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Euro-Tuner
03-24-2007, 04:42 PM
can anyone tell me what color spring I should be using in my forge 007 DV...I searched and didnt find anything here or on the Forge website. I am currently running 20psi on stock turbo. I am under the impression that I should be using a stiffer spring, but I need to check if its holding boost or not (wont be able to drive my car till tomorrow...) thanks in advance!![up]

bOOOOstedAudi
03-24-2007, 05:27 PM
mines same color as the dv, chromish

Euro-Tuner
03-24-2007, 05:56 PM
hmmm...they come with red, blue, yellow, and green. in the order or strongest to weakest...not sure whats in mine right now, didnt check, Im pretty sure it comes with the green one installed....

fred2ka4
03-24-2007, 07:21 PM
hmmm...they come with red, blue, yellow, and green. in the order or strongest to weakest...not sure whats in mine right now, didnt check, Im pretty sure it comes with the green one installed....

When I had my 007 Forge DV installed in my car, I was running 22lbs of boost on an APR stage III kit with all the supporting mods and the spring I had installed was blue and it worked just fine.

Hope that helps.

mike-2ptzero
03-24-2007, 07:30 PM
hmmm...they come with red, blue, yellow, and green. in the order or strongest to weakest...not sure whats in mine right now, didnt check, Im pretty sure it comes with the green one installed....

The spring tension only helps to over come any pressure drops, how quickly the valve opens and closes. The spring has nothing to do with how much boost the valve will hold since that is the job of the pressure in the vac line that is connected to the intake manifold.

Now if you were running the valve as a BOV the spring tension would have more effect since the BOV needs to stay closed till high vac(higher then idle vacuum).


BTW just a note from the Forge web site.

Please note - fitting a stronger spring into a valve will not increase boost pressure unless existing pressure is being lost. Failure to allow the valve to operate by installing a spring which is to strong may cause damage to the turbocharger.

Please note - the red coded springs should not be installed in the DVR or DV007 diaphragm valves

fred2ka4
03-24-2007, 08:35 PM
The spring tension only helps to over come any pressure drops, how quickly the valve opens and closes. The spring has nothing to do with how much boost the valve will hold since that is the job of the pressure in the vac line that is connected to the intake manifold.

Now if you were running the valve as a BOV the spring tension would have more effect since the BOV needs to stay closed till high vac(higher then idle vacuum).


BTW just a note from the Forge web site.

Please note - fitting a stronger spring into a valve will not increase boost pressure unless existing pressure is being lost. Failure to allow the valve to operate by installing a spring which is to strong may cause damage to the turbocharger.

Please note - the red coded springs should not be installed in the DVR or DV007 diaphragm valves

Mike to the rescue ......... [:D]

Mine was installed when I bought the car and the only reason I switched it out was because I thought I was having problems with my DV not releasing pressure quick enough and causing an overboost condition.

Euro-Tuner
03-25-2007, 08:43 AM
fitting a stronger spring into a valve will not increase boost pressure unless existing pressure is being lost.


thats what I read too, so I was hoping I wasnt losing pressure....just looking for someone who went through the same thing I am in, wondering what they did, I am under the impression that I should be using the yellow spring, but I dont want to hurt something, not really sure how to tell, but I'll drive a lot today and keep a close eye on my boost, and let you guys know what I find out![up]

mike-2ptzero
03-25-2007, 09:55 AM
thats what I read too, so I was hoping I wasnt losing pressure....just looking for someone who went through the same thing I am in, wondering what they did, I am under the impression that I should be using the yellow spring, but I dont want to hurt something, not really sure how to tell, but I'll drive a lot today and keep a close eye on my boost, and let you guys know what I find out![up]

Just make sure you listen for any compressor surge when you increase the spring tension by changing springs.

T28_A4
03-25-2007, 11:45 AM
you want to be running the yellow spring...

Euro-Tuner
03-25-2007, 04:31 PM
Im gonna run the yellow spring and possibly one or two spacers...

this (http://forgemotorsport.com/content.asp?inc=product&cat=0007&product=FMDVTUN) helps also...

Pat@Forge
03-28-2007, 08:53 AM
It is possible to have too weak of a spring, here is an excerpt of a post I made on another forum explaining why.

"Is it just me or does his math seem off?
A 3" diaphragm, which I assume would be a circle, would have an area of 7.06. Or is my math off? Area of a circle is radius squared times pi, is it not? So... 1.5 x 1.5 x 3.14159 = 7.069.
And the 1.25 circle would be about what he said.
This strengthens his argument.

Of course all that math is irrelevant if it doesn't take into account all of the variables. In this case mainly pressure drop and latency.
Forgive my grammar from here on out as I plan on using sentence fragments

*WOT, the chargepipes are pressurized beneath the BOV/DV

*x number of milliseconds later the intake is pressurized

*during this gap the top of the valve will be under vac and the bottom is pressurized

*if the spring tension is not great enough the valve can open, even if only a few mm

*at this point the surface area that the charge air is acting against will be THE SAME as the top of the piston/diaphragm (or at least in every valve that I have seen)

*now you have a leak at WOT

*And I didn't even take into account the drop in pressure that the top of the valve will see

The pressures that you see, the spring tensions, etc. none of these variables are likely to be constant or linear. The valve may well reach equilibrium with the sealing surface open a few millimeters, allowing a small amount of boost to escape/recirc.


And then we have the variable of DESIGN. What if the surface area of the intake side of the valve and the charge-air side are nearly the same? Will the pressure drop alone be enough to overcome spring tension? What if the valve has a side entry for the charge-air? The surface area on the underside of the piston could be greater than the surface area available for the vac/boost reference to act upon, and spring tension will be the only thing keeping it closed.

A negative cannot be proved, you can only prove that the opposite is possible."