All X3 models with the N52 engines incorporate the 3-stage variable intake manifold called DISA; in this system, a number of valves within the intake manifold are controlled by electric motors and gears. These actuators are controlled by engine control module signals in the form of pulse width modulation and each valve has an ability to be either opened or closed. The so-called intake manifold runners' length have been switched to provide torque over the range of engine speeds, two DISA valves and one overflow pipe. When it comes to idle and low engine speed operating range, ordinarily both DISA valves are closed whereby air intake is through a throttle valve into a resonance pipe then divided to each cylinder in large quantity of air mass When operating in the medium engine speed range, one of the DISA valves is open and at the closing of intake valve there are pressure peaks which causes the intake air to resonate to the next cylinder in the firing order and thus improving its charge In engine speeds where ZEV is high both DISA valves are open and the intake air mass is directed through resonance, overflow, and manifold runners during the pressure peaks before the closing of the intake valves.