With Active Valve Control you get complete control of your factory-equipped exhaust valves in your Audi. The Milltek Active Valve Control System offers a number of features. This system allows you to disable valves open on cold starts, and on the B9 S4 allows the valves to remain open all the time at idle (rather than one open, one closed). This system enables you to open the valves in any mode by pressing the 'ESP' button twice independent of the drive select mode. All these features can be had with a simple installation in the rear of the car and fully integrated with the vehicle CAN-BUS system.
