what are the problems with BOV?

[OHIO SKY RL]

What would the impact be on my 08 sky RL if i installed a BOV that vented to the atmosphere? Are there any aftermarket mods to install to that wont deminish my performance or give me any problems? If so where can i find them? Also is the any company that makes a spacer plate or equivalent to make stock turbo vent to atmosphere? (anything similar to the Dodge SRT-4 Mopar Blowoff Plate)

Also looking for an update on the GM stage upgrades?

[shabby]

The mopar guys have it easy, their staged tunes compensate for venting to the atmosphere. You'll eventually throw some map/maf error codes when you install a bov on our cars.

[Bogie]

I'm curious as to why you wish to do this?

[OHIO SKY RL]

So is the only impact of venting to the atmosphere throwing trouble codes or will it give me a stutter or even stall as well?

[Bogie]

Originally Posted by OHIO SKY RL

So is the only impact of venting to the atmosphere throwing trouble codes or will it give me a stutter or even stall as well?

I'm not a mechanical expert on the SKY, but I thought we have Compressor Bypass Valves (CBV). It is my understanding, and I'm sure someone more knowledgeable will chime in to ensure I have it correct, but the CBV vents back to the compressor...which helps keep the turbo spooled when throttle is closed.

What happens with a BOV? If you vent to atmosphere, you don't get the spool assist of the CBV, which will increase turbo lag. If it's placed after the air flow sensors (or placed in a manner that disrupts the MAF reading), then the ECM will send the wrong mixture command to the injectors. If the BOV has vented to atmosphere, this usually results in the engine running rich...which can cause all sorts of problems, and is why you might throw an engine code.

Again, I'm not an expert on the Ecotec...just know a little about turbos. If anyone would like to compliment or correct what I've said above, please feel free to do so.

[Jay_Sin]

Bogie pretty much got it. Not a good idea unless you want to sacrifice performance for the little woosh sound you get. Get a CAI, that will make the sound more noticeable.

[byronsky]

I have the Hahn kit with the BOV that vents to atmosphere. This is one of my favorites things about this car!! I absolutely love the sound when I get off the gas......

[sidejam]

I would love a BOV that vents to atmosphere. One advantage of a BOV is at vacuum, it stays shut! With the diverter valve, at part throttle it stays open a bit. When you push the throttle, while a BOV will already be shut, a diverter valve has to close first.

I know this opinion isn't that popular on this forum, but I also love the sound of a BOV going to atmosphere. Right now I still have the stock DV, but I have debated about putting in an aftermarket BOV and just venting it back into the intake between the MAF sensor and the turbo.

[Bogie]

Originally Posted by byronsky

I have the Hahn kit with the BOV that vents to atmosphere. This is one of my favorites things about this car!! I absolutely love the sound when I get off the gas......

But isn't the Hahn BOV part of a package that includes a new turbocharger? The BOV is integrated into the turbo upgrade package; it's all part of the DESIGN.

Our stock Borg-Warner Turbos have the diverter integrated into the turbo itself, which is not complementary to a BOV further downstream.

[Jae]

I think Hahn is developing a new recirculating valve that is larger than stock and directs the airflow back into the compressor. There is a noticeable lag when shifting at higher rpms which I believe comes from the compressor wheel slowing down between shifts and losing boost. It is very annoying to me so hopefully this new valve will improve this issue. The stock valve is small and may not allow enough blow-off when the throttle body closes creating some backpressure which slows the turbo down, thus losing boost and increasing lag. A bigger valve might take care of this problem.

[bronzestarsky]

In installed the Mopar BOV on a Dodge SRT-4 I used to own, and I loved that sound of it venting to atmosphere everytime I shifted. Made me notice other cars with BOVs a little bit more (WRX's, modded Hondas and Acuras, etc). I don't think it really did anything performance-wise, but then for mostly street driving, I wasn't expecting it to. Not sure how the turbo system is set up on the Sky, but I'd definitely make sure it won't interfere with that diverter thing that's been mentioned. The install on the SRT-4 was pretty easy, and didn't throw any engine codes or have any potential warranty issues.

[Booster_RL]

If your goal is simply to achieve the whoosh sound, instead of sacrificing all that nice extra air that is being returned to the compressor and keeping your dual scroll turbo humming across your entire powerband, just buy the little kit you can stick under the hood that makes a fake BOV sound. Ricers w/o turbos use it all the time.

[RedlineBlue]

Okay... prepare for a stupid question. Folks want to vent the BOV to atmosphere so they get a "woosh" sound (whistle?) when they let off the gas. That would imply the redline does not do that.

When I let off the gas I get a whistle (woosh?) sound that many people say the redline does that because of the turbo and it's the BOV. If the whistle is normal and we are really talking about a "woosh"?

Bogie you did a REALLY great job of answering my whistle question in the other thread, this just seemed contrary to that unless we are talking a "woosh" and not a whistle.

I DO understand that the exhaust still being diverted to the turbo at reduced throttle to keep it spooled up on the redline and this may not be typical of other turbos.

[Booster_RL]

Originally Posted by RedlineBlue

When I let off the gas I get a whistle (woosh?) sound that many people say the redline does that because of the turbo and it's the BOV. If the whistle is normal and we are really talking about a "woosh"?

Same here, all the air cannot go back to the compressor so you do get a little whistle but a BOV makes a LOUD 'whoosh' sound because quite a bit of the exhaust gas vents to atmosphere. I can barely hear the wastegate on this car at speed when I let off the gas, BOVs you can hear quite well even at high speeds.

[centric]

Why you would want a sneezing car is something I have never personally understood.

[sidejam]

Originally Posted by centric

Why you would want a sneezing car is something I have never personally understood.

I just love the sound. I guess it all comes down to personal taste...

Looking at your sig, I'll assume you're more about big V8 muscle. So, I could see how a BOV wouldn't appeal to you.

[Jay_Sin]

I don't know about him, but I love turbo fours. Although, I'm not going to take my BOV and make it vent to the atmosphere just because is sounds cool. I'd much rather leave it the way it is, because I realize there is no performance to be gained by venting to the atmosphere. Actually, there is performance to be lost.

[SaturnSkyDude]

When I had my Fujita CAI on the whooshing sound was much more pronounced. This is a fairly inexpensive mod and some compaines claim a HP increase as well.