BOV Performance Benefits

If you have purchased a BOV, have you notice an increase in engine performance?

  • I have purchased a BOV and have noticed a performance increase.

    Votes: 10 38.5%
  • I have purchased a BOV and have not noticed a performance increase.

    Votes: 14 53.8%
  • I have purchased a BOV and have noticed a performance decrease.

    Votes: 2 7.7%

  • Total voters
    26

SCCA_MS3

Member
:
2009 Mazdaspeed 3
Looking into getting a BOV and would like to know if there are any actual performance benefits to the addition, or if it is more for aesthetics and makes the turbo sound more prominent? Any input would be appreciated. Thanks.
 
If anybody has any DH logs of a before and after that they could post. That would be helpful as well.
 
I was flipping through one of the car magazines yesterday while my girl grabbed a coffee in the bookstore, dyno tested a new evo x with a new bpv and a new bov and dyno'd a clear performance loss in the bov. Assuming since the new evo and our cars rely on mafs, this would be the same story with our cars. I will def tell you after having many bov setups on this car, you will lose a bit of power.
 
but i think that problem would go away if you relocate the MAF. Im not sure if you speed3 guys have this as an option. But i know for the MSP we would move the MAF to be after the BOV so the MAF is reading all the air that is goign to the engine.
 
the only time an upgraded bov (or bpv, bpv = recirc bov on this forum) will show a performance gain is if you are currently pushing more pressure than your existing valve can handle. this will cause it to leak and the air the engine thinks its getting won't make it there. a better bov would fix that problem.

if you dump air out of the closed system that has already been metered and expect to not have any adverse effects then you're a moron. after the air passes the MAF in this system it enters into a closed system.

a bov's function is to alleviate pressure that builds up when the throttle plate is closed so that the turbo doesn't have to fight hard to spin and damage itself. that's it. if the one you have is working correctly you will see no performance benefit.
 
Hence just upgrading your BPV to a Forge or equivalent (full recirc BPV) if and when you notice (DH would help) not holding boost pressures proving a leaky BPV. I can tell you that with the stock BPV my boost would drop dramatically sometimes all the way down to 11psi almost immediately after hitting max. Now with the forge I can hold 15-14 psi with no problem to 5200 RPM.
 
Of course...I have a Miata. It sounds cool though.

Sorry...I am of no help.
 
the only time an upgraded bov (or bpv, bpv = recirc bov on this forum) will show a performance gain is if you are currently pushing more pressure than your existing valve can handle. this will cause it to leak and the air the engine thinks its getting won't make it there. a better bov would fix that problem.

if you dump air out of the closed system that has already been metered and expect to not have any adverse effects then you're a moron. after the air passes the MAF in this system it enters into a closed system.

a bov's function is to alleviate pressure that builds up when the throttle plate is closed so that the turbo doesn't have to fight hard to spin and damage itself. that's it. if the one you have is working correctly you will see no performance benefit.


I totally agree with this, at best you will not have a performance gain (rated in HP). But there is a benefit to be had for a properly functioning BPV/BOV, for all of us with the gobbler. When you kill the turkey this means that the compressor is not being stopped by the air trapped by the throttle plate closing and thus when you shift and then step on it again your spool is sitting there waiting for you, you don't have to experience lag again....
 
I totally agree with this, at best you will not have a performance gain (rated in HP). But there is a benefit to be had for a properly functioning BPV/BOV, for all of us with the gobbler. When you kill the turkey this means that the compressor is not being stopped by the air trapped by the throttle plate closing and thus when you shift and then step on it again your spool is sitting there waiting for you, you don't have to experience lag again....

not to mention that the turbo will last longer.

Your best bet is to recirc a good quality aftermarket bov. Stronger than stock, but functions the same way. VTA is a comprimise of performance and long term durability for styling, unless you relocate your MAF as mentioned earlier... And in doing that, some are concearned with having the MAF on a boosted tube ruining the MAF eventually. Others have done it for years without issue...
 
also note that some piggy back EMS's don't like a reloc-ed MAF (i.e. unichip). Having the MAF on the pressurized side will work for X amount of time but it will fail sooner than on the un-pressurized side
 
also note that some piggy back EMS's don't like a reloc-ed MAF (i.e. unichip). Having the MAF on the pressurized side will work for X amount of time but it will fail sooner than on the un-pressurized side

I have to think there is another factor involved with failure than time. Maybe guys running it relocated aren't filtering intake charge as well? something? idk
 
the only time an upgraded bov (or bpv, bpv = recirc bov on this forum) will show a performance gain is if you are currently pushing more pressure than your existing valve can handle. this will cause it to leak and the air the engine thinks its getting won't make it there. a better bov would fix that problem.

if you dump air out of the closed system that has already been metered and expect to not have any adverse effects then you're a moron. after the air passes the MAF in this system it enters into a closed system.

a bov's function is to alleviate pressure that builds up when the throttle plate is closed so that the turbo doesn't have to fight hard to spin and damage itself. that's it. if the one you have is working correctly you will see no performance benefit.

Agreed.

I think that this question is better asked by saying the following:

At what psi does the stock MS3 BPV start leaking?

If you are boosting above this point you are loosing performance, because your turbo has to pump harder to keep the same psi level. Therby causing more heat in the intake and more restriction on exhaust gas flow to create the same boost pressure. Your VE of your engine would be less.

If the stock BOV holds the boost you are using there is no performance to be gained.

So at what PSI does the stock valve start leaking? And any data or DH logs that show this?
 
I totally agree with this, at best you will not have a performance gain (rated in HP). But there is a benefit to be had for a properly functioning BPV/BOV, for all of us with the gobbler. When you kill the turkey this means that the compressor is not being stopped by the air trapped by the throttle plate closing and thus when you shift and then step on it again your spool is sitting there waiting for you, you don't have to experience lag again....

*sigh* the msp has a similar sound to compressor surge but it is due to the abnormally small outlet on the bpv and small inlet on the intake, that's it....combine that with the type of bpv it is and you get that sound

try getting a larger outlet bpv like the bosch, then get a larger inlet welded on your intake...the sound will go away

BUT since there are a lot of people who still don't believe this, and this is for the speed3 guys not the msp guys, [/threadjack]


Jred is completely correct
 
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