Tech:Engine/A Series/TVIS
What is TVIS?
TVIS - (Toyota Variable Intake System) is a design to help the engine keep maximum torque throughout the rev range. The Engine has a plate (referred to as a "TVIS Plate") that sits in-between the intake manifold and the head. The TVIS plate has 2 runners for each cylinder, the theory behind it is that only one intake runner per cylinder is open at low revs (this is to keep the intake velocity up). Somwhere around 4400RPM - 4500RPM onwards the ecu triggers the VSV (Vacuum Switching Valve) to open up, which in turn utilises the engine vacuum to open the other intake runners in the TVIS plate. This way the engine is getting more air as its under a greater load.
TVIS Plate
TVIS VSV (Vacuum Switching Valve)
TVIS Plate Against Head
Intake Runners
Article by Medicine_Man
Back to A Series Engines
Back to Main Page