Hello everyone, We would like to share what is the definition of BOV and the purpose of it
Most people confused between BOV (Blow of Valve) and BPV (Bypass Valve). For Subaru Original Blow off valve is actually referred to BPV not BOV. The definitions of BOV and BPV: -
Blow Off Valve - To release pressure from intake tract of a turbo car when throttle closes. It is a vacuum-actuated valve designed to releases the air to the atmosphere. When it releases, then you can here the sound of the BOV.
Bypass Valve - To release pressure from the intake tract of a turbo car when the throttle closes. It is a vacuum-actuated valve designed to recirculate the air back into the intake before the turbo inlet, but after the airflow sensor.
From the above definitions, you guys can differentiate the function of each valve.
Purposes of BOV/BPV - Without BOV / BPV, when the throttle closes and intake system under pressure, a pressure wave will travel back to turbo charger and can result the compressor wheel will stall or also known as "compressor surge". This is hard on the bearings and decreases the turbo's lifespan, and it also means the turbo will take longer to spin up the next time the throttle opened. So, To judge whether BOV/BPV is good or not. its depend at your owned risk. :)
but from our point of view, it is recommended and it is still depends on your modification level.
Is it necessary for Subaru turbo's to use aftermarket BOV/BPV - Not necessary, unless you go for higher boost level then the application of aftermarket is needed.
Downside and Negative effects of aftermarket BOV - It is not necessary and not recommended for stock condition turbo car to install aftermarket BOV, most aftermarket BOVs will require "tuning" (usually via supplied washers, a screw, or other mechanism on the BOV itself) to allow them to idle correctly and blow off at the right time.
The downside of releasing the air to atmosphere is that it has already been metered by the mass air sensor, and when it blows off, the ECU will be injecting the wrong amount of fuel into the cylinders. The engine temporarily runs rich, meaning too much fuel is injected into the cylinders. To resolve this issue, light tuned will be adviceable (Piggy back EM/ECU will helps the problem)
We conclude that If you are wanting to be 100% sure you arent losing any power from a BOV, and you are running under about 22PSI, you are best off sticking with a stock unit.
[Resources :- Nasioc Forum by Unabomber's Manifesto]
[Summarize by MrZeroWrx BSC]
Most people confused between BOV (Blow of Valve) and BPV (Bypass Valve). For Subaru Original Blow off valve is actually referred to BPV not BOV. The definitions of BOV and BPV: -
Blow Off Valve - To release pressure from intake tract of a turbo car when throttle closes. It is a vacuum-actuated valve designed to releases the air to the atmosphere. When it releases, then you can here the sound of the BOV.
Bypass Valve - To release pressure from the intake tract of a turbo car when the throttle closes. It is a vacuum-actuated valve designed to recirculate the air back into the intake before the turbo inlet, but after the airflow sensor.
From the above definitions, you guys can differentiate the function of each valve.
Purposes of BOV/BPV - Without BOV / BPV, when the throttle closes and intake system under pressure, a pressure wave will travel back to turbo charger and can result the compressor wheel will stall or also known as "compressor surge". This is hard on the bearings and decreases the turbo's lifespan, and it also means the turbo will take longer to spin up the next time the throttle opened. So, To judge whether BOV/BPV is good or not. its depend at your owned risk. :)
but from our point of view, it is recommended and it is still depends on your modification level.
Is it necessary for Subaru turbo's to use aftermarket BOV/BPV - Not necessary, unless you go for higher boost level then the application of aftermarket is needed.
Downside and Negative effects of aftermarket BOV - It is not necessary and not recommended for stock condition turbo car to install aftermarket BOV, most aftermarket BOVs will require "tuning" (usually via supplied washers, a screw, or other mechanism on the BOV itself) to allow them to idle correctly and blow off at the right time.
The downside of releasing the air to atmosphere is that it has already been metered by the mass air sensor, and when it blows off, the ECU will be injecting the wrong amount of fuel into the cylinders. The engine temporarily runs rich, meaning too much fuel is injected into the cylinders. To resolve this issue, light tuned will be adviceable (Piggy back EM/ECU will helps the problem)
We conclude that If you are wanting to be 100% sure you arent losing any power from a BOV, and you are running under about 22PSI, you are best off sticking with a stock unit.
[Resources :- Nasioc Forum by Unabomber's Manifesto]
[Summarize by MrZeroWrx BSC]
2 comments:
Hey man. Did the same article about this too on my site. Sure hard to differentiate sometimes eh, just by some term differences. :P
Incase you missed it.
http://vagclubbrunei.blogspot.com/2009/05/blow-off-valves-on-our-cars.html
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