Seriously, what's the deal with BOV?

[Abilor]

I HAVE read and searched, so if you tell me to go read, go **** yourself. (enguard)

That said, why are some folks against BOVs, other than they run "pig rich" between shifts? And when you say they run rich, the idle itself isn't higher than 800 - 900 RPM is it?

I'm not even going to mention *which* BOV or BPV, just the concept in general. Can someone with experience across several models clear this up for me (and others reading - remember, a lot of lurkers abound who don't have time to comb relentlessly through the whole site)?

 

[Rotus8]

The MAF measures the amount of air put into the engine. The BPV recirculates the dumped air back into the engine so the ECU knows how much air to mix fuel with. A BOV vents some of that air back to the atmosphere, but the ECU doesn't know about it and so adds fuel as if all the air was still in the engine. When this happens, the engine gets too much fuel and runs even richer than it does with the stock setup. Aftermarket bypass valves, properly set up, and configured with the recirculating fitting don't have this problem.

 

[Captain KRM P5]

there is no performance benefit to venting open on a blowoff or bypass valve. this is done for the cool sound, and nothing more. anyone who has a legitimate reason as to why they think thats not true please say so

rotus is on point with his post. if a loss of power and efficiency, as well as perhaps some fuel economy, isn't a good enough reason to not do it, i am not sure what would be. besides, with a decent recirculated valve and a decent cold air intake, you'll still be able to get that wicked sound.

 

[dkswim]

a properly designed recirc can also spool faster. more of the turbo dose not unspool as much as a vta so you dont have to regain as much spooling.

 

[Renzokuken]

there is no performance benefit to venting open on a blowoff or bypass valve. this is done for the cool sound, and nothing more. anyone who has a legitimate reason as to why they think thats not true please say so

rotus is on point with his post. if a loss of power and efficiency, as well as perhaps some fuel economy, isn't a good enough reason to not do it, i am not sure what would be. besides, with a decent recirculated valve and a decent cold air intake, you'll still be able to get that wicked sound.

+1 BOV= ricer

 

[Abilor]

The MAF measures the amount of air put into the engine. The BPV recirculates the dumped air back into the engine so the ECU knows how much air to mix fuel with. A BOV vents some of that air back to the atmosphere, but the ECU doesn't know about it and so adds fuel as if all the air was still in the engine. When this happens, the engine gets too much fuel and runs even richer than it does with the stock setup. Aftermarket bypass valves, properly set up, and configured with the recirculating fitting don't have this problem.

Thank you, this makes a lot of sense. Yeah, the sound is cool, but I like that you gave an alternative. So that said, what do you make of turbosmart valves like over at SU? Do these really give the best of both worlds so to speak, acting as a BPV under light/normal conditions? Or is not a true BPV, and only recirculating? Is there a difference? Better to go with, say, a Forge BPV and a Cobb SRI or CPE CAI? I do want some serious growl and "pssshhh!," but I won't forsake performance for bling...

Thank you for your answers thus far!!!

(nana)

 

[Abilor]

+1 BOV= ricer

Renzokuken, your ride is serious; what do you have in this dept?

Edit: Forge. Ah so...

 

[Renzokuken]

Renzokuken, your ride is serious; what do you have in this dept?

Edit: Forge. Ah so...

Honestly, Any BPV is better than the stocker. That thing leaks if you up the boost. I went with the Forge cause Its a quality piece, Its fucken affordable, It can run recirculated, and it STILL has a nice sound. Not too loud and obnoxious, but just enough to remind you that you have a turbocharged car lol. I originally had the HKS, the sound got annoying.... QUICK. it was waaay to loud. In Recirculation, it had no sound whatsoever. That just annoyed me.

 

[Alexsered]

I HAVE read and searched, so if you tell me to go read, go **** yourself. (enguard)

That said, why are some folks against BOVs, other than they run "pig rich" between shifts? And when you say they run rich, the idle itself isn't higher than 800 - 900 RPM is it?

I'm not even going to mention *which* BOV or BPV, just the concept in general. Can someone with experience across several models clear this up for me (and others reading - remember, a lot of lurkers abound who don't have time to comb relentlessly through the whole site)?

