eman930

So can anyone tell me what the advantage of changing the spring in your bypass valve is??? I have the Lindsey non Adjustable bypass valve, I'm running 16psi, Would getting a adjustable bypass valve have any benefit

eman930

Anyone??

Scott H

Short answer: if your diverter valve is working fine (from your sig. it's the billet DV from LR?), then you'll gain nothing. If your DV is staying closed when you're on boost then you're fine.

eman930

Ok cool thanks, Yeah I think it's staying closed, I just wasn't sure how much boost you can run untill it starts getting forced open

Scott H

You can adjust yours with the following kit: http://www.forgemotorsport.com/conte...roduct=FMDVTUN

Most billet Porsche/VW DVs are made using Forge internal components/dimensions. But, like I said before, if yours is functioning fine you will notice no difference.

CurtP

Most people in this forum install their aftermarket bypass valve backwards, so it really doesn't matter what spring is in it.

TurboTommy

It doesn't matter which way you install the recirculation valve, but the opening characteristics will always be governed by the spring tension.
The thing is, though, that the spring strength (or preload) does not have any influence at full boost, but it does affect performance at throttle lift, and transient boost response, especially in and out of part throttle.

CurtP

How do you figure? The pressure side should be at the bottom of the piston so if vacuum line ever becomes detached/damaged/plugged, it will still open the valve during a pressure surge. If you install the valve backwards, as most do, the pressure surge will be on the side of the piston and it will not open.

TurboTommy

I've had 3 different recirc valves, and even the stock one. They were all in such a way that pressure on the surface areas will open the valve no matter which way you install it. Look closely.
That's what I've seen so far.

CurtP

There's no way for a valve to open when the pressure is being applied to the wrong side of the valve. More than likely what you've seen is the operation of the valve with the reference line in place.

TurboTommy

Did you actually look at a valve before you posted this?
Like I said, look closely
Which valve do you have?

CurtP

I'm starting to wonder if you ever have. Look again. Then look again. Then have someone explain it to you. Then have someone demonstrate it for you. Then walk away saying you're still right because you don't understand basic physics. On one side of the bypass you'll see the face of the piston which you can depress with your finger. That goes on the pressure side. Look through the other side of the bypass valve and you'll see a hole and the side of the piston. Put pressure on that side and nothing happens.

I have a Turbosmart Kompact which is very similar to all the other piston style bypass valves (including the Forge I replaced that came on my car). They even show how it is supposed to be installed compared to a standard Bosch-style diaphragm valve:
http://www.turbosmartusa.com/wp-cont...t_PlumBack.pdf

Even Wiki shows the orientation of the bypass piston to the TB: http://en.wikipedia.org/wiki/Blowoff_valve

I know, you're still right and I really don't care. But I wanted to at least post something before you continue to spew more misinformation to others. Since everyone else does the same thing, I guess that makes it right!

C ANDERSON

CurtP ,
Thanks for the wiki link to this . I was in the process of drawing it out to show the proper way.
I see more put in the wrong way than correct , even on some other wise well prepared cars. This ain't rocket science.

TurboTommy

If you put pressure on that side it will open!

If you look closely into the opening of "the side of the piston" you'll see it's tapered down and at the other end there's a ridge. This ridge has the same surface area as the "face" of the piston; and if the boost were to enter that side, it will flow around the taper, put pressure on that ridge, open, and flow out past the "face" of the valve.

Call LR; they sell the forge you had, and they'll tell ya: "yep, you can install it either way"

Lastly, in the turbosmart link you posted along, where it compares the two valves, it clearly shows where the boost can enter the "side" of the bosch valve (the side you said should not see boost).
You look like an ***.

You can take a couple of days to digest this, and if you have any integrity you'll post back with apologies for posting mis-information.

CurtP

Please, go pull your bypass valve off, take pictures proving your point. Here's Forge's IPB: http://www.forgemotorsport.com/valve_service.pdf
Go to bottom of the document where it shows how to do the leak test, only put your pen in the side port and push. What happens?