[Ravq]

They are for the positive crankcase ventilation system. They help to keep the intake tract clean of any excess blow by. No real performance out of them. It's mostly cosmetic, but what it does is vent the oil fumes into the atmosphere. Your engine usually takes those oil fumes and recycles them into the incoming intake charge, so you end up burning those oil vapors. But you'd rather have clean, fresh air going into your engine so you vent the oil vapors.