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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
thanks (wiggle)
K&N Typhoon Air Intake
- Thread starter Khasmordan
- Start date
thanks (wiggle)
Khasmordan
Member
- :
- MS3 True Red
I feel like such a noob, what does BPV stand for?
No.
Khasmordan
Member
- :
- MS3 True Red
What is the Bypass Valve for? This is my first car and a lot of the terminology is new too me.
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- 2007 Mazdaspeed 6 Sport
When your turbo is making boost, it will continue to make boost for a slight moment after the engine revs slow down. With the engine revs slowing, it cannot take the volume of boost that is being pushed to it. As the volume increases, the pressure increases. The bypass valve (BPV) opens at a specified pressure and recirculates that boosted air into the intake, post Mass-Airflow Sensor (MAF).
In short, it is a method of adding efficiency to our turbo setup.
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- 2007 MS3
Additional info here.
It isn`t just a matter of efficiency. It can be argued that a BPV is more efficient than a BOV (blow off valve, which dumps the extra air to the atmosphere), but that isn`t the main point. Under pressure, you have a greater volume of air. When you lift off the gas, the ECU closes the throttle and reduces fuel. If you still have that high volume of air trying to go through the engine without the matching fuel, very bad things can happen.
So the valve is also (arguably primarily) a safety feature to help keep your engine in one piece.
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- 2007 Mazdaspeed 6 Sport
Yea, I avoided the term "safety" because I didn't want to start a VTA war. There's enough of them on this site already. 
Thanks for pickin' up the slack!
Thanks for pickin' up the slack!
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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
the corksport intake does not have one either.
Khasmordan
Member
- :
- MS3 True Red
It seems like this is a good idea, better than a BOV. Does the stock 2008 Mazdaspeed 3 GT come with an OEM one or would I have to get my own? Even if I look at getting the PG SRI, PG Turbo Inlet, and a BPV or BOV, thats going to be around 420 bucks, this is getting expensive and fast...
All MS3's come with a stock BPV. Some of us (self included) run modded intakes and exhaust with the stock BPV with excellent results. Some stock BPV's have been shown to leak. Others do not. Mine does not leak. You would need a manual boost gauge or data logging device like Dash Hawk, or at least borrow one to see if your BPV is holding boost. If it is, you don't need to spend the money on a replacement.
If you do decide to replace, aftermarket BPV's also recirculate the air back to the intake, as it should be.
Aftermarket BOV's either vent to air (not so good), or can be configured to recirculate back to the intake. In recirc mode they serve the same purpose as the BPV. Some of them make unique sounds some owners like. Those sounds identify the owner as having a particular brand of BOV. Others (self included) find the extra and different sounds not to our liking and don't care for the attention they draw -- "look at me, look at what I have on my car."
Get a boost gauge or Dash Hawk. Gauge is cheaper. DH more versatile but more expensive. You need that anyway. Spend your money on that and a good intake. K&N makes good stuff. I run a K&N "Air Charger" on my SUV and have K&N short ram type cone filters on two other vehicles.
But for our application, I personally think that a true cold air intake works better (not trying to start another CAI v. SRI war, but must say something on the subject here). Under hood temps can reach 170 degrees easily when sitting in traffic or driving slowly. It takes about 15-20 seconds for the engine to recover from that even when speeding up and getting ambient air coming through the radiator core into the engine bay.
Rule of thumb is that each rise in temp of 10-11 degrees F. robs you of 1% horsepower. So for the first 15-20 seconds, at least, after pulling away from a stop, you can be as much as 70-80 degrees up on temp and down as much as 7-8% on power. That's at least 18 horses at the crank, 15 at the front wheels.
If you do decide to replace, aftermarket BPV's also recirculate the air back to the intake, as it should be.
Aftermarket BOV's either vent to air (not so good), or can be configured to recirculate back to the intake. In recirc mode they serve the same purpose as the BPV. Some of them make unique sounds some owners like. Those sounds identify the owner as having a particular brand of BOV. Others (self included) find the extra and different sounds not to our liking and don't care for the attention they draw -- "look at me, look at what I have on my car."
Get a boost gauge or Dash Hawk. Gauge is cheaper. DH more versatile but more expensive. You need that anyway. Spend your money on that and a good intake. K&N makes good stuff. I run a K&N "Air Charger" on my SUV and have K&N short ram type cone filters on two other vehicles.
But for our application, I personally think that a true cold air intake works better (not trying to start another CAI v. SRI war, but must say something on the subject here). Under hood temps can reach 170 degrees easily when sitting in traffic or driving slowly. It takes about 15-20 seconds for the engine to recover from that even when speeding up and getting ambient air coming through the radiator core into the engine bay.
Rule of thumb is that each rise in temp of 10-11 degrees F. robs you of 1% horsepower. So for the first 15-20 seconds, at least, after pulling away from a stop, you can be as much as 70-80 degrees up on temp and down as much as 7-8% on power. That's at least 18 horses at the crank, 15 at the front wheels.
