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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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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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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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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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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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Discussion Starter · #21 ·
Did You ever end up testing the yellow spring again titan? Sorry to bump an old thread. Im just curious
No. After advice from Forge as well as Jerry, I decided to leave it on the green spring. At the moment I'm having many vacuum issues so I don't want to mess with anything else.

I'm going back to stock to take the car in but once I get it back, I'll give it a try with a vacuum source not from the solenoid now that I'm more familiar with the system. Will report back.
 

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Discussion Starter · #23 ·
if you bypass the current vacuum setup (stock) you will loose the ability to control boost with the tune, traction control and ABS function! And it will set a light for ABS/TC and CEL
Please explain. There is a single vacuum line that goes from the nipple on the BOV/BPV to the solenoid. There may be others lines that solenoid controls but I can't see them. So by blocking off the vacuum line to the BOV/BPV, how would I not be able to control boost? Boost is limited by the waste gate which has nothing to do with that vacuum line. Same thing for T/C and ABS.
 

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Discussion Starter · #25 ·
charge air bypass valve(BOV) is controlled by the ECM by utilizing a remotely mounted solenoid that is integrated into the charge air bypass valve to prevent compressor surging and damage it is also used to control boost during low traction event. the ecm controls the ground circuit #3060 by controlling (pwm) the amount of vacuum the BOV will see in order to control BOV.
So you're referring to low traction events which would make sense. I rarely encounter low traction moments here in SoCal, but I think that's enough reason to not make the mod - at least by itself. I'll give it a whirl anyway and see what the result is.

Thanks for the info.
 
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