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Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Wed Nov 25, 2015 10:16 am
by georryan
So I finally found a direct replacement diverter/bypass valve for our cars. It is a drop in replacement for the Subaru OEM part number 14471AA001.

Forge Motorsports makes one.

This valve also is modifiable. There are 4 springs that they sell to set the threshold of the valve as well.

I'm thinking I'm going to pick one up. The color on the website is a chrome, but they also make a black version as well.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Wed Nov 25, 2015 5:24 pm
by TurnNburn
A mazda protégé turbo BPV fits, I had an after market one that was labeled for that car. And im 99% sure a Nissan Juke BPV would also fit just by the way it looks and the bolt spacing but I have not tried bolting it to a TMIC to know for sure. just throwing it out there.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Wed Nov 25, 2015 9:56 pm
by georryan
I thought as much! I originally found this company because of an image they had for a protoge bypass valve. It looked just like ours but I couldn't figure out if the flow was the same direction in relation to the clocking of the manifold hose. Then I found out they made one for our cars as well. I like that its modifiable with different springs.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Thu Nov 26, 2015 3:02 am
by James614
I plan on getting one when I get my car out of storage (like a year and a half from now :-(). If for no other reason than OEM ones with a diaphram intact enough to handle 18psi becoming harder and harder to come by. Not so sure I want/need the different springs, but the option is always nice I suppose.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Fri Nov 27, 2015 9:11 pm
by Legacy777
If you get one, let us know how it works. So far the stock bypass valve has been holding the 18-19 psi of boost I've been throwing at it.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Fri Dec 04, 2015 4:07 pm
by mike-tracy
I have been using the supra (7mgte?) Single turbo bpv. Its all metal and functions exactly like the stock subaru part does. Same size inlets/outlet too.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Fri Dec 04, 2015 4:30 pm
by MConte05
I don't use a BPV. Amazing boost response. Right now I have a FMIC setup, but even before on the 06-07 TMIC I didn't have a BPV either. Turbos are in perfect shape. Plus on the smaller TMIC it makes that oh so great compressor chirp. :)

You can hear the chirp here:

And check the boost response on a rather large turbo (TD04HLA-19T):

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Fri Dec 04, 2015 9:05 pm
by TurnNburn
nice videos

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Fri Dec 04, 2015 9:33 pm
by robertpaige
Heres my thoughts: I have ran atmospheric, recirc, and closed off. I personally like not running a BOV. Heres the thing, from everything i've seen heard and read, journal bearing turbos under 20psi are unlikely to be damaged. I know a ton of 240sx guys with SR20DET and RB25DET engines, even 1JZGTE's that have T25 or T28 turbos the size of our TD04, VF39, and 16g's that bang rev limiter and rack their shit way harder than most of us Legacy guys and they don't blow turbos because of not having a BOV. Even guys with big turbos don't use BOV's, TimeAttack race cars and large large builds don't in some cases. I like the sound of compressor surge haha, this video is a perfect example of what not having a blow off valve with a large turbo sounds like.


Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Fri Dec 04, 2015 9:33 pm
by robertpaige
On topic, that Forge valve looks cool for anyone wanting to keep the stock look but have a nice upgrade. I, as well as many others, have broken our old shitty brittle BPV's, haha.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Sat Dec 05, 2015 12:56 am
by James614
That's intriguing. I've always heard compressor surge was bad. I even avoided a complete steal of a deal on a Neon SRT-4 once because I assumed the owner was a dumbass when he told me that he removed the BOV because you don't need it. It was a Neon though, so I don't regret missing that boat, lol.

But, the BPV is a VERY clunky space hog in the intake plumbing, and eliminating it would give me more freedom in using low-cost intake hoses and whatnot. Particularly that stupid 90* elbow.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Sat Dec 05, 2015 9:40 pm
by robertpaige
Go for it. I promise, it's tried and true for me and I've never had an issue with it. People will disagree, but I've done this with a TD04, VF39, and TD05 16g 12-20psi TMIC and FMIC for long periods and never had problems.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Sun Dec 06, 2015 12:43 am
by MConte05
Yep, and I've run two seasons on a VF11 with no BPV and 13 psi of boost. That's about.... 1000 miles of WOT full boost multiple shifting and 6000 miles of transits. People might scoff at "only" 1000 miles, but that's seeing abuse that no street car will ever see in its lifetime.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Sun Dec 06, 2015 12:47 am
by MConte05
Can really hear the awesome chirping going on in this one.


Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Sun Dec 06, 2015 12:51 am
by James614
You guys have me pretty sold that it's safe to try. But I'm just not a huge fan of the compressor surge. Maybe I need to hear it in person to really get a feel for it.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Sun Dec 06, 2015 6:31 am
by robertpaige
https://vimeo.com/147980276

here's an example, this was right when I finished the 20g swap on wastegate which is about 11psi. at 18ish the pitch is much higher. still sounds sick. haha.


Sent from my iPhone using Tapatalk

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Wed Dec 09, 2015 7:17 pm
by Legacy777
This article from GFB is pretty good and gives a balanced analysis vs. the sky is falling review if you don't use a BPV or BOV.

http://www.gfb.com.au/tech/tech-article ... ssor-surge

Because of my technical background I'd still personally run a BPV as it does help the longevity vs. not having one.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Wed Dec 09, 2015 8:22 pm
by robertpaige
Thanks Josh, that GFB article is very informative.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Wed Dec 09, 2015 11:56 pm
by Legacy777
Robert,

I removed the parts you posted because those are two snippets that support your preference of not running a diverter valve. If someone were to read those two snippets without reading the entire article they could take it out of context, and that is why I posted the link to the article, vs. copying and pasting snippets. It is up to the reader to read pieces of the article or read it in its entirety to form an opinion and make decision.

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Thu Dec 10, 2015 12:20 am
by robertpaige
Ahhhhh good point. My mistake!

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Fri Mar 31, 2017 3:41 pm
by Rattyleggy93
Sorry to bump this dinosaur but is there a write up on deleting the bpv?

Re: Direct Upgrade replacement for OEM Diverter/Bypass Valve

Posted: Fri Mar 31, 2017 6:55 pm
by Legacy777
Welcome to the BBS.

Are you wanting to replace the BPV with a blow off valve or just delete it all the way? Both are not good ideas and the latter about deleting it all the way is not good as that will cause compressor surge on the turbo.