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Discussion Starter · #1 ·
Today I drove 30 miles with the yellow spring. I noticed the woosh noise was less than with the green spring. I feel like the car has a slight hesitation to it now. I also believe I heard air escaping through the air box (but not audible flutter noise).

I called Forge and spoke to a gentleman who informed me of the following:

They do not have any specific pressure ratings for the springs. These type of replacement BOV/BPV are common among many cars so it isn't a specific to Cruze application. But, one of the two springs should work for any application.

Green Spring:
Meant for stock boost levels and should handle any stock levels without problems. Potential issues: pressures are too great and the BOV/BPV will leak, causing a drop in boost.

Yellow Spring:
Meant for tuned applications running beyond stock boost levels. Potential issues: Spring is too stiff and has a delay, causing pressure to go back into the turbo.

I explained that the stock Cruze gets up to 16psi and I have a tuned application @ 22psi. He said then the yellow spring would be what to use. He asked me if I noticed a delay in the yellow spring and I said yes, but I also (I need to confirm) saw max 20 psi on the green spring.

He asked if the vacuum line was attached to the manifold directly or if it went to a solenoid. I did not know. I believe it goes to a solenoid (PLEASE CONFIRM THIS). He said if that's the case then it may be beneficial to tap directly into a vacuum line to remove that delay. Of course, he said he can't guarantee that information.

I'm going to swap the green spring back in and do some more driving.

Can someone confirm if tapping into a vac line directly would cause any issues with the car.
 

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Wow thanks for the info. I too notice hesitation and sometimes I hear the bov open and shut very quickly after without a long whoosh(very very short.) I installed the yellow spring to begin with, never tried the green. But my boost usually goes to 25psi.
 

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Discussion Starter · #3 ·
Confirmed that with the green spring you're only going to see 19-20psi. However, the green spring gives more of the sound and more often especially under light throttle (so you can rev it at the light and get a woosh).

I'm conflicted as I want my full potential, but I also want the sound and no lag. I think we need another spring that's right in between these two, unless of course we can tap off the vacuum line which I think I'll try next. If that works then the yellow spring is the way to go for tunes.
 
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just curious about the valve- I believe one of the vendors stated there was no performance benefit, it was simply for the noise. But we are seeing 1 spring reduces max boost & the other introduces lag. Hmmm. Will the noise induce fear in the heart of a mini cooper- S owner? ;)
Hope you get less lag tapping into the vacuum line directly!
 

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I can only read so much lol.Got to call it the way it is ! Those things are junk by the sounds of it.But i guess if you like that kind of noise it may be worth it.It just seems like more trouble than its worth.If there was some HP involved it would make some sense
 

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There's not going to be a performance gain by switching BPV/BOV. They both perform the same function, releasing pressures at the same level. Springs may adjust pressures slightly. It's a sound modification really, and I'm waiting for an adapter to be created so we can run the name brand BOV's. Then styles of noises could be chosen.
 

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Discussion Starter · #7 ·
I can only read so much lol.Got to call it the way it is ! Those things are junk by the sounds of it.But i guess if you like that kind of noise it may be worth it.It just seems like more trouble than its worth.If there was some HP involved it would make some sense
I disagree. The more I drive it the more I like it. Tonight on the freeway and around town the car felt very strong off the line (I put green spring back in), after each shift and well into the boost. I've noticed the boost comes on much faster than stock BPV. Even though it only gets to ~20psi it gets there quick. I personally like the noise because you can't hear it all the time inside the car unless you turn the stereo off (and if you don't have a noisy boost gauge like mine) then it's all good. In the SRT-4 you can hear it over the stereo with the windows up and the heater running.

I'm not sure where you get the idea that these are junk. Look at Forge's website, they make a lot of custom parts. They might not be HKS, AGP or [insert name brand here] but IMO it's a quality product that simply needs a different set of springs specifically for the cruze. The product is solid, nice looking and isn't hard to install.

Anyone who knows anything will know right away what the noise coming from under my hood is.

I'm still going to try the yellow spring with a direct tap into vacuum and see what happens.
 
