Can anyone tell me why so many people are running BOVs on here and not BPV's, especially the ones who already have intakes? I'm interested in the same piece.
I come from NASIOC where the advice is always given to get a BPV and not a BOV due to bovs causing issues and increasing lag between shifts.
The stock BPV is perfectly fine on the stock turbo. To be honest I wasn't planning on upgrading the stock BPV but I found a deal I couldn't refuse on the TS Plumb Back.
As for sound, I'm using a stock intake with the K&N filter. The stock BPV is very quite. The TS Plumb Back is a little more audible especially at lower speeds, but not to an obnoxious level in my opinion.
The Plumb Back is also recirculates 100% of the air back to the intake like the stock unit. Only difference is that it's made of aluminum and is vacuum actuated instead of electronic, that's why it comes with that electronic plug. The theory is that it would increase response, but I personally don't notice a significant difference on the stock turbo. My advice: upgrade it when you upgrade the turbo.
Quick note on Subarus: BOV causes them to run rich during shifts because the stock BPV dumps the air back after the MAF. A BOV throws off the AFR since the actual amount of air intake is less than the metered amount. This isn't an issue with our motors since the ECU uses the MAP sensor instead.