I've dug and read older BOV threads. But all I seem to get is mixed feelings and pro's/cons. Like the con of the car needing that back pressure because it's designed to have it, and if you install a BOV, you're loseing that pressure and causeing problems. But then I read about a hybrid? I'm assumeing that means it still gives air to the system, but wouldn't SOME air escapreing for the noise be kind of bad as well? what are people doing these days for BOV's?
Just another BOV question/clarification...
- Thread starter Haxir
- Start date
- :
- 2008.5 MS3
Many people prefer the stock BPV over aftermarket on this forum. The stock BPV is fine as long as it is not leaking.
Back pressure? I think you're confusing exhaust with intake. BTW: even on the exhaust side, back pressure is not a good thing for a turbocharged engine. The more free flowing the better for turbos.
Turning to what I THINK you mean, our engines use a MAF sensor to control engine management. MAF is mass air flow - a measurement of the mass of the air column crossing the sensor in your intake. Once it measures that mass, the ECU calculates the amount of fuel and the duration of the fuel "shot" that will be sent directly to each combustion chamber.
Why is knowing that important? Because that fuel is going to get shot into the chamber regardless of whether all the measured air gets there. But if you replace your bpv with a true bov or even a hybrid, you are going to divert some of that already measured air to atmosphere rather than keeping it in the intake and sending into the combustion chamber through the intake valves.
You see, a bpv releases pressure in the post-turbo boosted side of your intake when you let up on throttle or when shifting, because it's not needed then and cal put an unnecessary load on the turbo. But that air needs to go back into the intake and not out to atmosphere, in order for the air and fuel ratio to match.
So, please use a true bpv (bypass valve) and not a bov or hybrid and make sure you are recirculating the air so that it stays in the system. Your car will run smoother, will not stumble, will not backfire (afterfire actually) during shifts, and will produce more power. Most importantly, it will have correct air to fuel ratio.
BTW: the stock bpv will hold boost as well as or better than any of the other products on the market up to the maximum safe boost capacity of your stock turbo. They rarely leak. So, unless you can prove it is leaking, you will see no power gains from replacing it. Any change will be. at best, just a change in sound.
Turning to what I THINK you mean, our engines use a MAF sensor to control engine management. MAF is mass air flow - a measurement of the mass of the air column crossing the sensor in your intake. Once it measures that mass, the ECU calculates the amount of fuel and the duration of the fuel "shot" that will be sent directly to each combustion chamber.
Why is knowing that important? Because that fuel is going to get shot into the chamber regardless of whether all the measured air gets there. But if you replace your bpv with a true bov or even a hybrid, you are going to divert some of that already measured air to atmosphere rather than keeping it in the intake and sending into the combustion chamber through the intake valves.
You see, a bpv releases pressure in the post-turbo boosted side of your intake when you let up on throttle or when shifting, because it's not needed then and cal put an unnecessary load on the turbo. But that air needs to go back into the intake and not out to atmosphere, in order for the air and fuel ratio to match.
So, please use a true bpv (bypass valve) and not a bov or hybrid and make sure you are recirculating the air so that it stays in the system. Your car will run smoother, will not stumble, will not backfire (afterfire actually) during shifts, and will produce more power. Most importantly, it will have correct air to fuel ratio.
BTW: the stock bpv will hold boost as well as or better than any of the other products on the market up to the maximum safe boost capacity of your stock turbo. They rarely leak. So, unless you can prove it is leaking, you will see no power gains from replacing it. Any change will be. at best, just a change in sound.
From your posts on another thread I see that you have the same intake I am running, the MS CAI. The air filter is right in front of the left front fender well. That location and the metal construction of the intake make the stock bpv very noticable, pretty loud actually.
And, yes, it's best to keep all of the metered air inside the intake and eventually into the engine. Will going VTA (vent to atmosphere) "harm" your engine? Probably not, but it sure will have a negative effect on performance and drivability.
And, yes, it's best to keep all of the metered air inside the intake and eventually into the engine. Will going VTA (vent to atmosphere) "harm" your engine? Probably not, but it sure will have a negative effect on performance and drivability.
i just posted this in another thread, but it certainly applies here...
i know guys will have mixed feelings about this, but unless you suspect you are having an issue with your stock bpv, don't even bother replacing it. myself and alot of others on here have used aftermarket bypass valves only to go back to the stock one. sure the clanging swords sound of the forge bpv is sexy, but in daily driving the stock piece is alot smoother. i was ready to trade in my car before i reverted back to the stock one, and fell in love with the car all over again.
i know guys will have mixed feelings about this, but unless you suspect you are having an issue with your stock bpv, don't even bother replacing it. myself and alot of others on here have used aftermarket bypass valves only to go back to the stock one. sure the clanging swords sound of the forge bpv is sexy, but in daily driving the stock piece is alot smoother. i was ready to trade in my car before i reverted back to the stock one, and fell in love with the car all over again.
If you want the sound change buy an aftermarket BPV not BOV. My choice would be Forge but if you are not sure go to youtube and watch some videos to see what you like. If you are doing it for performance then dont waste your money or time, the stock works fine.