Our BOV do not hold Boost. Anyone that has a speed3 with a boost gauge that taps into the boost line to read boost can tell you that, when they floor it in 5th gear, the boost will hit 15.5, but start dropping down to 10 or so psi. I thought something was wrong with my car, but I replaced my BOV just because I heard a bunch of crap about the one that I bought, and they were making crazy claims on HP gains.

Needless to say, I never returned the BOV, just by replacing the BOV, I spiked to 18 psi, and held boost perfect at 15.5 in 5th gear. You have to understand, I was lucky sometimes to hit 15.5 with my stock BOV.

I'm not saying my BOV is super special or anything, I just know now my stock one was a piece of crap and I should have replaced it as the very first thing.

So basically, I spooled faster, and held boost alot better with replacing my BOV, and it doesn't sound louder than stock. I definatly don't do anything ricer, my car still looks completely stock.

I would tell you to get a boost gauge, and than replace you BOV and see the difference. Don't believe the people that say it doesn't do anything, the stock BOV is a plastic pile of crap that does not hold boost, its very leaky.

 

[DaleNixon]

Is the factory BPV weak to protect the factory turbo?

 

[Abilor]

Okay, this is all sounding good. When you're flooring it in fifth, is this at a local track? I'm more and more tempted to pay for someplace I can run around in circles at 110 - 120 so I can feel it and not freak about public safety.

Also, having no fear of tools or work, I have zero to none experience really working on cars. The fanciest thing I've ever done is rig up a two amp system and replace the speakers and a subwoofer in my volvo (that was funny, a kloogy volvo with kickass beats). I have an electrical background, so I have no fear of wires either. How hard is it, realistically, to install a boost gauge? Will I be chucking my warranty out the window?

 

[mazdaspeedster3]

BOV and BPV are dif but the same, remember a blow off valve does just that, blows it off (dont go there) and by pass valve (which is what MS3 come stock with) recirc, by passing it back in.

 

[Alexsered]

Okay, this is all sounding good. When you're flooring it in fifth, is this at a local track? I'm more and more tempted to pay for someplace I can run around in circles at 110 - 120 so I can feel it and not freak about public safety.

Also, having no fear of tools or work, I have zero to none experience really working on cars. The fanciest thing I've ever done is rig up a two amp system and replace the speakers and a subwoofer in my volvo (that was funny, a kloogy volvo with kickass beats). I have an electrical background, so I have no fear of wires either. How hard is it, realistically, to install a boost gauge? Will I be chucking my warranty out the window?

It depends on what BOV you get, I don't remember which one it was, but there is one that people had a problem fitting because it was a really tight spot or something. Synapse has a really good writeup on how to instal their BOV, it is really not that hard.

Dealerships will vary from dealer to dealer, I've never had any issues with my BOV.

 

[DaleNixon]

Okay, this is all sounding good. When you're flooring it in fifth, is this at a local track? I'm more and more tempted to pay for someplace I can run around in circles at 110 - 120 so I can feel it and not freak about public safety.

Also, having no fear of tools or work, I have zero to none experience really working on cars. The fanciest thing I've ever done is rig up a two amp system and replace the speakers and a subwoofer in my volvo (that was funny, a kloogy volvo with kickass beats). I have an electrical background, so I have no fear of wires either. How hard is it, realistically, to install a boost gauge? Will I be chucking my warranty out the window?

I just plugged my dashhawk into the OBDII port. Instant boost gauge without all the nasty warranty voiding.

 

[Abilor]

I just plugged my dashhawk into the OBDII port. Instant boost gauge without all the nasty warranty voiding.

No s***... I'll check that out.

 

[Renzokuken]

stay stock, stay slow... That's my opinion on warranty LOL

 

[SuperStretch18]

stay stock, stay slow... That's my opinion on warranty LOL

Do as I say, not as I do? (wiggle)

 

[08cosmic3]

The Cobb intake with the Forge BPV is loud and sounds just as loud as any BOV I've heard. I wish it were not so loud but I want the performace, so I deal with it. This combo is also the cheapest, easiest to install and uninstall.
The quality is first rate as well. Good luck on finding the Cobb SRI. Get the Forge and wait for the Cobb.

 

[daonly1around]

IMO if you want a cool sound run an open wastegate dump hahahaha

 

[H3br3w_Ham3r]

What's different about the setup for a BPV to run in recirc? I've seen the option for recirc on certain intakes. Does this mean that some aren't able to run in recirc?