MM2death has given you the pic.
If your one isn't making any noise, then it is probably because you have the standard air box.
When you have a pod filter, it is very free flowing and you can hear all sorts of induction noises.
also, when the bov vents, you will hear a sshhhhh sort of sound.. different to the aftermarket psshhtt sound.
the standard bov makes more like a hissing sound.
IF your bov is removed and all holes are blocked off, and you put a pod filter on, when you back off from the accelerator, you will hear a fluttering sound.. like ch ch ch ch ch ch
Hope this helps.
And there are a fair few turbo cars (engines) that don't have bovs as standard..
here are a few.
Cordia turbo.
CA18DET engined cars.
VL Turbo
That's a few off the top of my head.