,s wrong if anything.
thanx in anticipation
George
My guess is that the spring inside your valve isn't stong enough to hold the boost you're making. Is it adjustable? If it is, adjust it.

BPVs/BOVs are designed to open when the pressure in the intake manifold is less than the pressure between the turbo and the throttle. That vacuum hose that goes from the valve to the intake manifold is what opens and closes the valve: less pressure on the throttle side and more pressure on the intake side just pushes the valve open until pressure is equalized. A spring inside the valve determines how much pressure the valve can hold, and if you exceed that, the pressure from the intake alone can overcome the spring and force it open. It sounds like that is what is happening with your car.
 

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Discussion Starter · #10 ·
thanx for that

i don,t see any adjustment on the valve so i guess i,ll have to put the stock one back in. so do you think that there is not actually a problem with the turbo etc ?
 
G

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Doesn't sound like it. If there is whooshing at all then the turbo will be boosting.

Best to buy a dump valve designed for a Saab - not pricey, about £85 for a Forge atmospheric and £95 for a Forge recirculating.

BTW, the atmospheric may cause momentary overfuelling but it does make more noise. :cheesy:
 

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if you buy an atmos' dump valve, make sure you buy a twin piston type, the single piston ones are no where near as good
 
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