BOV and BPV v.explain

[Coozone]

ok so ive been reading the forums for the last week or so. ive noticed that everyone goes to a BOV replacement for our cars and so very few get an upgraded by pass valve.

can someone explain to me what each does and how each one effects our motor specifically? im hearing that a blow off valve requires a tune for it to run correctly and that a by pass valve is better for our engine.

i have a basic understanding of each but i could use some help here. i want to make a purchase soon and dont want to buy something that will backfire my wallet.

 

[SharkDiver]

I dont think most are getting BOVs..It seems to me that most get new BPVs.You do need a tune if you want to run a BOV as you said and that tune because its going to blow off metered air that the MAF sensor has measured and that will cause you to run even more of a rich fuel mixture.

 

[Coozone]

I dont think most are getting BOVs..It seems to me that most get new BPVs.You do need a tune if you want to run a BOV as you said and that tune because its going to blow off metered air that the MAF sensor has measured and that will cause you to run even more of a rich fuel mixture.

interesting. well im always a person of "function before form" and dont care to get a part because it sounds/looks better than something else. If an aftermarket BPV will prove to be a better choice then ill get one. is there an increase in any performance with a BPV over a BOV? will the BPV keep the engine from harm at high psi?

 

[Oxymoron]

A BPV recirculates the excess air pressure that builds during shfting. A BOV vents that extra air pressure out into the atmosphere. Our cars run BPVs because during shifts fuel is still delivered into the combustion chamber and the system counts on that excess air to be recirc'd back to maintain proper A/F ratios. If you VTA (vent to atmosphere) with a BOV your car will have lots of excess fuel during shift and backfire. Its not totally detrimental but is not proper for this setup. There are aftermarket ECU reprogrammers like the COBB AccessPort that will allow you to turn off the fuel delivery during shifts so that it is safe to run a VTA BOV.

 

[CT-Zoom-Zoom]

I posted this in another thread, I think it'll be valid here also...

Correct me if i'm wrong, but from what i've been looking at is that the MS3 has both a MAF and MAP, so running hybrid, VTA, or Recirc the ECM should be able to compensate. With that said, the system and how it works as I understand it. Air enters the intake track past the MAF on it's way to the turbos' inlet. The air then is compressed inside the turbo and heated, then sent to into the hot side of the intercooler. The air then travels threw the intercooler reducing it temperature. Then the air travels threw the cold pipe into the engines' throttle body. As the throttle blades open and the exhaust gases increase the turbo's impeller speed creating more pressure between the hot pipe off the turbo outlet and the throttle body. When the throttle closes the pressure in the cold pipe rises. Having no place to go the pressure pushes on the diaphragm of the BPV. The BPV opens slightly allowing the extra pressure of from the cold pipe to "vent" into a separate track leading back to the turbos' inlet AFTER the MAF. The way I see it is, that since there's only one MAF in the system, the computer can't tell how much air has been lost or gained after the BPV opens. Having a MAP in the system will. The MAP is able too look at the drop in pressure and balance the A/F ratio to keep the engine running. The way I see it is the ECM is already set to adjust the A/F ratio when it sees these drops in pressure within its allowed safety parameters. The ECM work with injector pulse width and IAC positions to keep the engine from starving for fuel and air. With an aftermarket BOV or Hybrid valve, you are able to adjust the tension on the spring. This spring pressure allows the piston or diaphragm to open at a certain amount. I would assume along as you have the right tension on the piston or diaphragm this will allow the ECM to keep the engine running without being too rich or too lean no matter how much or how little air goes back into the intake. As long as all the air between the hot pipe and cold pipe isn't depleted and the ECM can adjust within it's allowance everything should run as it was stock. An example of this would be having a BOV set too loose causing almost all of the air in the intercooler track to be depleted causing the ECM to adjust 100% rich, which would cause backfiring and stalling. Again, if i'm wrong please correct me.

