Variable Dynamic Effect Intake (VDI) System
The VDI system is a variable induction system which changes intake runner length depending on engine RPM. During engine operation, pressure waves are formed in intake air when intake port is closed by rotor revolution. These pressure waves flow toward open intake port, compressing air in intake system.
At lower engine speeds when this pressurization is not needed, VDI valve is closed, causing pressure waves to take longer route through intake system. At higher engine speeds (5200 RPM or greater), VDI valve opens and waves pressurize the intake air through a shorter route, forcing the intake air into combustion chamber. See Fig 1 .