Variable Induction System: Description and Operation

Intake Air Bypass (IAB) Control System
Two air intake paths are provided in the intake manifold to allow the selection of the intake path most favorable for a given engine speed.
Optimum performance at any rpm is achieved by closing and opening the Intake Air Bypass (IAB) valves. High torque at low rpm is achieved when the IAB valves are closed, whereas high power at high rpm is achieved when the IAB valves are opened.