I had originally intended to leave my 2010 Speed3 totally stock, but I couldn't resist the allure of 25-35 horsepower from an intake so I picked up a K&N Typhoon kit.
The kit went on with no problems and definitely seems to have added some power. However, the removal of the factory airbox meant I was now hearing things I wasn't before. Specifically, I heard a hissing noise that sounds like the BPV is leaking. It doesn't sound like the sound of a turbo spooling, and when I let off the throttle the hiss transitions smoothly into the "PSSH" sound of the boost being bled off entirely.
After doing some research online I found several reports of the stock BPV leaking, so I got a Forge BPV to replace it. Initially I thought that I'd found a solution, as when I first went out and drove the car I no longer heard the hissing noise, only the turbo spooling. Strangely, though after I'd been driving the car for a little while, the hissing noise came back.
I've since tried a variety of spring/shim combinations on the Forge BPV but I haven't been able to consistently get rid of the hiss. Sometimes it will start at partial throttle and go away if I push the pedal to the floor, but other times it continues even at full throttle.
Perhaps it's too much to ask, but I would expect the BPV to stay closed under even light boost during partial throttle as well as full throttle. Is this the expected behavior or is it impossible to avoid the BPV leaking under part throttle? Does anyone have any ideas about why the behavior seems to change over time? Is the sound what I think it is or am I missing something obvious?
The kit went on with no problems and definitely seems to have added some power. However, the removal of the factory airbox meant I was now hearing things I wasn't before. Specifically, I heard a hissing noise that sounds like the BPV is leaking. It doesn't sound like the sound of a turbo spooling, and when I let off the throttle the hiss transitions smoothly into the "PSSH" sound of the boost being bled off entirely.
After doing some research online I found several reports of the stock BPV leaking, so I got a Forge BPV to replace it. Initially I thought that I'd found a solution, as when I first went out and drove the car I no longer heard the hissing noise, only the turbo spooling. Strangely, though after I'd been driving the car for a little while, the hissing noise came back.
I've since tried a variety of spring/shim combinations on the Forge BPV but I haven't been able to consistently get rid of the hiss. Sometimes it will start at partial throttle and go away if I push the pedal to the floor, but other times it continues even at full throttle.
Perhaps it's too much to ask, but I would expect the BPV to stay closed under even light boost during partial throttle as well as full throttle. Is this the expected behavior or is it impossible to avoid the BPV leaking under part throttle? Does anyone have any ideas about why the behavior seems to change over time? Is the sound what I think it is or am I missing something obvious?
