The ACIS controls a butterfly inside the main section of the intake manifold(under the plate with 6 srews) that will shut at a certain rpm seperating the manifold in 2. It is controled by a vsv and a vaccuum canister that is controled by the ecu. I don't remember the right rpm though. But what is does is keeps the air from each side of the y-pipe seperate and flowing into 3 runners each instead of a open chamber of 6 runners. I think the whole purpose is to reduce turbulance in the air flow being sucked in. This is why the turbo does not have one since it is forced induction and not natural aspiration.
|