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 > > > > > > > > > > > > > > > > > > > > > ************************************************************************ > > The information in this e-mail together with any attachments is > > intended only for the person or entity to which it is addressed > > and may contain confidential and/or privileged material. > > Any form of review, disclosure, modification, distribution > > and/or publication of this e-mail message is prohibited. > > If you have received this message in error, you are asked to > > inform the sender as quickly as possible and delete this message > > and any copies of this message from your computer and/or your > > computer system network. > > ************************************************************************ > > > > > > > > > > --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[EMAIL PROTECTED]/ ---------------------------------------------------------------------
