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Old 04-06-2010, 04:24 PM   #251
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I've red all threads and can't find the answer. Can anyone explain how the stock BPV works? what is the purpose of the little hole next to the big one VS the line that connect to the throttle body, any diagram?
tx,
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Old 04-08-2010, 03:41 PM   #252
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Old 06-16-2010, 12:35 AM   #253
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EXCELLENT article. This completely cleared up alot of questions i had. Thanks for a great post.

For anyone else, This will tell you exactly what you need to know. read it and feel enlightened.

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Old 06-23-2010, 03:16 PM   #254
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Quote:
Originally Posted by Phatron View Post
How do you know if your bpv is leaking and not holding boost?

I hear people say it....but i've never understood how they eliminate everything else down to the bpv?

i currently have a dom4xtr, spearco tmic, crushed bpv, perrin ebcs + hallman, 38mm tial ext gate.....

i can only get to 26 psi. More turns of the mbc dont do anything.

whats my process of elimination? how do i know that its the bpv?
I have his /\ crushed BPV and I only can hold 23.5psi, he also tuned my car and he said that it was leaking.

The way Ron crushed his BPV was not very elegant he probably crushed the BPV with a hammer. I am planning on crushing mine with vise and crush it 1/8th of an inch like Uncle Scotty suggest.

How much can't the crush BPV hold vs the drilled BPV? I am shooting for 25-26psi.

If I do both mods like the DSM thread suggested, how will it work on a subaru?

thanks
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Old 06-23-2010, 04:04 PM   #255
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Quote:
Originally Posted by juanmedina View Post
I have his /\ crushed BPV and I only can hold 23.5psi, he also tuned my car and he said that it was leaking.

The way Ron crushed his BPV was not very elegant he probably crushed the BPV with a hammer. I am planning on crushing mine with vise and crush it 1/8th of an inch like Uncle Scotty suggest.

How much can't the crush BPV hold vs the drilled BPV? I am shooting for 25-26psi.

If I do both mods like the DSM thread suggested, how will it work on a subaru?

thanks
It will hold boost to the point where it won't release the excess pressure efficiently resulting in crazy compressor surge. How do I know? Because I tried this.

The true way to test this, I found is that you need to have equal pressure on the top and bottom of the BPV. My crushed stocker, with the $.16 cent mod held 35+ psi when I tested it correctly. But that was way too much. My Forge Recirc valve with the red spring/no shims holds 30 PSI. I get a tiny bit of surge, but that's what I want. I want it to hold as much boost I can without getting a ton of surge. You want the valve to release that excess pressure as fast and efficiently as you can.

IMO, the Forge Recirc valve is a great buy. I tested it correctly and it works great at holding boost.
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Old 12-04-2010, 09:08 PM   #256
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Seven years, 255 posts, lots of pictures, and references from successful tuning threads from across the internet... and some people still didn't nor ever will "get it."

This thread is a microcosm of what goes on every day, in every field of endeavor. It's no wonder the abundance of Fail in this world.

Having posted two and a half years ago that I'd found the subject mod a perfect solution to my own issues with an '05 LGT, and now the happy owner of a new 2011 WRX, I decided to revisit this thread. It took longer to read than I imagined. That 05 LGT is still local and running strong, for reference, but my reading has to do with the present and my new WRX.

I will be doing this simple BPV mod to this car, too. It hasn't anything to do with cheap, however. It has to do with reliability and how I want my car to work. Virtually everyone I know, or whose history modding Subarus I track, that uses an aftermarket BOV eventually has a problem with it. The PROPERLY modded stock BPV, however, retains its excellent OEM reliability, eliminates any related boost leak questions, and more importantly, fulfills the function these gadgets were designed for in the beginning.

It isn't easy understanding how it works. It isn't easy even knowing why there is one at all. This thread is testament to that fact. The above post, #255, illustrates this perfectly. And to be honest, after these many hours today chasing references across the internet and reading every word of every post, I also know more than I did this morning. I knew it worked and I knew how it worked, but whereas before I had accepted the resultant mini-surge as an acceptable imperfect compromise I know now it is actually necessary.

The poster convinced himself his new, complicated, bling with springs, shims, bells and whistles is "great." He also wants that "tiny bit of surge," the very 'surge' so many other posters had hernias over. It is also 'surge' that not only has no effect on turbo reliability, but is an inescapable artifact of a BPV doing its originally intended job. Poster #255 arrived at the correct functional answer, but via a very specious route.