Rob

 

[tru-boost]

not true at all. because of the way the fuel trims work on this car it isnt like that. the uce stores 4-5 levels of fuel trims. they are based off f throttle position. there are different trims at idle, low trottle, medium throttle, heavy throttle, and wide open throttle. every time you shift and release that air to the atmophere it will throw off your fuel trims a little. the more times you vent under a certain throttle position the farther off your trims in that category become. also this ecu doesnt use the MAP sensor for fueling. if it did my motor would be toast !! i run 21psi and have a map clamp set to 13psi. if the ecu only added fuel for the 13psi that the map sensor sees, i would be super lean, but i am not at all. the relies heavily on the MAF sensor fro fueling. if you run a full BOV or even a hybrid you are not giving the engine the amount of air it thinks it is recieving. the car may not run like s***, but you are losing power bcause of the adjustments the ecu has to make.
just buy this and call it a day.
http://siteground207.com/~protegeg/product_info.php?cPath=160_250&products_id=1075

 

[SuperStretch18]

not true at all. because of the way the fuel trims work on this car it isnt like that. the uce stores 4-5 levels of fuel trims. they are based off f throttle position. there are different trims at idle, low trottle, medium throttle, heavy throttle, and wide open throttle. every time you shift and release that air to the atmophere it will throw off your fuel trims a little. the more times you vent under a certain throttle position the farther off your trims in that category become. also this ecu doesnt use the MAP sensor for fueling. if it did my motor would be toast !! i run 21psi and have a map clamp set to 13psi. if the ecu only added fuel for the 13psi that the map sensor sees, i would be super lean, but i am not at all. the relies heavily on the MAF sensor fro fueling. if you run a full BOV or even a hybrid you are not giving the engine the amount of air it thinks it is recieving. the car may not run like s***, but you are losing power bcause of the adjustments the ecu has to make.
just buy this and call it a day.
http://siteground207.com/~protegeg/product_info.php?cPath=160_250&products_id=1075

QFT. Just get the forge BPV.

To the OP, people often use BOV and BPV interchangibly while posting. My guess is that most that have upgraded are using a BPV and calling it a BOV...

 

[Coozone]

not true at all. because of the way the fuel trims work on this car it isnt like that. the uce stores 4-5 levels of fuel trims. they are based off f throttle position. there are different trims at idle, low trottle, medium throttle, heavy throttle, and wide open throttle. every time you shift and release that air to the atmophere it will throw off your fuel trims a little. the more times you vent under a certain throttle position the farther off your trims in that category become. also this ecu doesnt use the MAP sensor for fueling. if it did my motor would be toast !! i run 21psi and have a map clamp set to 13psi. if the ecu only added fuel for the 13psi that the map sensor sees, i would be super lean, but i am not at all. the relies heavily on the MAF sensor fro fueling. if you run a full BOV or even a hybrid you are not giving the engine the amount of air it thinks it is recieving. the car may not run like s***, but you are losing power bcause of the adjustments the ecu has to make.
just buy this and call it a day.
http://siteground207.com/~protegeg/product_info.php?cPath=160_250&products_id=1075

thats the BPV i was looking into gettin with my next check

 

[Coozone]

QFT. Just get the forge BPV.

To the OP, people often use BOV and BPV interchangibly while posting. My guess is that most that have upgraded are using a BPV and calling it a BOV...

i can understand why they do that. the bpv is somewhat noticable outside the car and i have a few friends that thought it was a bov at first.

ill be getting that Forge BPV for sure now.

 

[Aaron@JSC]

I posted this in another thread, I think it'll be valid here also...

