Fair enough. I personally like the sound of plumb back BOVs more, I
recon the best BOV noise I have heard is on a mates RS Liberty, with the
standard valve, and a unifilter ram pod style filter. On shifts it made
a noise like a big sigh, like it was just taking a breather for the next
run.

On Mon, 28 Jul 2003, Reeves Cameron wrote:

> I agree, all parts inside an engine are under stress, obviously some more than 
> others. I cant show you a turbo which has been damaged by the removal of a BOV, and 
> I sincerely doubt that anyone will be able to provide you with the undeniable proof 
> which you are after.
>
> Try spinning an engine at anything above 10,000rpm and chances are it wont be 
> running for too long. Turbos have to be made stronger because they do spin upwards 
> of 20-30'000 rpm. Chances are too that an engine will long outlive the life of a 
> turbo on that same engine.
>
> A 200SX BOV is designed to leak (there is a bloody great big hole in the middle of 
> it), and it is also NOT designed to control 3 and 4 fold increases in boost over the 
> original boost setting (std boost is 7 psi, not uncommon to see 20-24 psi with an 
> aftermarket turbo) - hence the relatively large aftermarket industry for BOV's. 
> These aftermarket bov's can decrease lag time, prevent leaking whilst under boost, 
> and ultimately, allowing your turbo to work less to reach the same boost.
>
> Dont get me wrong, I dislike externally venting/vent to atmosphere BOV's as much as 
> the next guy, but there are good reasons (see above) as to why an aftermarket 
> PLUMB-BACK bov (not the ones which make the big noises) can be a good purchase.
>
> As yet, the only reason I can see to buy an externally venting bov is for all the 
> rice boys to have some more noise and aid in attracting the police...
>
>
> -----Original Message-----
> From: Robert Charles Scealy [mailto:[EMAIL PROTECTED]
> Sent: Monday, 28 July 2003 03:38 PM
> To: [EMAIL PROTECTED]
> Subject: RE: BOV Sounds
>
>
> I will buy the argument that BOVs, in particular ones that plumb back
> into the inlet, will help to decrease lag etc pretty easily. About the
> slowing down of the turbine though, I will need more convincing (a
> broken turbo would be very convincing!). I accept that it will cause
> some ammount of stress, but it is hard to think of a mechanical part in
> a car that isnt under stress, otherwise there would probably be little
> use for it being there. What about valves - they are pounding up and
> down 1000s of times a second, being belted open by a cam and smashing
> thier way back down on a seat, and they will often last the lifetime of
> a motor, and they have to deal with metal-metal contact, where turbos
> only have to deal with metal-air (except for bearings).
> Also, even when you are under full throttle the air passing through the
> intake of the turbo is always trying to slow it down, while the exhaust
> turbine is trying to spin it much faster.
> Like I said though, I could be completely wrong - and if someone does
> indeed have a broken turbo that they can _only_ attribute to the lack of
> a BOV I will certainly eat humble pie. Comes down to a basic distrust of
> advertising in the aftermarkets parts industry I guess.
>
> On Mon, 28 Jul 2003, Reeves Cameron wrote:
>
> > anything which tries to stop something turning at 10's of thousands of rpm is 
> > going to stress on that piece of mechanics. it will also severely hamper the 
> > performance of your turbo as more energy needs to be exerted to spin the turbo 
> > back up to the speed at which is was operating before it was asked to slow down...
> >
> > every late model turbo car that I can think of has a plumb-back bov. air is 
> > directed from somewhere near the intake plenum back into the pipe from the airbox 
> > to the turbo.
> >
> > vent to atmosphere bov's (which I think is the one you could be thinking of), are 
> > the noisy ones. these are illegal.
> >
> >
> >
> > -----Original Message-----
> > From: Robert Charles Scealy [mailto:[EMAIL PROTECTED]
> > Sent: Monday, 28 July 2003 02:46 PM
> > To: [EMAIL PROTECTED]
> > Subject: RE: BOV Sounds
> >
> >
> > My old car used to do that with no BOV on closed throttle like you say.
> > I have always been a bit dubious of the theory that air rushing back
> > could damage a turbo though, has anyone ever had any damage that you
> > could attribute to the lack of a BOV? I am no expert though, so I will
> > quite happily hear arguments both ways. My main reasons for being a
> > little dubious are:
> > - If not having a BOV caused turbine damage, every factory car would
> > have a BOV to stop warrany claims etc, but many have no BOV with no
> > problem.
> > - The only place in writing that I have read about BOVs preventing
> > damage to a turbo is in advertisments for BOVs.
> >
> > On Mon, 28 Jul 2003, Reeves Cameron wrote:
> >
> > > with no bov you can probably achieve a similar sound. close the intake/off the 
> > > throttle and the air which would normally escape via the bov rushes back through 
> > > and hits the compressor wheel on your turbo...
> > >
> > > increases lag time and is a perfectly good way to break a good turbo to boot...
> > >
> > > -----Original Message-----
> > > From: Geordie [mailto:[EMAIL PROTECTED]
> > > Sent: Monday, 28 July 2003 01:59 PM
> > > To: [EMAIL PROTECTED]
> > > Subject: RE: BOV Sounds
> > > Importance: High
> > >
> > >
> > > He's looking for the chirp sound. I'd say that's just some sort of
> > > whistle/trumpet type of BOV, prolly looking at a few hundred bucks to get
> > > that dopey sound, but if that's what he wants then go for it.
> > > Far better off without a BOV, pain in the ass to set up, they leak, etc..
> > >
> > >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED]
> > > [mailto:[EMAIL PROTECTED] Behalf Of Ben
> > > Sent: Tuesday, 29 July 2003 5:42 AM
> > > To: [EMAIL PROTECTED]
> > > Subject: Re: BOV Sounds
> > >
> > >
> > > get rid of the BOV.....i dont have a BOV on my SR....she makes a CH CH CH CH
> > > CH CH noise when u close the throttle
> > >
> > > ----- Original Message -----
> > > From: <[EMAIL PROTECTED]>
> > > To: <[EMAIL PROTECTED]>
> > > Sent: Sunday, July 27, 2003 7:30 PM
> > > Subject: BOV Sounds
> > >
> > >
> > > > Hi List,
> > > >
> > > > Does anyone know what the relation is between BOV type and sound?
> > > > I have been asked how to get the 'pigeon' sound on a SR20 180sx.
> > > > I think he means the fluttery sound that is NOT wastegate flutter.
> > > > Supposedly you can get it by modifying the installation of a Turbosmart I
> > > valve.
> > > >
> > > > Wierd question, I know, but hopefully someone will be able to help out.
> > > >
> > > > Thanks,
> > > > Nick
> > > >
> > > > This message was sent through MyMail http://www.mymail.com.au
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >
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>


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