Why is that mini-surge good? Because while venting the pressurized air in the intake needs to happen, venting ALL that pressure, like most/all OEM BPVs, means every shift must start from zero boost again. ZERO. Ideally, we wouldn't have to vent one bit of that boost but practically we must vent enough to protect the turbo. The compromise is to find the balance between just how much boost we can keep to enable the best shift-to-shift power stream without compromising turbo reliability. That "tiny bit of surge" is in actuality not a problem, but the indication of a BPV working to the best interests of the driver.

The "$0.16 BOV mod," IMHO, creates a perfect BPV. YMMV, etc.
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Old 03-11-2011, 02:31 PM   #257
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Will this make any noise??
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Old 03-12-2011, 08:39 AM   #258
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the drilling part will.

unless you use a hand cranked drill, in which case it'll be pretty quiet.
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Old 03-12-2011, 10:23 AM   #259
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Quote:
Originally Posted by SeeeeeYa View Post

The poster convinced himself his new, complicated, bling with springs, shims, bells and whistles is "great."
Because we all know the aftermarket community cannot build a better part . Know whats great about them? They are adjustable/tunable. I used this mod for along time. It worked fine,untill I upgraded my turbo. My 18G moves alot more air than the stock 13T. I got alot more surge. Not alot of adjustment on the stock valve. Plus alot of the aftermarket valves have a larger bore to allow more air to pass through. Not all valves are the devil. This mod is a great solution,but it doesn't mean it will be everyones solution.

Last edited by quazimoto; 03-12-2011 at 10:31 AM.
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Old 03-12-2011, 11:11 AM   #260
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Originally Posted by quazimoto View Post
Because we all know the aftermarket community cannot build a better part .
i've been wrenching on cars for a while now, and i have to say that most of the time, the answer is "no, they cannot." the pile of broken or badly designed aftermarket parts sitting in my garage is a lot bigger than the pile of oem parts that failed.

Quote:
Know whats great about them? They are adjustable/tunable. I used this mod for along time. It worked fine,untill I upgraded my turbo. My 18G moves alot more air than the stock 13T. I got alot more surge. Not alot of adjustment on the stock valve.
what exactly do you need to adjust?
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Old 03-12-2011, 01:22 PM   #261
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Quote:
Originally Posted by ride5000
the drilling part will.

unless you use a hand cranked drill, in which case it'll be pretty quiet.
Lol so I'm taking that as there won't be even the slightest noise difference when shifting?
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Old 03-12-2011, 05:18 PM   #262
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I wonder how that will hold up in the long run.
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Old 03-13-2011, 09:25 AM   #263
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Originally Posted by New02scooby View Post
Lol so I'm taking that as there won't be even the slightest noise difference when shifting?
if you don't hear your oem bpv now, then you won't after the mod. it's the same air moving along the same path. the only difference is that the valve does have a slightly higher cracking pressure after the mod.

Quote:
Originally Posted by atrim View Post
I wonder how that will hold up in the long run.
it will last about as long as the untouched oem bpv will, which is probably longer than you'll have the car.
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Old 03-13-2011, 04:04 PM   #264
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Quote:
Originally Posted by quazimoto View Post
Because we all know the aftermarket community cannot build a better part . Know whats great about them? They are adjustable/tunable. I used this mod for along time. It worked fine,untill I upgraded my turbo. My 18G moves alot more air than the stock 13T. I got alot more surge. Not alot of adjustment on the stock valve. Plus alot of the aftermarket valves have a larger bore to allow more air to pass through. Not all valves are the devil. This mod is a great solution,but it doesn't mean it will be everyones solution.
Yes sir!

To everyone else, keep in mind that I bought the Forge because I crushed the OEM BPV AND did the .16$ mod and this equaled way too much surge, or flutter dump.

The simple fact is, I tested the Forge it and it works great. Doesn't matter what "route" I took to test it. Does it? No. I don't think so. Just as long as it was tested correctly. I don't just look at stuff and "convince" myself that it works without doing my own research/testing.

If I had to do it all over again, I would have just did the .16$ mod without crushing it...so there you have it.

Last edited by SVT_WRX; 03-13-2011 at 04:46 PM.
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Old 03-13-2011, 09:25 PM   #265
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Did the mod to my 11 WRX's plastic BPV... with a slight twist or two.