Correct me if i'm wrong, but from what i've been looking at is that the MS3 has both a MAF and MAP, so running hybrid, VTA, or Recirc the ECM should be able to compensate. With that said, the system and how it works as I understand it. Air enters the intake track past the MAF on it's way to the turbos' inlet. The air then is compressed inside the turbo and heated, then sent to into the hot side of the intercooler. The air then travels threw the intercooler reducing it temperature. Then the air travels threw the cold pipe into the engines' throttle body. As the throttle blades open and the exhaust gases increase the turbo's impeller speed creating more pressure between the hot pipe off the turbo outlet and the throttle body. When the throttle closes the pressure in the cold pipe rises. Having no place to go the pressure pushes on the diaphragm of the BPV. The BPV opens slightly allowing the extra pressure of from the cold pipe to "vent" into a separate track leading back to the turbos' inlet AFTER the MAF. The way I see it is, that since there's only one MAF in the system, the computer can't tell how much air has been lost or gained after the BPV opens. Having a MAP in the system will. The MAP is able too look at the drop in pressure and balance the A/F ratio to keep the engine running. The way I see it is the ECM is already set to adjust the A/F ratio when it sees these drops in pressure within its allowed safety parameters. The ECM work with injector pulse width and IAC positions to keep the engine from starving for fuel and air. With an aftermarket BOV or Hybrid valve, you are able to adjust the tension on the spring. This spring pressure allows the piston or diaphragm to open at a certain amount. I would assume along as you have the right tension on the piston or diaphragm this will allow the ECM to keep the engine running without being too rich or too lean no matter how much or how little air goes back into the intake. As long as all the air between the hot pipe and cold pipe isn't depleted and the ECM can adjust within it's allowance everything should run as it was stock. An example of this would be having a BOV set too loose causing almost all of the air in the intercooler track to be depleted causing the ECM to adjust 100% rich, which would cause backfiring and stalling. Again, if i'm wrong please correct me.

Rob

The vaccum in the manifold activates the valve opening, not simply the air pressuure in the cold pipe when the throttle closes.

 

[PhonyEVO_1]

Dammit.. I'm so confused now. I ordered a hardpipe kit and a HKS BOV. Should i have got the Forge BPV instead... I'm just looking to eliminate that Turkey call due to my Injen CAI. Should I install an HKS BOV and an Forge BPV... I was under the impression that the HKS BOV paired with my stock BPV will eliminate my turkey call and provide better performance. Owning a car with a turbo is becoming difficult to add mod's to than I anticipated...lol. So I guess I should look into an ECU programmer/tune??

 

[lestat13]

a lot of people do use bpv and bov interchangeably, but true, they are not the same thing. for someone looking for reliablity, upgrade to the forge bpv.

on the other hand, PhonyEVO_1, I have heard of many people running the HKS SSQ on VTA (vent to atmosphere = bov.... this valve can be run as either a bpv or bov) with no issues. This is because it is a pull-type valve while most of the others are push. I have no first hand knowledge of a dual setup.

I am running the hybrid turbo xs valve and have had zero issues with it. it is non-adjustable, the turbosmart is the adjustable one. mine is fixed 50/50 (half recirculated, half vent to atmosphere) all the time. works well, no leaks, and gives whoosh sounds. the turbosmart unit (albeit $400) can be adjusted to 100% in either direction, or any mix between the two. these hybrid valves, for the most part, give you the benefits of both bov and bpv at the same time.

 

[jaydubz]

Ok well this is my thing, please forgive my ignorance, but the whole BPV question has never really been answered for me on this car. Why would anyone change the stock BPV. Every bit that I have read suggest that there is always some sort of issue with the aftermarket units. What is wrong with the stock unit.

 

[MikeHTally]

I tend to agree, being a newb about the details of turbo-charging. From what I've gathered here, the stock units tend to leak. Don't know if mine does or not. I do know it's possible there's no end to performance mods and somewhere there's someone who's spent more money than you who will clean your clock (so to say).

I'm thinking of ordering a Forge unit next week. One of the guys at my dealership swears by the TurboSmart, but it's 'bout twice as much $. Once that's on, I may be done with power mods. I get as much of a kick by tossing her through some tight turns as seeing how fast/quick she is. She's plenty o' both now.