[studio54]

Hello,

i read a lot of threads where we talked about which spring using for the Forge DVs, and the conclusion was "use the yellow spring" if you are tuned.

It was said like :

Green - 5-15 PSI
Yellow - 15-23 PSI
Blue - 23-30 PSI
Red - 30 + PSI

It was mostly understood like, let's say if you use the green ones, if your tune push more than 15 psi it will not hold the pressure. While it's not really like that in reality.

If you hook the Forge DVs in the orientation like this picture :



(i installed them in this position)

I believe that it's doesn't really matter. Because the pressure boost + the spring force works together. I mean spring force + boost force (through the vacuum hose) hold the valve closed when WOTING, so no reason to leak.

So why not use the green spring with anytune since it will release the pressure easier and make less stress to the turbos in any situation ? It will not create any boost leak and hissing on WOT since the piston inside the DV will push closed.

It may close faster on WOT, but I don't believe that it will make much difference (or perceptible difference/lag) in spool time but i am possibly maybe wrong?

I probably ask that cause i am paranoid since i had a blown turbo lately, and i want to take care of them as much as i can ($$$$). I will probably swap to green to test.

Some reading :

https://www.e90post.com/forums/showp...6&postcount=44

What do you think ?

[Bimmer_Bro]

Originally Posted by studio54

Hello,

i read a lot of threads where we talked about which spring using for the Forge DVs, and the conclusion was "use the yellow spring" if you are tuned.

It was said like :

Green - 5-15 PSI
Yellow - 15-23 PSI
Blue - 23-30 PSI
Red - 30 + PSI

It was mostly understood like, let's say if you use the green ones, if your tune push more than 15 psi it will not hold the pressure. While it's not really like that in reality.

If you hook the Forge DVs in the orientation like this picture :



(i installed them in this position)

I believe that it's doesn't really matter. Because the pressure boost + the spring force works together. I mean spring force + boost force (through the vacuum hose) hold the valve closed when WOTING, so no reason to leak.

So why not use the green spring with anytune since it will release the pressure easier and make less stress to the turbos in any situation ? It will not create any boost leak and hissing on WOT since the piston inside the DV will push closed.

It may close faster on WOT, but I don't believe that it will make much difference (or perceptible difference/lag) in spool time but i am possibly maybe wrong?

I probably ask that cause i am paranoid since i had a blown turbo lately, and i want to take care of them as much as i can ($$$$). I will probably swap to green to test.

Some reading :

https://www.e90post.com/forums/showp...6&postcount=44

What do you think ?

Using yellow or green is going to make zero difference to the life of your turbos or how fast the valves open. I do see your thinking since the pistons would be horizontal in that picture, you would not have boost pressing against the bottom of the piston.
I have always ran yellow and had zero issues. I think you are over thinking things. Its only slightly stiffer so I would use the one rated for your boost levels. Regardless of the spring weight it opens the same.
I do remember users using green and having them leak before they switched to yellow. Not sure the logic on that but I do remember an old thread.

[studio54]

Originally Posted by Bimmer_Bro

Using yellow or green is going to make zero difference to the life of your turbos or how fast the valves open. I do see your thinking since the pistons would be horizontal in that picture, you would not have boost pressing against the bottom of the piston.
I have always ran yellow and had zero issues. I think you are over thinking things. Its only slightly stiffer so I would use the one rated for your boost levels. Regardless of the spring weight it opens the same.
I do remember users using green and having them leak before they switched to yellow. Not sure the logic on that but I do remember an old thread.

Thank you for your answer.

Yep i am always overthinking

That said, i don't understand how it can leak green or yellow since the boost push them closed ?

[Bimmer_Bro]

Originally Posted by studio54

Thank you for your answer.

Yep i am always overthinking

That said, i don't understand how it can leak green or yellow since the boost push them closed ?

It's a good question, but I am not sure either. I figured there must be a reason since they come with different springs.
Experiment and report back. I also have my green springs somewhere.

[studio54]

Originally Posted by Bimmer_Bro

It's a good question, but I am not sure either. I figured there must be a reason since they come with different springs.
Experiment and report back. I also have my green springs somewhere.

Yep me too, my green springs are in a box somewhere.

I understand spring matters if you installed the Forge DVs with spring force facing the chargepipe two pipes (you can install Forge two ways), if you install them the other way (like we do) with spring force working with the boost, i am pretty unsure if it will really close faster (something you can feel in throttle response), but they will release faster making less stress to turbos for sure when boost is inside the chargepipe and you closed the throttle.

Honnestly, in theory, i don't why it would be better to run yellow instead of green.

I may try, and if i do, i will report here if i feel a difference.