Variable Induction System: Description and Operation

The air induction system improves engine performance by using the Intake Manifold Runner Control (IMRC) assemblies as follows:

- The intake manifold has two runners per cylinder, feeding each of the intake ports in the cylinder heads.
- The IMRC is integral to the lower intake manifold. The assemblies are located between the upper intake manifold and cylinder heads, providing two air passages for each cylinder.
- One air passage is always available to direct throttle input and the other passage switches from closed to open by means of a valve plate, the intake manifold runner control actuator and cables.
- Below 2800 rpm, this valve plate is closed to improve low speed and cold engine performance.
- Above 3500 rpm, this valve plate opens to improve high speed engine performance.
- The valve plates are opened and closed by the electric actuator and cable assembly, which is controlled by the powertrain control module.