In addition to tapping the stock vent hole with a 1/4 20 tap the depth of the flange, and RTVing in a brass plug (made from a section of a 1/4 20 brass screw cut to 1/2" and dremel slotted), which I then covered with RTV, I next:

One, I drilled a tiny 1/16" hole 1/4" above the flange in the vent boss. My intention was to use the backside air chamber as a pneumatic brake on the opening/closing of the BPV. Despite all the theory I read that the flutter is compressor related, IMO it is the action of the BPV. Now, after my mod mod, there are circumstances where a slight fluttering can be noted but nothing remotely alarming. Shifting and flow of power has improved. Moderate driving can be done without constant low-boost blowoffs.

Two, For a filter I cut a piece of felt to fit, and used RTV to secure it around the vent boss, centered over the new vent hole.

Although this mod is easily reversed, once done its value is quickly apparent, and thoughts of removal disappear. I'm sure the air brake alters the piston dynamics as imagined, smoothing transitions, and dampening flutter... in my mind anyway.
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Old 03-23-2011, 02:38 AM   #266
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For those of us that like pictures, no matter how well explained the directions are...


The smaller hole that you need to tap is on the right in this picture.



Use a 1/4-20 tap and hold the tap upside down so the shavings fall down and not into the BPV



Drill into the side to pierce the air tunnel. This will allow pressure to vent to atmosphere (don't tap or put a screw in this hole).



Here you can see the opening to the air channel/tunnel.



Grab your teflon thread lock (I used Great White) and a 1/4-20 set screw. Glob some thread lock on and screw it!



Now ees done! Mine barely sits lower than flush with the mating surface, so tap that good!
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Old 03-23-2011, 02:55 PM   #267
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that's a very thorough job.

me, i just took a self tapping machine screw and drove it home right into the flange hole, drilled a vent hole, and was done.

no sealing, no tapping, etc.
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Old 05-18-2011, 09:44 PM   #268
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did this today on my 05 LGT.

i borrowed a 1/4-20 tap from a friend and then put one of these in there. 83 cents for a pack of 2 at home depot.




Last edited by Gil; 05-18-2011 at 09:53 PM.
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Old 05-19-2011, 02:10 PM   #269
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Quote:
Originally Posted by tmarcel View Post
I never thought about it until recently but how much boost is safe to run on the EJ205?
mine is a ej20 and its automatic..........but holds 22 psi
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Old 06-11-2011, 03:38 AM   #270
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I read every page.it's 2:30 am and i'm glad I stayed up.Thanks for the great information.
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Old 06-15-2011, 02:50 PM   #271
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Quote:
Originally Posted by ride5000 View Post
the drilling part will.

unless you use a hand cranked drill, in which case it'll be pretty quiet.
that just made reading this whole thing worth it

now my question is: im running 22psi and a GMBC on the td04 and i have a hard time keeping it at 22psi in those parts of my tune. to try and compensate for this ive been slowly adding wgdc which is up to 90% now. i dont think it should be that high, could this mod help with that situation or should i find ride5000's thread and install a mbc in addition to the GMBC?
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Old 06-15-2011, 03:08 PM   #272
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Quote:
Originally Posted by romanlynch View Post
that just made reading this whole thing worth it

now my question is: im running 22psi and a GMBC on the td04 and i have a hard time keeping it at 22psi in those parts of my tune. to try and compensate for this ive been slowly adding wgdc which is up to 90% now. i dont think it should be that high, could this mod help with that situation or should i find ride5000's thread and install a mbc in addition to the GMBC?
I bet I'm reading this wrong, but adding WGDC increases boost, not decreases it. Also, since you need about a 10% difference between your WGDC tables for your control system to function properly, the 90% might be in the High table but not the Low should making boost be the issue. To lower boost, reduce both tables proportionally.
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Old 06-17-2011, 08:35 AM   #273
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oh, forgot to say that it doesnt hold 22, i get 20ish mostly. i dont have a problem with overboost. also i have scaled the initial wgdc table to be within 8-10% of the max table.
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Old 06-17-2011, 01:47 PM   #274
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Very good.
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Old 06-17-2011, 10:29 PM   #275
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Figured I'd chime in since this thread has been resurrected.

I did this mod over 4 years and 60K ago with an 18g. Never had one issue. Ever.
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