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Old 05-16-2006, 02:38 PM   #1
Scooby Newbie
Member#: 115079
Join Date: May 2006
Default STi diverter valve question

First off, hello to all. I am a new member, coming from legacygt.com.
I own an 05 LGT, stage II, 250WHP @ ~17psi peak. (it was 205 stock, so that is about ~300 CHP estimated)... you know the bit I am sure. Dynoed at Pure-Tuning in NW Ohio on a Mustang Dyno... +1 for Pure-Tuning for those who are local. Ok, now for the question....

I did a search but came up short because the diverter valve has so many names, BOV, BPV, diverter, bypass, recirc valve, etc, etc. Annoying I know.

The stock LGT diverter valve sucks. It is all plastic and leaks intentionally. I assume upgrading to the stock STi diverter valve would be an improvement... but not certain. Not many people with LGT's do it, because you have to purchase a $50 adaption bracket (LGT diverter bolt pattern is different). Most just go with a custom setup.

What is the general concensus regarding the STi diverter valve? I am contemplating designing my own converter bracket, and modifying the direction of the recirc (if need-be) to try out the STi valve. I guess at this point I could also try out any valve that is made for the WRX / STi bolt pattern.
Thanks for any input, it is greatly appreciated. I am sure I can snatch up a STi diverter valve in the For Sale section... I have already looked a bit.
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Old 05-16-2006, 04:07 PM   #2
Scooby Newbie
Member#: 107778
Join Date: Feb 2006
Chapter/Region: TXIC
Location: Hizzurst, Texas
2006 Legacy GT Sedan
Obsidian Black


This is 'wcbjr' from the LGT forums. Here's a snip from Unabomber's Manifesto.

Are aftermarket BOVs necessary with Subaru turbos? No. The OEM BPV is perfectly fine up to 20psi of boost (WRX/STi). For applications using higher boost levels, an aftermarket BOV/BPV should be considered.

Is the STi BPV better than the WRX BPV? No. They are the same. However, the JDM STi BPV will hold more boost as it is physically different than both the USDM STi BPV and the WRX BPV. The specific PSI rating of the JDM STi BPV is unknown.
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Old 05-16-2006, 04:25 PM   #3
Scooby Newbie
Member#: 115079
Join Date: May 2006

Thanks... from searching, it seems the STi Bypass valve leaks as well. Maybe I will just get a univeral 90deg bypass valve with 1" inlets and outlets (the kind that hook up to a hose on each end), and make a plate with a nipple for a hose.
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Old 05-16-2006, 04:49 PM   #4
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Member#: 38016
Join Date: Jun 2003
Chapter/Region: SCIC
Location: 5/10 No Limit Holdem
2017 STI
2016 F-150 XLT


Not sure if this helps but my friends 05 sti has a FP Green and his stock bpv would leak so I suggested a turbosmart 38mm bpv and he bought one and it works great. It holds 21 psi all the way to 7200 rpm now.
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