Hey everyone,

Just got a notice from FedEX that my new BPV is sitting outside my door. yay.

I'm VERY curious to see the results when shifting at WOT without NLS. With my stock BPV, I fall to around 12-14 PSI when I shift VERY fast. Anyone every do a test between the stock bpv/green spring, and the yellow one? I have no problem doing that myself, but I was just curious


If there aren't any results by the time I get home I'll post my own

 

Just installed the BPV with the Yellow spring. took it for a drive and did some hard 2-3 and 3-4 pulls. no NLS. The new BPV doesn't hold the boost any better than the stock BPV, however it it just easier to access the bolts that hold it to the turbo.

It does sound very different from the original BPV. With the Yellow spring installed, I get this fluttery BOV kind of sound from it... the weird part is that it sounds like it's coming from under the seat rather than from the turbo (not sure if this is normal). I only get this fluttery sound when I let off the throttle when I'm in gear. The typical "PSHHH" is much louder and lasts much longer with the Yellow spring vs OEM.

Pros:
Looks better
Sounds better
No chance of it breaking

Cons:
spend $140 for something that doesn't perform better than the stock BPV

 

When I installed my BPV w/ the yellow spring I did get a bunch of fluttering at first. It drive me nuts and thought about ditching it and getting a HKS one but out of the blue the fluttering went away. I've had mine installed with the yellow spring pretty much going on two years and havent had a single issue since the fluttering went away. Didnt have time comparing stock vs Forge due to my stocker tearing the rubber seals.

 

So why would you think that the forge bpv would hold boost longer between shifts? You do realize that basically defeats the whole purpose of what a bpv or bov is designed to do. A correctly setup bpv/bov is designed to evacuate basically all boost pressure as soon as you lift off the throttle (create vacuum) to avoid compressor surge. If you hold boost when the throttle plate closes you're just asking for a load of turbo issues my man. What you're seeing on the gauge is basically just a delay in the gauge reacting to the pressure changes but I can assure you that you aren't holding 14psi between shifts.

 

AH This makes sense. I suppose I'm just dumb. It does make sense that it goes all the way into vac when you release the throttle. Do digital boost gauges relay the MAP info faster than the stock analog one?

 

Mechanical boost gauges display more accurately then electronic.

 

A mechanical gauge will tend to react a little quicker and display a little more accurately than most electronic gauges for the most part. Don't let the stock "mechanical" gauge fool you btw. It's actually not mechanical at all. Everything about the gauge is electronic including the fact that it recieves all of it's boost reference via the map sensors.

 

agreed, the point of BPV and BOV is to ditch boost like 09CobaltSS1 said so it doesn't damage the turbo from making it backspin, NLS is different and it holds the boost but you're as well holding the throttle open while you're shifting

 

I am getting a forged BPV for my B day 10 more days!

 

Quick question for you guys , does the YELLOW spring sound different then the stock GREEN spring? or is it simply just for higher boost levels? I am 20 PSI and spike at 22 which one would I use?

 

pros: it's not a cheapy plastic/rubber part that can rip/tear/age/crack/fall apart/have maintenance issues.
It's serviceable, can be lubed, and was made for increased durability and should last forever.

cons: people keep thinking it's some sort of replacement for a BOV, that it's supposed to change the sound of the car, that it's something that it's not and never was intended to be.


rever3nce use the yellow spring. The car will thank you for it.

 

Thanks sox I will do this when I have some time. I was debating about doing it upon install, but I always read leave the green one in. Guess I will be changing it out soon

 

hahahahaha. my laugh of the day.. psh...cracks me up how everyone wnats to blow money for sound. forge is a good unit though.

 

Matty! Glad I made your day.

 

what spring is everyone running on stage 1?

 

Thats what I am trying to find out, I just left the Green one installed. But I am hearing yellow now lol

 

so which spring r u running?

 

Let me be the first to wish u happy early Bday and enjoy the Bpv

 

Someone didn't see when that post was posted. Haha.

 

Yeah, Happy [belated] Birthday, lol!

 

the bpv has nothing to do with you holding boost between shifts... the car slams the throttle body to ~50% during a NLS and cuts boost.

as for the spring, you're supposed to match the spring to the vacuum pressure, it has nothing to do with boost.

 

im grabbing one this week, im just doing a lil update lol

 

Use the green spring if you're on a K04+ lol. I learned this the hard way