Wish I knew the answer to this, I have the HKS BOV on my other car but it is recirculating and not open to the atmosphere. The APS kit I have is also recirculating and still sounds sweet when driving down the street, I don't see no reason to vent it to the atmosphere, I see no power gains from doing this other than maybe being louder.

 

BOVs are changed when you up the boost (people tend to do that on a stock lets say srt, evo, sti) cause the stock spring inside the bov is designed for x amount of PSI... people upgrade waste gates, turbos, bov for more boost..

but most of the time people just do it for the noise.. WPSHHHHHHHHHHHHHH =) lol. 95% of the time a stock bov is replaced by a aftermarket one with the same specs but instead of a recirculating it'll be a open atmosphere one.. you'll get a different pitch depending on brad.. greddy for example is adjust able (for noise) and makes a type-s and a type-r version type-s is good for 20psi while type-r was 30 something? sry i dont remember.

there are no power gains.. only time u see people saying power gains are (i believe) the older STi OR EVO i dont remember but this is only becuase it'll allow them to hold more boost...

no theres no cooling issues or anything.. to whoever asked

onlything a bov is for is to relieve the pressure between the turbo and the throttle body.. when you let off the throttle the butterfly plates slam shut on ur car.. but your still in (lets say) 6,000rpm.. so your turbo still wants to squeeze more air into it.. your waste gate reads manifold vacuum and "by-passes" the exahust gas so the turbo doesnt boost anymore.. but you still have existing boost in the pipes running from turbo to throttle body.. the BOV also reads manifold vacuum.. when theres no vacuum (throttle plate close) it'll releave the pressured air inside the pipping and into the exhaust (recirculating) or to the atmosphere.. why is it not carb approve? becuase the only air thats suppose to come out of ur car is through the tail pipe after passing the cats.

 

a couple things to add/say about what Klumzyee said .....

... a recirculating BOV relieves intake pressure(which is after the intercooler and before the throttle body) back into the Intake track Before the turbo, ... and then as he said, that is to relieve pressure when the throttle plate is closed, thus preventing the air 'trapped' in the intake track from being forced Back into the turbo which would actually be trying to 'spin' the turbo in the opposite direction from which it is 'normally' spinning.... or in other words, it is relieving the pressure surge created by the throttle plate closing partially, or all the way.
The air that a recirculating BOV is releasing back into the intake is After the MAF sensor, ... so the air is already "measured" and the car will not run rich because of the release of air out of the intake track. If a car that is 'designed' to have a recirc BOV uses one that releases to the atmosphere, it can/will run rich right after the "blow off" and possibly lead to issues if the stock ECU can not compensate enough for the air lost. 'Some' cars need 'at least' a piggy pack ECU to do so.

clear as mud? good.

 

Alright thanks Klumzyee and Nolimit! That is very helpful. I knew the function of the BOV but I was wondering which is better and why but now I understand.

So people only release to atmosphere for the sound? That's weak. I thought it had some sort of performance or efficiency benefit. I do NOT want it to be loud so I will just use the recirculating one that the kit comes with.

 

well, a car that uses a MAP sensor(speed density system) vice the MAF can use an externally venting BOV [easier] b/c the air is not measured at the actual "intake" like the MAF,
..... the MAP sys is a measure of the actual mainfold pressure, and used in conjunction with Intake Air Temp and possibly rpm (speed density calc).

Anyhow, if the BOV you are using can handle the Pressure you are running, then you are ok either way, there are recirculating BOVs that can handle higher boost too, but at those higher HP levels, the MAF sensor/unit may become a restriction and one would want to switch to a MAP based (speed density) system using aftermarket EM....
.... and then sometimes it is just easier to use an externally venting BOV when building a kit....
....... and of course some people like the sound!

 

or blow it off to the exhaust

 

blow what off to the exhaust????

A "BOV", or blow off valve, does Not connect to the exhaust, .... a Wastegate connects to the exhaust and can vent to the atmosphere as well, ... it serves a different purpose than a bov....

 

What Ty Baby?

How is she running since it is SOOOO Damn Hot!

M

 

WOW very very niccceee setup....i bet with the new gauges not many drivers would want to try to take you at a light huh lol

 

What up man, she's been running awesome so far. No complaints here. I'm exploring some options for building the tranny. More to come.

 

Cool.

Good to hear since you live on the sun out in Vegas!

Let me know if we can help?

M

 

Roneski,

You've got PM. Hope you don't mind but I just have a few more questions about the kit since I am getting close to pulling the trigger...

 

Sick Car,

Do you know what stall your gonna be running with the new tq converter? Are you going to keep it low enough to be a practical daily driver or is it gonna be race purpose?

 

dang. nice

 

The converter is on hold for now. I've pretty much put everything on pause until I get my hands on the parts to build the tranny with which is probably a couple of months out.