Variable Intake-Air System (MAZDA6 - 2.3L)
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Variable Intake-Air System (VIS) is designed to produce higher engine torque at lower engine speeds. At engine speeds under 4500 RPM, vacuum is applied to the VIS shutter valve. VIS shutter valve is now closed, elongating the intake manifold runner length. An inertia charge effect is obtained, air intake volume increases and higher torque is produced at low to medium engine speeds. At engine speeds of 4500 RPM or more, VIS is opened. Intake manifold runner length is shortened, increasing performance at higher engine speed.