Induction System

WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

A dual-stage variable intake manifold is achieved through the use of a variable intake manifold (VIM) valve. The engine control module (ECM) controlled valve changes the plenum volume available for resonance tuning of the inlet flow path. With the VIM valve shut the intake manifold is using dual plane flow with the cylinders feeding from 2 separate plenums. In this mode the system boosts cylinder charging in the low to mid speed range. At higher engine speeds the VIM valve opens creating a single plane flow with the cylinders all feeding from a common large plenum. In this mode the system boosts charging in the high speed range. An electronically controlled throttle (ETC), through the ECM, coordinates the input from the driver with various control components.