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Discussion Starter #1
Some say an after marker BOV reduces lag?
 
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A BLOV relieve's pressure to prevent surge of the turbo when letting off the gas. I couldn't see how a blov would reduce lag. As it's design purpose is to discharge.
 

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spoolinto40 said:
A BLOV relieve's pressure to prevent surge of the turbo when letting off the gas. I couldn't see how a blov would reduce lag. As it's design purpose is to discharge.

:werd:
 

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It will reduce lag inbetween shifts from not slowing the turbo's down from the throttle plate being closed. It will not help outside of shifts.

Danny
 

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If you don't have a BOV as godelfer said it will cause a surge in the system in which the turbo will "compressor surge" causing them to lose some of their spool, so when you shift it has to wind up a bit more than it would if the system is evacuated (blown off).

So basically, between shifts you'll be able to build a bit more boost (less lag) but other than that it's the same.
 

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hqen2000 said:
If you don't have a BOV as godelfer said it will cause a surge in the system in which the turbo will "compressor surge" causing them to lose some of their spool, so when you shift it has to wind up a bit more than it would if the system is evacuated (blown off).

So basically, between shifts you'll be able to build a bit more boost (less lag) but other than that it's the same.
What about WOT shifts though?
 

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But they do help reduce a little bit of lag between shifts. A venting BOV will allow the turbo to free wheel for that split second you close the throttle to change gears. Without a BOV, as the others said, the air charge stacks up and starts to put put resistance on the compressor wheel, slowing it down.

A BOV won't reduce lag in any other situation where you need to spool the turbo(s) out of a vacuum state, like cruising, and then getting on it.

In the case of a WOT shift, the BOV will do nothing, and you shouldn't have any lag, but I honestly don't see a WOT shift as being a good trade off to bouncing your engine off the rev limiter. You might loose a little boost, shifting WOT, but if you do it quick enough, I can't see the engine making any vacuum since momentum will keep the turbo(s) spinning and the throttle body will still be open.
 

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Discussion Starter #10
Espeefan said:
But they do help reduce a little bit of lag between shifts. A venting BOV will allow the turbo to free wheel for that split second you close the throttle to change gears. Without a BOV, as the others said, the air charge stacks up and starts to put put resistance on the compressor wheel, slowing it down.

A BOV won't reduce lag in any other situation where you need to spool the turbo(s) out of a vacuum state, like cruising, and then getting on it.

In the case of a WOT shift, the BOV will do nothing, and you shouldn't have any lag, but I honestly don't see a WOT shift as being a good trade off to bouncing your engine off the rev limiter. You might loose a little boost, shifting WOT, but if you do it quick enough, I can't see the engine making any vacuum since momentum will keep the turbo(s) spinning and the throttle body will still be open.

gotcha, thanks for explaining!

is there a way to know if the stock BOV is bad and needs replacing?
 

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s14roller said:
All you need to know is no one really talks about BOVs reducing lag...
That's the only reason I bought one.


Without it, your boost is blown back through the turbo compressor when you press the clutch in, causing the blades to stop. When you let the clutch out, and roll onto the accelerator, you have to spin that turbo back up to XXpsi from 0psi. Supposedly, this is "harder" on the turbo because it has to stop suddenly. No proof exists, and it's very controversial.

With it, the blades keeep spinning like they were making full boost, so when you let the clutch out after shifting, the turbo is right there, waiting on you.

Sound... eh, BOV's sound too kiddish to me> I run dual HKS SSQV's, and their chirp is just a by-product that I have to deal with.
 

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Well its better to be safe than sorry with a bypass valve.... But please don't get it just because you like the sound....

And if it did reduce turbo lag, you would be seeing guys with T-88's running 10 BOV's :lol:
 

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Discussion Starter #14
Jaxx said:
Well its better to be safe than sorry with a bypass valve.... But please don't get it just because you like the sound....

And if it did reduce turbo lag, you would be seeing guys with T-88's running 10 BOV's :lol:
10 BOVs haha... i think one will do... but i think id like to pick one by sound and as long as it releases pressure like it shoud. I mean i dont want to just pick one and then it will drive me nuts in about a week!!

I hear greddy ones are good HKS ones are apexi good blitz good, etc... so out of those id prob pick by sound, since i have a wide range of good picks.

i want something like this

http://www.935motorsports.com/media/BlitzBovMK4.mpg
http://www.935motorsports.com/media/blitzddjza80.mpg

i believe they are both Blitz DD
 

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what i want to know is if i can get the same effect as a BOV without the sound. u know, so the mother doesnt find out about the turbo(she knows nothing about cars but she'll be asking what it is)
 

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Go4shoped said:
what i want to know is if i can get the same effect as a BOV without the sound. u know, so the mother doesnt find out about the turbo(she knows nothing about cars but she'll be asking what it is)

bwhahahaha :wtflol:

All you gotta do is not get into boost and the BOV should never go off, or shift really slowly.
 

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Go4shoped said:
what i want to know is if i can get the same effect as a BOV without the sound. u know, so the mother doesnt find out about the turbo(she knows nothing about cars but she'll be asking what it is)
Are you serious?? :stickpoke
 

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Uhh, just run a stock BOV. Its just that simple. If you feel its not enough run 2. Dude if you need to fool your mom on parts on your car, maybe something else is wrong. but either way, just tell her its a bov. and it releases excess pressure. i doubt she will deduce that means you have a turbo. :stickpoke:

Dont WRC cars have a custom setup so that they are always in a couple pounds of boost no matter what. I dont remember how its set up exactly anymore though.

Alex
 

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ScrewDrvr said:
WRC cars run with no BOV. They do this to never loose boost between sfifts and on/off the gas.
Loose boost between shifts? Uh oh, where'd my boost go?!? Really, those guys never let of the throttle with their sequential transmissions. They don't have too. Heck, most the time they use the brakes and throttle together.
 
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