BOV- What's the point?

[paulr33]

Well thats vic anyway. The stock airbox seems to block all of the induction noise. Try your car with the airbox out for a few seconds and you'll hear the stock bov. you just wont be able to hear it with the stock airbox and airfilter in.

[GTRman1992]

The defect for PODS is also sound pollution, your car must not exceed a certain db level when driving.

I think this is probably enforcable in all states, same as loud exhausts etc. Its just QLD police are nicer than other states and not so would up against us. Although the idiots down the Gold Coast are trying their hardest to make the police hate us all. Thanks to those clowns, police now have laws against traffic light racing, highway racing within the limit etc. My mate got done for "Displaying Speed".

[Ska]

Displaying Speed, bah that is just stupid! I must admit I have not yet been pulled over here on the coast since I bought my R33 (3 months ago), which will probably change once I get my pod installed.

[Jay95R33]

Just as a side note - in some cases not running a BOV can have the same effect as running a venting BOV (on a AFM'd car).

Where as the presurised air has now where to go when the throttle snaps shut (but the turbo is still spinning and compressing air), it can actually be blown back out the air filter !! This happend to me when I first got my car and later found that the factory BOV had been blocked off (must have been running an after market one).

I could actually hear the air coming back out the pod filter when I came off the throttle while under high boost! And as the AFM will messure air regardless of which direction it is going, it was dumping more fuel in cause it was thinking that the air was going IN through the AFM, not OUT as it was !!

This resulted in the occasional stalling problems.

I thought the car was fine with the blocked off BOV, until I unblocked it and instantly noticed a smoother and more responsive car !!

J

[GTRman1992]

Sounds a bit odd. How long do you shut the throttle between gear changes ?

[Jay95R33]

Well not every gear change is done like I'm on the track, it is a daily driver after all

But you think about the amount of air the turbo flows/compresses when your under boost at around 4-5000rpm. It's a damn heap of air, and it only takes a fraction of a second to build up against the closed throttle body. Then it has to go somewhere

J

[rev210]

I think if you would like to avoid the defects you should get one of those electronic fake BOV things.

Afterall it's only the sound your after isn't it? Because if anything replacing the factory one is at best going to do nothing at all for performance and at worst make your car slower.

[Roy]

I think if you would like to avoid the defects you should get one of those electronic fake BOV things.  

Afterall it's only the sound your after isn't it? Because if anything replacing the factory one is at best going to do nothing at all for performance and at worst make your car slower.

DISCLAIMER: Not wanting to start an argument.

For a std turbo road car i can see the sense in what you are saying, and tend to agree.

But say you have a modified Skyline with bigger turbo/s, and when on boost are now looking at 350-400cfm etc etc then i can definetely see the benefit of aftermarket BOVs.

Having looked at the internals of a few BOVs i suspect the Trust range are better then most due to the seal/diaphragm they use, and in the case of the Type R the larger bore which hopefully equates to superior venting ability.

Just like an aftermarket ECU can hurt driveability and performance if poorly installed the concept of the BOV shouldnt be blamed for poor installation or application

[Jay95R33]

I agree with you Roy.

The more HP then the more air required. And there comes a point where the stock BOV simply can't pass enough air to do it's job correctly.

BTW: just bought a new keyboard - pretty flash, but everytime I hit the space bar it clunks really loud.. Just a bit of trivia of you all... LOL

J

[rev210]

Roy,

We wouldn't be arguing at all. The factory style units have been used on cars with 700hp engines even on applications of upto 30psi or so of boost.

I've yet to see any hard evidence to prove the effectiveness of an aftermarket BOV over the factory unit, let alone a modified factory unit. Accelleration examples are nowhere to be found because without dodging the figures the aftermarket BOV has no advantage.

Show the conclusive proof and I'll change my mind. I have examples of cars with lots of power without the aftermarket ones.

[rev210]

Jay,

I know the factory ones can pass enough air because I've seen it. If people were more sceptical about aftermarket BOV claims less people would waste their money and get defects.

