bov sound when revving

[dsm144]

Ok I think I'm missing something. My friend just bought a srt-4 and whenever he revs up his motor in neutral the bov still whistles. How does his car do that without spooling up the turbo?

 

[Nasty Dream]

EDIT: see my next comment I think I'm misunderstanding

It is spooling the turbo a little. Is it the stock BOV?

Sounds like a Type-S. If it's aftermarket, it can be tightened up a little; it might be set too weak. I set mine when I got it, so maybe I'm forgetting. But yeah, sounds like the Type-S set too weak.

Set it as tight as you can before it makes that sudden sharp chirping noise. Chirping is bad. Just before that is perfect.

 

[GsXdSmKingGsX]

His car builds more boost pressure when not moving than yours. No big deal.

 

[Nasty Dream]

Wait, I was thinking you meant while he is pushing the gas, it whistles!

You mean after he lets off the gas in neutral? That's normal. It's just a different BOV than your used to.

 

[GRAVEDIGGER]

Yes, it's supposed to do that. If it's vented you will really be able to hear it. You are revving the motor and spooling the turbo and then slamming the throttle plate shut. That's what the bov is there for... To vent the pressure before it backs up against the throttle plate and causes damage to the turbo.

His car builds more boost pressure when not moving than yours. No big deal.

It's not building any pressure unless he's using an antilag setup, but it IS flowing alot of air and when you slam the throttle plate shut it goes out the bov. Simple as that.

 

[jtmcinder]

This is a great example of why calling that device by the wrong name can be damaging to your understanding.

Our cars do not have a blow-off valve. A blow-off valve, as the name suggests, is only opened by excessive boost in the intake path. It literally blows open. It is most often used by racing organizers to limit maximum boost.

Air only goes ever through a BOV in one direction: from inside the intake path to somewhere else (usually atmosphere).

A compressor bypass valve or diverter valve, in contrast, is opened by either or both of two things: excessive pressure in the intake path or vacuum in the intake manifold. The former pushes it open from below; the latter sucks it open from above. Thus, besides doing what a BOV does, a CBV can also open at idle, being sucked open by intake-manifold vacuum.

Of course, when sucked open from above, the air going through a CBV is going in the opposite direction from when it is pushed open from below. But it can still make noise while doing so and that might be what you're hearing. In fact, the noise that the air makes going through a CBV in the opposite direction is subtly different and, to some people, enjoyable. For more on this, search for the "screaming chicken mod," since the change in noise is one of the side-effects of this (rather questionable) mod.

 

[dsm144]

So basically his turbo is spooling more and is either vented or has a better bov? Mine is the stock recirc 2g

 

[GRAVEDIGGER]

So basically his turbo is spooling more and is either vented or has a better bov? Mine is the stock recirc 2g

It's not really spooling more, but the bov (or CBV if you will) is most likely vented and/or upgraded.

 

[TurboATM]

SRT4 bovs are mounted on the turbo...this mite also add to why it blows off at .00005 rpm.

And they can put some sort of plate with holes on it, alot of SRT guys call em 'ricer plates' or something...not sure what it does but i think that also affects it.

 

['97boostinGST]

SRT's make the weirdest noice in the world.
Yet everybody seems to like them.

 

[dsm144]

Everyone that sees our cars is like man where is your turbo? And he would kill your car all because he has a loud bov. Boy are they mistaken

 

[Tfitch90]

SRT's make the weirdest noice in the world.
Yet everybody seems to like them.

HA I think the srt exhaust sounds great if its done right.

 

[TurboATM]

HA I think the srt exhaust sounds great if its done right.

vvvrrrrrrrrrrrmmmmCCRRAAKKKLLAAABBAALALABACCKKAABBBBBOOOOOMMMsppsssshhh.


thats how they sound.

 

[GRAVEDIGGER]

vvvrrrrrrrrrrrmmmmCCRRAAKKKLLAAABBAALALABACCKKAABBBBBOOOOOMMMsppsssshhh.
thats how they sound.

I like that!

 

[TurboATM]

i had a 96 neon, straight exhaust and custom made JusMX141 muffler...sounded like a mini SRT without the turbo and bov.

 

[jed344]

My car with a 14b fmic and type s bov recirculated will not even blow off just under free revving. Now when i hit the 2 step thats a difference story. Loud bov does not mean its fast... contrary to popular belief haha

 

[dsm144]

My car with a 14b fmic and type s bov recirculated will not even blow off just under free revving. Now when i hit the 2 step thats a difference story. Loud bov does not mean its fast... contrary to popular belief haha

Thats the truth! Only ricers think the sound of your bov makes the car faster!

 

[jtmcinder]

SRT4 bovs are mounted on the turbo...this mite also add to why it blows off at .00005 rpm.

You didn't just confuse a wastegate for a CBV, did you?

 

[TurboATM]

You didn't just confuse a wastegate for a CBV, did you?

Is that what it is? i know this is where they put the "ricer" plates that make it bov so loud under almost no throttle. Whats the difference between that and a bov?

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[H4G64T]

I wish I had the like button right now.

OP, are you referring to an actual discharge of air pressure coming from his BOV or the little whistle you can sometimes here on deceleration and idle?

 

[jtmcinder]

That's an exhaust manifold with integrated wastegate. The CBV (which is the correct name for what you and they are calling a BOV) is nowhere near there; it's up on the intercooler to intake piping. If anyone put a plate on that flange, rather than just leaving it connected to the first part of the exhaust (not always called a downpipe on an SRT-4, but that's what it is), then the car would make less noise (and run like crud).

I think a few minutes with teh google is in order, dude. This is pretty basic stuff.

ps. the shiny thing on the right is the turbo ... thought I should add that at this point ...

 

[H4G64T]

Now, regarding the SRT-4 blow off valve, the stock blow off valve is built into the turbocharger manifold and is very quiet, and hard to see in the engine bay. That's why some SRT-4 owners who have never owned a turbocharged vehicle before, who expect to hear a loud whish between shifts or don't see a blow off valve may at first think their car doesn't have a blow off valve. The factory has done a great job at minimizing the BOV "whoosh" noise by designing an air intake system that's very quiet.

Have a question about the SRT-4

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[bryzenga]

That's an exhaust manifold with integrated wastegate. The CBV (which is the correct name for what you and they are calling a BOV) is nowhere near there; it's up on the intercooler to intake piping. If anyone put a plate on that flange, rather than just leaving it connected to the first part of the exhaust (not always called a downpipe on an SRT-4, but that's what it is), then the car would make less noise (and run like crud).

I think a few minutes with teh google is in order, dude. This is pretty basic stuff.

ps. the shiny thing on the right is the turbo ... thought I should add that at this point ...

I think he is referring to the valve that is on the compressor housing of the turbo. Pretty sure that is a BOV/Diverter valve. I've never actually looked at a neon's setup, but it appears as though it is one.
*edit-H4G64T just beat me.

 

[jtmcinder]

Funky.

So this "rice plate" thing is when they block off the CBV on the turbo and put it back where a normal car would have it (as in: after the IC)?

 

[GsXdSmKingGsX]

Funky.

So this "rice plate" thing is when they block off the CBV on the turbo and put it back where a normal car would have it (as in: after the IC)?

Correct. The "block off plate" is the official name for it.

http://www.turboneonstore.com/customer/product.php?productid=71