Transient Analysis Flow For Car Intake System

Hi,

I am designing an intake system for a single seater race car (central inlet - plenum - four outlet pipes).

I have the model generated and have run steady state flow simulation (air entering inlet at velocity and dispersing, four outlets set at ambient pressure). The flow works fine but I need to set a time dependant pressure drop from the outlets.

I specified everything as per this video on youtube http://www.youtube.com/watch?v=vIxK6K-XSGU
and specified the dependancies on the outlet lids.

I ran the simulation but the flow trajectory that returned was as if it was just showing the very last air flow path, straight to outlet no.4.

What am I missing to get an animation of the complete cycle

Attached is the excel data for the pressure drops and a picture of the intake system and the flow trajectiry that returned.

SolidworksFlow Simulation