I just installed the Forge VTA BPV and was wondering what spring I should use? currently a green one and they sent me a yellow one, the green one is in there but it seems to take a second to blow off and I get minor compressor surge. I love the sound but the compressor surge is no bueno

 

Well I tried the yellow one, no better.

 

I've read something about people installing the spring upside down accidentally ? not sure if thats the case or how that applies, just saw it somewhere so please dont qoute me on this lol

 

the opening of the piston should be pointing to the ground ive heard, mine is on its way ill let you know if no one has yet.

 

hmm ok. mine is facing up. i will have to rotate it

 

Im using the green spring tho im about to try the yellow on my forge vta

 

You have to use green on K04+ just a FYI if you go that route.

Anyway, can you make a video. I'd love to hear it.

 

will do mike.

 

Also FYI there is no "opening!" It opens all around the top. This bypass valve you can install anyway you want, since its VTA the openings are in a circle on top of the bypass.

My guess is the spring is too strong even the green. I don't know though.

 

the bottom opening where the piston opens and closes should still be the same, that's the one that matters, that needs to be facing down.

 

negative. this is different than the other Forge. There is no notch or anything to identify which way it went.

I resolved this issue by unkinking some vacuum lines. I dont get anymore surge

 

really? huh, guess I'm wrong again.

 

I've been talking with Angel at Forge about this issue. I'm gonna see what the issue is.

Yeah the Forge VTA doesn't have the same mold (if thats the right word) as the regular bypass valve.

 

use the softer spring...

if you compressor surge means your bov is not opening all the way and some of the air is going back

 

The thing that is frustrating is it's the green spring being used.

 

Right, but the softest spring we can use is the Green one and its still surging.

 

hmm... maybe the bpv is not openning all the way?

try pushing it with your hand open. see why it's so hard to open... should not be that hard to open. should be a firm squeeze to open the bov. not sure how the forge vta bpv works tho...

 

I was thinking about re-greasing the piston to see if that is the problem but so far I havent had any surge

 

right on. if it's a piston you should try and be able to push the piston open. that's what i do for fun with the cobalt when the car is off lol... it's under vaccum when i turn the car off. and sometimes i like to open the piston and feel the air come out. lol...

 

I'm getting it, now. Super frustrating. Mine however only happens at 10psi or higher. Anything under that it's a smooth psssssss. Nice sound.

Anyway, the openings on the VTA version is on top as you can see in the image. Everything under the flange piece is solid. There's no opening underneath the flange piece, or the "cylinder" piece. Well minus the very very bottom of it.

 

did you check to see if your piston is greased?

 

Just as an fyi the spring cannot be installed upside down. Its are compression style spring and there is no up or down. The only different would be a right or left hand cut which on compression springs doesn't matter. My guess is the spring is too strong or the pistons are not greased well and should be lubed

The only way the spring would be upside down is if the diameter on one end is different from the other but at that rate usually the seats will only fit the side. Being that guys can flip them around means there's no up or down.

 

I noticed when I had it off that it was sort of hard to push the piston. it had some grease but not a lot. I need to re-grease mine

 

Okay I'll lube it up. The only greese I have is Valvoline Synthetic Greese, I did lube up the o-rings though.

Anyway here's my surge issue. What's weird is it wasn't this way a couple days ago. It seem to have developed this. Perhaps it is a lube issue.

**Edit**

The surge doesn't happen under 5 PSI, so when I drive normally, I don't hear the surge. It's a nice clean blow off.

 

Mine made the same noise as yours after 16lbs of boost. It's normal - you can even hear the turbo make that same noise if you have a K&N intake and the stock BPV. You have to know what you're listening for though.