Variable Intake System
On the KV6 inlet manifold, or plenum sits two motorised valves, one operates the balance valve that controls the two plenum chambers. The other is the power valve, this operates 6 off butterflies within the plenum itself.
That's what gives the KV6 a kick at around 3.5k and more at over 6k, it's been so long since I have driven my 180 I can't remember