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Hello All,
I am just switched to the Forge unit from the stock Bosch one. My car seems to be holding boost better and running well. I wonder if the correct spring is being used though. I am aware that the green spring that it comes installed with is the recommended spring. Some use spacers and some run the yellow spring.

I wonder if my car is holding onto boost too long or something. It seems that when letting off the throttle quickly the engine maintains the speed/revolution a bit longer than before. Almost like the car is "overboosting" or something. Basically, the revs *might* not be dropping as fast anymore.

How does one tell if the spring is too strong or too weak.
Sounds?
Open SID readings?

My Forge unit is installed in the "reversed" position as described in various places such as, http://www.econmancer.com/?p=75.

*****Also****
When installing this, a spot welded tab on the metal pipe that connects to the diverter valve broke off. This is the only metal pipe, it is on the left of the diverter valve and runs down towards the exhaust manifold/heat shield. The tab was on a washer/ringe and helped to keep this metal pipe from rotating. I am not sure if this is a problem that is worth fixing. Car runs fine and the metal pipe seems to be just as "sealed" up as before. I don't know, any suggestions?
 

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subscribed. I have the same valve and would like to know what the different springs mean. Not trying to hijack though, just along for the ride ;ol;
 

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The stronger the spring, the more resistant it is to being pushed open by higher boost pressure, rather than the ecu opening the valve. So, if you're running a stage 3 map, with higher than standard boost, its possible that the boost pressure will push the valve open at max boost, losing boost pressure. Fitting a stronger spring will stop this happening. The green spring offers the same pressure resistance as the standard valve, yellow, red etc will hold higher boost. Gives the relevent pressures on the Forge site. ;ol;
 

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i think the "spot weld" you are referring to was the bolt that hold the metal pipe from the BPV to the cobra pipe

i dont think that the boost pressure can push the spring open. The vacuum line connected to the BPV sees boost pressure also, therefore there is equal boost pressure pushing on both sides of the spring so it shouldnt move until the throttle is closed
 

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i dont think that the boost pressure can push the spring open. The vacuum line connected to the BPV sees boost pressure also, therefore there is equal boost pressure pushing on both sides of the spring so it shouldnt move until the throttle is closed
I'm no expert but I'd tend to agree with Civicbeater here.

This may also be a good time to suggest the "vacuum hose" mod if you haven't already done it!;ol; IMHO I think it provides SLIGHTLY better response
 

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The stronger the spring, the more resistant it is to being pushed open by higher boost pressure, rather than the ecu opening the valve. So, if you're running a stage 3 map, with higher than standard boost, its possible that the boost pressure will push the valve open at max boost, losing boost pressure. Fitting a stronger spring will stop this happening. The green spring offers the same pressure resistance as the standard valve, yellow, red etc will hold higher boost. Gives the relevent pressures on the Forge site. ;ol;

I started by trying to hijack this thread, but due to no response, I've edited this post to link to my question directly:

http://www.saabcentral.com/forums/showthread.php?t=247939
 
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