I have guess I never noticed with the stock BPV. I'll have to check on that too at a later date. Right now I'm gonna try greasing it up.

I have the K&N SRI so I want to think it's normal, but a LARGE part of me wants to be safe and be sure.

**edit**

I think you might be right. As I test my newly lubed valve I notice that it still blows off smoothly but makes that barking noise still. It's like two Independent noises.

So K&N norm?

I guess I will have to put the stock one on and compare sounds.

 

I put my stock bypass valve in and I'm experiencing no surge like i did with the Forge VTA. So without a doubt this forge bypass valve is causing compressor surge. No compressor surge from any level of boost with stock bypass.

I am gonna attempt a refund.

A buddy of mine suggested I cut the spring to let it open more, but I'm not into doing that.

 

Mine makes a kind of barking noise at higher boost levels, usually at wot over 20 psi, but it doesn't sound like what you posted. Definitely doesn't happen at 10 psi.

 

Do you have the Forge VTA Bypass valve?

 

I'm wondering if the higher back pressure of the K04+ is causing my surge with this VTA BPV, because the local guy that has the exact same VTA Bypass valve is not having any issues anymore.

Would opening up my wastegate a little more help this problem? I really enjoy the sound of the VTA Bypass, but I won't put it on if it's causing surge.

 

Yeah I have the VTA forge with a maf relocate and hp tuned

 

thats surge, let me ask u a question, are u doing vacuum tank bypass? if so, thats ur problem

 

Seeing how I don't know what that is, I'm gonna have to say no I don't think I'm doing that vacuum tank bypass.

To illustrate how I had it installed, I put it on just like the stock bypass valve is installed. No other modifications were made.

 

try using pulling the line off the manifold and hooking bpv stright to manifold, if that fixes it, ill show u how to bypass vacuum tank

 

This slot opening isn't on the back side? Picture is of the normal BPV, can't seem to find any of the VTA version.

 

The VTA version doesn't look like that. I'm cleaning the VTA version and I'll make a video of it. One sec...

Everyone keeps thinking it's the same, but it's not.

It'll be good so people can see how it works too.

 

if its venting to atmohphere it wouldnt work like the recirculating one. the slots there to allow air back in as the piston moves.

 

My video is processing right now, apparently made the mistake of making it 1080p and it's gonna take 15 minutes to process.

I have it broken down and I reassemble it and it should give more savvy people an idea how it works such as yourself.

Like I said something is up with my particular set up because a local SS/TC owner (Leemanfor) is not getting any surge and apparently another person here isn't either.

The only difference I can make out is I'm using a K04+ (or WR-1). When I had the regular version of the Forge BPV on my stock turbo I used the yellow spring and no surge happened, but the moment I switched to the K04+ I started to get surge, then I switched to green and it went away, so without any real knowledge of the situation, I just assume that maybe this bypass valve is too much for my turbo (K04+). The yellow spring appeared to be too much for it as well... so I assumed anyway.

I'll have the video up within the hour for those interested

 

Here's the link to that video. It'll be up in a few minutes.

 

Ah! Thank you sir! That clears things up a bit.

 

No problem, sorry about the jumpiness of it, that's what I get for using 2 anti-shake 'enhancements' one on my mac and one via youtube. It looks kind of creepy.

 

dude my piston was really lubed up when i got it. had a bunch of red lube on it. It was still a bit hard to push up and down. so far no surge

 

Was there ever any outcome with this? I just installed my VTA Forge and I get some "flutter" noise. For me it happens more at lower boost, and actually even in vacuum if I let off anywhere from 10inHg - 0psi, then between 0psi - 10psi. On the boost side if I'm accelerating harder (boosting about 10psi or more) it doesnt do it. I'm still waiting for my updated Trifecta ECP tune, so I'm not sure if that could be causing it. I haven't changed springs, it came with the green one in it I believe. So what did you guys finally figure out? Green or yellow spring? I'm GMS1, K&N SRI, Catless DP, Trifecta, and the Forge VTA.

 

ok.

First off, I used the green spring for awhile but it wasn't holding boost well. I swapped to the Yellow spring and had flutter. I had to lube the piston up a bit, so i went and bought Mobil 1 lubricant and it helped a bit. However, with the yellow spring you will get flutter at around 10 psi.

I made a video and sent it to Forge and their Engineer replied telling me it was turbo flutter, and nothing to worry about. Even stock BPV cars have turbo flutter you just cant hear it well. He showed me a video of real "surge" which, was a video of a Skyline, and it didn't sound anything like surge. I actually like the flutter sound.

I have been running the yellow spring for 6 months and I have no problem. Holds 26 psi and I have no oil leaks from the turbo, checked the shaft last week when I was cleaning the intake and there is no shaft play

 

Turbo flutter can still decrease the life of the turbo, ur basically having ur turbo spin one way and then a rush of air coming back trying to force it to spin the other way. In the long run, that ain't good. And that's bs that the bpv has flutter it doesn't at all unless u boost up in a high gear and it doesn't have enough vac to open. Normal driving there is 0, in fact I think it stays open for to long, at least 2 seconds of blowoff and u can still hear a tapering off blowoff till u hit the gas and it closes.

 

good info. i'm thinking about picking this piece up soon.

 

This is false, it doesn't make the turbo blades spin backwards. the noise is the turbo blades chopping the air. the force required to stop and make the blades turn backwards would need to be considerable considering they are spinning extremely fast.

Flutter does not decrease the life of the turbo. Surge does.

I have ran this thing for almost 10 months with the flutter all the time and I checked my turbo about a month ago and everything is fine, it boots to 26 psi no problem and has no shaft play.

my buddies Saab 9-3 flutters with stock bpv, you can hear it now that he put an intake on it.

 

yea ive ran mine for about 5 months now and no problems here.