So as I'm deciding on whether to go DT BPV or just a new stock one, it has me wondering. Is it possible to rebuild a BPV and maybe upgrade the spring? Obviously DT is replacing the spring, so I was just pondering if there were such options out there. Different springs available, something between stock and the DT one? Reading a few posts, I see some different thoughts on how the DT version feels on a DD, I"m second guessing myself. I'm used to driving some rowdy cars (Z06, built hi revving small blocks, etc...) so I'm thinking I would barely notice this, but I also don't want something that is annoying. My car is a stock daily driver (for now) with what I believe is a faulty BPV. Future mods include, CAI, pulley, and maybe some exhaust (more for sound than I think it actually needs it).

 

Why do you believe it's faulty

 

83k+ miles, unknown history and I get slow boost building and a max of 8psi.

 

Have you checked your sc oil and for intake leaks

 

That sounds more like an intake leak. Check out the intercooler boots and intake hose

 

You could spend hours finding the right spring...
But there is a vacuum diagram.... And the seating surface for the moving parts...
So for the $$, IMO, just buy new.

 

Reading the post...you can ZIPTIE the bpv closed to avoid bypass to test it...

 

Our valve is designed with spirited driving in mind, so it will react differently when driven in a DD application. It uses a stiffer spring, as well is adjusted to close more effectively.

The car will transition from vacuum to boost sooner, which creates an "on/off" feel to some, and while it may not be for everybody (we'll be the first to admit it isn't) it was originally designed to remedy the yo-yo of a fatigued BPV, as well as quicker boost generation.

Personally I wouldn't recommend going out on your own to redesign the wheel, we've got hours of trial and error testing into our valve.

As Zippy said, try zip tying the valve shut and see what happens. If the car builds quicker/better boost you are in the market for either a stock valve or our valve.

Stock cars make about 11 PSI, so you're a little low but there are also variables that can change boost readings; altitude, humidity, temperature, rev range, quality of the engine overall.

I've seen cars as low as 9 PSI stock, so you may be on par if everything checks out.

Nick

 

the BPV also had a butterfly adjustment on it, in case there is a leakby. as for the spring, I don't think there is readily available information on the spring rate and the coil size. otherwise yeah im sure you could find something inbetween both the DT spring and OEM spring. I have a spare BPV on my desk right now. which im sure ill play with to see if what I can find out about it. then eventually swap it into my car when I know it has no leaks.
the intercooler boots also crack over age, and can leak through there


OEM car makes about 9-10 psi of boost at sea level, higher you go in elevation less psi. JCW makes about 11-12psi. 15% is about 14-15psi, 17% is about 15-16.5 psi

 

I can't say I ruled out every absolute possibility that it's not an air leak. I did poke around trying to find something obvious. Maybe I'll attempt the old starter fluid trick and see if I can find anything. My experience with other cars that had any kind of stray intake/vacuum leak was that you would have some rough running/idle issues. Other than running a little bit like a dog, it runs like a clock. For those that had read my other post, I'll apologize for the rehash here. My comment about being a dog is that we also have a 2005 MCS (wife's) with 145k miles. We bought it in July, enjoyed it so much that we bought the '04 MCS (mine) in December. There is a night and day difference in how they run from a performance standpoint. The '05 feels more like a caged animal waiting to be released, which is easy to do without even going WOT. It tops out around 10.4 psi boost and seems to come on much faster. The '04 tops out at ~8 psi and seems to come on much slower. I realize there is a slight bump in power and gearing for the '05, but the difference is much more than that (the 2 psi in boost difference and slower transition to boost maybe more like it). Both cars are visually stock under the hood and I have no indication that any performance work has been done prior to us buying them. Anyways, the consensus on the other post is that the BPV seemed like the likely culprit.

As for the rebuilding the BPV question, I'm not looking to recreate the wheel. As an engineer in my day job, I'm just prone to like to like to take stuff apart and tinker. I was more or less passing time on a boring Wednesday night and trying to learn something to see if anyone has done it or looked into it.

 

I am an engineer as well, and I bought an extra intake manifold, supercharger horn, and a BPV. the manifold and horn are getting polished, ported, and painted. while I wanted to see how these BPV are

 

If you modify it post up, would like to see what you find .

 

You might also try a full reset of your ECU. It may have 'learned' some bad habits in its previous life.