Do I need a BOV?

Discussion and technical advice the SW20 MR2. 3S-GTE, 3S-GE, 3S-FE etc
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2mad
Posts: 5983
Joined: Sun Feb 28, 2010 12:11 pm
Location: uk

Re: Do I need a BOV?

Post by 2mad »

orangejunkie wrote:Although i`ve been registered on here for a few years now, i`ve not posted too often. I`ve tended to sit back and use the forum for help advice and tips.

However this thread has got my interest so i thought i would share my views on it.

Running a small tuning business with a friend, you can imagine we get asked this question a lot!

I have always traditionally been against Bovs. Any car i have bought that had one on, has swiftly had it removed going right back to my Rs Ford days. I also prefer the sound not running one provides and even spent some time `tuning` the sound this makes by altering the shape, size and material of the intake pipe. As mentioned, this sound is the `air wave` or pulse in the inlet system, so an alloy inlet pipe will change the sound from a flutter to a `chirp` depending on boost level.

We get on very well with a well known Turbo company who have been helpful when i have approached them on this topic.

Their general view on it was that it largely depends on the boost pressure that was being run. Taking a 400hp car as an example, to achieve that kind of power, you`re going to be flowing a considerable amount of air (around 1.5 bar + ) . At that point, not running one would add additional stress to the thrust bearing and also surprisingly the Turbine wheel. (This apparently takes more of a beating than the assumed Compressor wheel)

His suggestion was, below this you`re ok, although its not `recommended` As for which BOV, he suggested Re-circ is the preferred method as the inlet is an area of low pressure, meaning the charged air will be drawn in and help continue the Compressor speed.

Who knows. I`ve gone back to an OE re-circ and the car doesnt really feel any different, but then i dont drive mine that hard!



I had an rs white lightning it loved being bov (dumpvalve) free but it was the 90's so i fitted one coz it was cool init lol .. my r21 turbo hated being bov free at 1.3bar ... my supra loved it at 1.1 bar .. my mr2 ct20b hated it at 1.1bar ... what im saying is every cars different .... if your running low boost you might get some extra performance on your gear shifts not having one ... high boost its going to chatter like f/ck ... hurting your turbo ... each to there own on this topic do whats right for your cars performance :thumleft:


Edit .. for the record no bov does not cause stall ... the compressed air in the system once the throttle snaps shut had no ware to go but back past the compressor blades ... making that cool chatter sound ... not great for the turbo but also not a deal breaker ... you can go years n years bov free ... like i said what ever works for you :thumleft:
jimGTS
Posts: 14024
Joined: Tue Dec 14, 2004 1:40 pm
Location: North Kent

Re: Do I need a BOV?

Post by jimGTS »

just for fun, my old car

no BOV
sounded ace.

closely listen to 1st to 2nd gear changes, full boost it almost immediate to the point where it sounds like a mishift or something, but im well into 2nd gear.
i did NOT get this response running an atmos BOV.


https://www.youtube.com/watch?v=KsnTSwfvWmY

https://www.youtube.com/watch?v=Bk8tuySvTrE
masterbateson
Posts: 547
Joined: Sat Jan 24, 2015 7:09 pm

Re: Do I need a BOV?

Post by masterbateson »

cant see 2nd vid says private.

That 1st vid I couldn't hear anything apart from a sound that sounded a bit like someone pulling down a big zip? :?: :? :?:

I'm assuming thats not the cool turbo chatter noise? didnt here any sneezing BOV tho :lol:
jimGTS
Posts: 14024
Joined: Tue Dec 14, 2004 1:40 pm
Location: North Kent

Re: Do I need a BOV?

Post by jimGTS »

masterbateson wrote:cant see 2nd vid says private.

