BOV spring upgrade
Senior Member
Joined: 09-23-08
Posts: 6,621
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From: Raleigh, NC
This spring, opens and closes the bypass valve correct????
So it can be bleeding boost off, because of a weak spring, it's a known problem. His car does bleed some boost off... I have the logs to prove it!
Senior Member
Joined: 05-14-08
Posts: 1,023
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From: around the world
But post the logs anyway and show me where its bleeding off boost.
New Member
Joined: 03-12-07
Posts: 63
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From: new jersey
http://www.youtube.com/watch?v=98OWFPayADk hope you guys like
Senior Member
Joined: 07-25-08
Posts: 12,450
Likes: 6
From: Florida
I'm definately getting mine soon, along with the AEM intake. 
To you all that have installed the spring already that are tuned have you noticed an increase in the response of the turbo after lifting then applying full throttle again. Looking at how thin the stock spring is it looks like it would not close the BPV as near as quickly, and I bet you the stock piece will be toast after 20K miles of Hard driving with higher than stock boost levels.
To you all that have installed the spring already that are tuned have you noticed an increase in the response of the turbo after lifting then applying full throttle again. Looking at how thin the stock spring is it looks like it would not close the BPV as near as quickly, and I bet you the stock piece will be toast after 20K miles of Hard driving with higher than stock boost levels.
Senior Member
Joined: 07-25-08
Posts: 12,450
Likes: 6
From: Florida
I finally installed this on my car today. It is definetly worth $10 and sounds amazing. Install took me about 15-20mins. I took out the whole intake to make it easier to get to the 10mm bolts.
Oh and how is this not a how to yet????
Oh and how is this not a how to yet????
Last edited by Black08SSTC; Jan 8, 2009 at 12:44 PM. Reason: Automerged Doublepost
Member
Joined: 07-09-08
Posts: 356
Likes: 0
From: Farmington, MI
I think I get it...
Engine vacuum over powers the spring to allow the extra air from the turbo to bypass going into the engine in scenarios where there's a restriction (i.e. throttle body closes when turbo is spooled up). Looking at the picture above, it appears the hose connected to the tan/plastic cover is the vacuum source. During normal driving and operation (when a vacuum is present), this vacuum holds the black plunger/valve open. When you hit the gas and the turbo spools up, the vacuum turns into boost. Keep in mind, boost is on both sides of the plunger now. The hose providing the vacuum is now pushing on the plunger along with the spring. However, the other side of the plunger is pressurized as well. Since the tuned applications are pushing another 7~8psi over the factory setup, it is possible that the spring has become too weak to handle the task of keeping the plunger shut.
The side effect of a stronger spring will alter the way boost is built in the mid-range. As engine vacuum decreases, the stronger spring will close the plunger a little sooner than the stock spring. In theory (my theory that is), upgrading to a stronger spring may affect the highway manners of the car when vacuum is moderately low (i.e. on slight inclines, normal passing, etc.). I believe the transition between boost and vacuum will be more pronounced - making it more difficult to stay out of boost in the situations I previously mentioned, which would in effect potentially have a negative effect on MPG's.
If you're going to do it yourself (with a washer or different spring), keep in mind the warning of not going to far. Too much spring pressure will not allow the plunger to open. That will put undo stress on the turbo (boost pressure backup in the intake) and wear it out faster. Hopefully, the people selling this spring have put enough R&D and or thought into the spring they're selling to make sure that doesn't happen.
Engine vacuum over powers the spring to allow the extra air from the turbo to bypass going into the engine in scenarios where there's a restriction (i.e. throttle body closes when turbo is spooled up). Looking at the picture above, it appears the hose connected to the tan/plastic cover is the vacuum source. During normal driving and operation (when a vacuum is present), this vacuum holds the black plunger/valve open. When you hit the gas and the turbo spools up, the vacuum turns into boost. Keep in mind, boost is on both sides of the plunger now. The hose providing the vacuum is now pushing on the plunger along with the spring. However, the other side of the plunger is pressurized as well. Since the tuned applications are pushing another 7~8psi over the factory setup, it is possible that the spring has become too weak to handle the task of keeping the plunger shut.
The side effect of a stronger spring will alter the way boost is built in the mid-range. As engine vacuum decreases, the stronger spring will close the plunger a little sooner than the stock spring. In theory (my theory that is), upgrading to a stronger spring may affect the highway manners of the car when vacuum is moderately low (i.e. on slight inclines, normal passing, etc.). I believe the transition between boost and vacuum will be more pronounced - making it more difficult to stay out of boost in the situations I previously mentioned, which would in effect potentially have a negative effect on MPG's.
If you're going to do it yourself (with a washer or different spring), keep in mind the warning of not going to far. Too much spring pressure will not allow the plunger to open. That will put undo stress on the turbo (boost pressure backup in the intake) and wear it out faster. Hopefully, the people selling this spring have put enough R&D and or thought into the spring they're selling to make sure that doesn't happen.