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BOV or Bypass valve?

1070 Views 4 Replies 4 Participants Last post by  DiscountPowerParts
Ok, not trying to get picky, but I see that the stock BOV is referred to as having a "recirc line".

Does this not make the BOV just a bypass valve?

Also, I installed a CAI and am really happy with it. Thinking about upgrading the "BOV" with an aftermarket. One consideration for me is not to increase the sound level. It's my corporate car and I want to keep some (at least a little) amount of professional sound level to it.

Will the BOV's available allow the exhaust pressure to be put back into the system to eliminate some additional level, or do I need to look for a true bypass valve. Sound level is just about right as it stands right now.

Thanks guys.

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BOV and BPV are all the same. The difference is that on stock the hose is installed to recirculate. You can reinstall a hose on an aftermarket one.
Thanks for answering, but although they perform the same purpose, their design is different. The BOV's I've seen don't look like they have the outlet port that is intended to be connected back into the intake. They have a flared end on them.

I have a BPV for my SVO and it has three hose connections.....1 for vacuum and 2 for the pressure hoses. Do the BOV's being sold, have a "horn" (for lack of better terms) to purposely produce sound....or is that just a function of the fact that they outlet is being dumped directly into the atmosphere?


There are many different kinds of bov's some are designed to be really loud, some have different attachments for vta or recirc, some are vta only and some are recirc only. When you find one you want to buy go directly to the manufacturers web site and look at the specs for more accurate info.

On another note, the bov doesn’t have anything to do with the exhaust. It only deals with the compressor side of things before the air goes through the engine.

For a quieter ride, purchase a recirc type bov. For proper fuel mixture stay with a recirc type bov. And to not throw a CEL / code stay with a recirc type bov.
I installed a BOV that is vented to the atmosphere, but there are recirc style aftermarket valves available that fit in place in the OEM valve.

This is the one I used: BOV-H-RFL

This is the not so ridiculously load version: BOV-H

And this is the recirc that will sound very similar to the OEM one : RBV-H

The top two come with the recirc line plug.

The aftermarket Type-H adapter is located here: Speed6/Speed3 BOV adapter

If that is not making it as clear as mud, feel free to give me a call and I will chat with you a bit about the valves and installation. It took me about 15 min to install. Easy as pie to install and fun to hear when you shift under load!


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