That 1st vid I couldn't hear anything apart from a sound that sounded a bit like someone pulling down a big zip? :?: :? :?:

I'm assuming thats not the cool turbo chatter noise? didnt here any sneezing BOV tho :lol:



how can you not hear it? lol

listen to the "pigeon" flutter noise between the shifts, its clearly audible even with the car 100s of feet away from camera.
2mad
Posts: 5983
Joined: Sun Feb 28, 2010 12:11 pm
Location: uk

Re: Do I need a BOV?

Post by 2mad »

jimGTS wrote:
masterbateson wrote:cant see 2nd vid says private.

That 1st vid I couldn't hear anything apart from a sound that sounded a bit like someone pulling down a big zip? :?: :? :?:

I'm assuming thats not the cool turbo chatter noise? didnt here any sneezing BOV tho :lol:



how can you not hear it? lol

listen to the "pigeon" flutter noise between the shifts, its clearly audible even with the car 100s of feet away from camera.


Haha my car did pigeon shifts even with a khs valve .. aaa memories .
manuelk1
Posts: 70
Joined: Mon Jul 13, 2015 3:58 pm

Re: Do I need a BOV?

Post by manuelk1 »

Has anyone got the re circ pipe that feeds the air back into the AFR intake from the BOV that I could buy?
2mad
Posts: 5983
Joined: Sun Feb 28, 2010 12:11 pm
Location: uk

Re: Do I need a BOV?

Post by 2mad »

manuelk1 wrote:Has anyone got the re circ pipe that feeds the air back into the AFR intake from the BOV that I could buy?


Post this in wanted adds .. some one will help you :thumleft:
2mad
Posts: 5983
Joined: Sun Feb 28, 2010 12:11 pm
Location: uk

Re: Do I need a BOV?

Post by 2mad »

2mad wrote:
manuelk1 wrote:Has anyone got the re circ pipe that feeds the air back into the AFR intake from the BOV that I could buy?


Post this in wanted adds .. some one will help you :thumleft:


Aw sorry just re read what you said .. it does not make that much difference .. in one scenario you vent to atmosphere .. the other you vent back into you air box or intake .. its much of a much-nes... just make sure its a quality bov :thumleft: .... loved my hks :D
masterbateson
Posts: 547
Joined: Sat Jan 24, 2015 7:09 pm

Re: Do I need a BOV?

Post by masterbateson »

I'll try again and put my hearing aid in this time and turn the amp up on the computer. :lol: :clown:
masterbateson
Posts: 547
Joined: Sat Jan 24, 2015 7:09 pm

Re: Do I need a BOV?

Post by masterbateson »

I might have this sort of noise when I'm accelerating or more to the point trying too and the boost is playing up :cry: :?:
What clue might that give?

Its weird some times it boost like a mofo and goes like a stabbed rat, and other times you put your foot down and its like the boost is missing/weak.

Still wondering if i have a intermitantly sticking waste gate?

Im going to try running without a BOV for a bit and see how she runs, Its a Bailey BOV on at the mo and I have heard they can be problomatic, dont know how much truth there is in that?
2mad
Posts: 5983
Joined: Sun Feb 28, 2010 12:11 pm
Location: uk

Re: Do I need a BOV?

Post by 2mad »

masterbateson wrote:I might have this sort of noise when I'm accelerating or more to the point trying too and the boost is playing up :cry: :?:
What clue might that give?

Its weird some times it boost like a mofo and goes like a stabbed rat, and other times you put your foot down and its like the boost is missing/weak.

Still wondering if i have a intermitantly sticking waste gate?

Im going to try running without a BOV for a bit and see how she runs, Its a Bailey BOV on at the mo and I have heard they can be problomatic, dont know how much truth there is in that?



Yes there a week and i mean very week dumpvalve .. hks for life .. wooo :thumleft:
masterbateson
Posts: 547
Joined: Sat Jan 24, 2015 7:09 pm

Re: Do I need a BOV?

Post by masterbateson »

here's an interesting article

http://www.imoc.co.uk/technical/article/dumpvalves.htm

dont know how good the info is but I would have thought its by someone knowledgeable.
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