That sound at 44 seconds is the BPV doing its job. It is recycling charge air, the reason it is louder with the pop filter is that the baffles in the stock intake system aren't there to disrupt the sound.
Bpv weird sound help
Hi, since about one month i heard weird sound from my BPV i think. I don't hear it when i roll with the stock air filter. When i roll with my short ram it sound crapy sometime, when ulling about to 3000 rpm and i let the trottle off i hear a sound ( TOUP ) pull again let it off and i hear this ( TOUP ) Sound... like a closing valve or something. I'm an electrotechnician but i don't know why on my car i know nothing i don't know even which component is where! 
also, when hard pulling till 6000rpm release the gas, and i heard a ( FFOUUUIINNN ) sound off my short ram.... pretty sucking, i've film it but it's pretty hard to understand in video. I'll post it althought. Last day i've put back my stock air filter system, i did not heard it again but when i remove the vaccum hose that's going to the SRI i still hear the TOUP sound...
I will try to have better image of my problem. I need help! It pretty suck!
also, when hard pulling till 6000rpm release the gas, and i heard a ( FFOUUUIINNN ) sound off my short ram.... pretty sucking, i've film it but it's pretty hard to understand in video. I'll post it althought. Last day i've put back my stock air filter system, i did not heard it again but when i remove the vaccum hose that's going to the SRI i still hear the TOUP sound... I will try to have better image of my problem. I need help! It pretty suck!
