http://www.mossmini.com/Shop/ViewPro...eIndexID=86305

What exactly is this and what does it do? The description was a little vague. I know it's not a BOV but it talks about the sounds turbo cars make. I'm not very familiar with these kind of things.

Normally the stock diverter valve (bov) vents to the intake side of the turbo. The addapter you linked blocks the normal passage into the inlet side of the turbo and forces the DV to vent through holes in the side. It basically makes the stock DV a vent to atmosphere. It's for noise only.

You'll also enjoy the check engine light's you'll get for the $80 price

Both statements above are true. Save your money and get a real valve.

Alright, thanks guys. I don't understand why companies try and sell stuff like that....

Anyway, I'm not sure i'd want a BOV because I heard they can cause a lot of problems. They sure sound cool though...

The same effect can be made basically with an open air intake. You will hear the DV venting and hear the turbo spool a little.

Also, don't forget you will effectively run richer during each period the valve is open. This is because you are releasing metered air without the ECU being aware. I can only imagine this causing a CEL due to Lambda fluctuating excessively.

Oddly enough I've recently taken my Greddy BOV recirc tube off to see how the car acted. No code. Even after days of driving and I didnt see any super-rich conditions on my AFR. I put it back on but no tantrums from the car. I do run a resistor to trick comp into thinking stock DV is present.