Audi’s don’t run BOV, they run BPV/DV that recirc blow off back in to turbo inlet pipe. It is metered air and the ECU expects it to be there. With that said, I’ve run a straight Forge 004 BOV before without problems. Some claim that you’ll run rich because the car expects that blow off air to be piped back in.
But, it’s kind of taboo in the Audi world to run a BOV. They call it ricer. So, instead of being flamed on the Audi forums for it, I switched back over to a diverter valve.
My current diverter valve is a Forge 007. If I run the valve in reverse, it sounds a lot like a blow off valve then. It’s rel loud and wooshes between shifts. I switch it around every once in a while to run some data logs and see if it makes any difference.
Obviously, in this video it is not in reverse, so the sound is minimal, at most.