Put it to the manufacturers to prove their case and provide us with hard data comparisons. Lets not just take thier side and assume they are right afterall their main concern is making a profit (and who can blame them for that?).

[Jay95R33]

Dave,

I'm a big fan of sticking with the stock BOV as I haven't got any reason for changing it.

Although everything mechanical has limits, and I just can't see the stock BOV doing it's job effectivly on a T67 equipped RB25 running 22psi. Bit on an extreme example, but I'm sure you can see what I'm getting at.

I'm sure plumb back BOV are still legal ?

I'm sure a lot of people are in to much of a hurry to change the stock BOV. But everyone to their own. I personally hate the sound of a BOV, I'm not for the "look at me" thing.. Getting old I htink :headspin:

J

[TTT]

Roy,

We wouldn't be arguing at all. The factory style units have been used on cars with 700hp engines even on applications of upto 30psi or so of boost.

I've yet to see any hard evidence to prove the effectiveness of an aftermarket BOV over the factory unit, let alone a modified factory unit. Accelleration examples are nowhere to be found because without dodging the figures the aftermarket BOV has no advantage.

Show the conclusive proof and I'll change my mind. I have examples of cars with lots of power without the aftermarket ones.

Can you point me to an article where I can view this?

I'm not doubting anyone.

Everyone has a theory and I DON'T really want to hear it... I just want to see/read about these 700hp skylines with stock bovs..

and in terms of the modification you are talking about to the stock bov... Do you mean the blocking off of the small vacuum line that exists under it or is there other things that can be done..

I know that the MITSUBISHI guys simply crush these bovs (they are the same bov on the VR4 4G63 engines) and are able to run ALOT more boost and keep the stock item..

[JimX]

To everyone that thinks an audible atmo bov is just a "look at me" wank - do you hold the same theory about loud exhausts and pod filters? If anything a loud exhaust is more of a wank because you hear it constantly, not just between gear changes. Pods are still more often heard than bovs too.

[Jay95R33]

To everyone that thinks an audible atmo bov is just a "look at me" wank - do you hold the same theory about loud exhausts and pod filters? If anything a loud exhaust is more of a wank because you hear it constantly, not just between gear changes. Pods are still more often heard than bovs too.

Your right there, and I stand corrected

I think the reason why I said that is cause where I work we get the constant flow of people going past the 'cruise' street and manage to change gears 3 times in the space of 50 metres under boost, just to get their BOV to sound off LOL.

Looks funny..

J

[ed]

lucky I have a stock BOV and a sound legal exhaust

no "look-at-me" factor there hehehe

[TTT]

quiet ED.

The GETZ has a huge "look-at-me" factor

[ed]

hehehe, the getz is actually quiet zippy on suburban roads...struggles a bit on the freeway though

[JimX]

Your right there, and I stand corrected

I think the reason why I said that is cause where I work we get the constant flow of people going past the 'cruise' street and manage to change gears 3 times in the space of 50 metres under boost, just to get their BOV to sound off LOL.

Looks funny..

J

I think that's a fairer summary of it. Anyone can be a wanker with the noise/sideways effects of their car whether it's bov exhaust or tyre noise. Personally I don't like attracting attention. If I am driving down a quiet street I keep the revs low and therefore the exhaust pod and bov noises to a minimum. I think it's more a case (as like so many things are in life) of not what you have, but how you use it

[Roy]

We wouldn't be arguing at all. The factory style units have been used on cars with 700hp engines even on applications of upto 30psi or so of boost

I cant give you conclusive proof, but the example of the GTR (700hp i assume GTR) is interesting, after all they do run 2x BOVs standard.

I take it the modifying that you are talking about is putting in a stiffer spring??? Looking at how BOVs work my concern isnt so much with the leaking but with their ability to pass air. So using 2xstd ones gives the setup a fair bit of redundancy from the factory.

I would be surprised to see a 700hp GTST @30psi with std BOV working optimally.