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I should not say there junk.I guess if i was a young hot rodder which i am not maybe it would be the in thing.I hot rod or have built up a lot of 60s and 70s muscle cars over the years my current summer car is a 1970 chevelle ss with a 390hp 396.At the dealer i specialize in late model corvettes.The cruze is a toy i bought as it was time for a new car for me and the wife.I find the 1.4T to be a very cool turbo engine and as we know some what detuned as delivered.The engine and trans tuned as Vtuner does it with the Stage 0 i find to be just perfect.I gave me that increase over stock i was looking for with sane boost at 18 or 19 psi on 93.No matter what is posted on this or other boards when boost is run higher meth injection is required.That is 1 reason you also see tricfectors premium tune drop off hp compared to Vtuner on the top end.Sorry for the rant
 

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Thanks for making this post. I also have noticed this with the yellow spring. I had not even tried the green spring. If there is any testing i can do to help i would be more than happy to dude.
 

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I should not say there junk.I guess if i was a young hot rodder which i am not maybe it would be the in thing.I hot rod or have built up a lot of 60s and 70s muscle cars over the years my current summer car is a 1970 chevelle ss with a 390hp 396.At the dealer i specialize in late model corvettes.The cruze is a toy i bought as it was time for a new car for me and the wife.I find the 1.4T to be a very cool turbo engine and as we know some what detuned as delivered.The engine and trans tuned as Vtuner does it with the Stage 0 i find to be just perfect.I gave me that increase over stock i was looking for with sane boost at 18 or 19 psi on 93.No matter what is posted on this or other boards when boost is run higher meth injection is required.That is 1 reason you also see tricfectors premium tune drop off hp compared to Vtuner on the top end.Sorry for the rant
Why on every post do I feel your force feeding us Vtuner? Even when its not even involved? I agree its great to have alternative options out there and Vtuner sounds very legit. I think honestly the only hotspot we saw with trifecta was when many people ordered over Black Friday and many tried to tune it during the holidays while support wasn't available. Some people even mentioned installing it not by the directions. For every Vtuned car out there are probably like 50-100 Trifecta tuned cruzes and "Most" had no issues and are happy with it. Either your being paid by Vtuner to solicit their tunes or your still trying to justify to yourself why you went with maybe a lesser known option. (I don't always choose the most popular path myself -just made a decision to trade in the iPhone 5 for the Nokia Lumina 920 Windows phone)
 

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OK no more Vtuner scouts honor lol And no i have no outside involvement with them
 

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Discussion Starter · #12 ·
OK no more Vtuner scouts honor lol And no i have no outside involvement with them
I'm cool if you want to be a VT who*e but at least hook us up with some deals! :) j/k

Thanks for making this post. I also have noticed this with the yellow spring. I had not even tried the green spring. If there is any testing i can do to help i would be more than happy to dude.
I wont get to the vacuum line test until next weekend at the earliest. If you have a chance to do that, then that would be cool.
 

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I like V tune and that is what I will probably buy. Sounds a bit more legit and I like the fact of having a hand held tuner. Their tune seems more in line with what the car is designed for (economy with a nice power increase) Oh and I am not getting paid by them either just some observations.
 

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Discussion Starter · #14 ·
I like V tune and that is what I will probably buy. Sounds a bit more legit and I like the fact of having a hand held tuner. Their tune seems more in line with what the car is designed for (economy with a nice power increase) Oh and I am not getting paid by them either just some observations.
This is a thread about the Forge aftermarket BOV/BPV. I have no idea where tunes came into this thread or why there is now an X vs Y conversation going on about them.
 
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Seriously though I am glad there are others with deeper pockets then me experimenting with this BOV and getting all the bugs out of it. Kuddo's to you!:bowing:
 

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I believe the Forge BPV/BOV is an upgrade in style of valve. Its a piston style compared to the stock diaphragm valve. I'm sure the longevity of this valve is better too.
 

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Did You ever end up testing the yellow spring again titan? Sorry to bump an old thread. Im just curious
 
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