What is VVIS and how does it work?

[MAM] VVIS stands for "Variable Volume Induction System," and is explained in the second NSX book on pages 26-29. The VVIS optimizes the air intake for different rpm ranges. For more low- and mid-range power, these butterfly valves remain closed (they look like paddles in the intake system, one paddle per runner). The book says the VVIS is activated by manifold vacuum above 4,800 rpm. By opening the valves, the intake air has acess to a second plenum which provides more "space" for the air- sort of like the Porsche Varioram system.

[BC] A note about the NSX variable induction butterfly valves: You can make it run at max volume all the time by disconnecting the hose to the solenoid and capping it, however I didn’t notice any difference in performance when I did this (supposedly I should get less low end torque). Makes you wonder if the variable induction is of any real use or if they included it as a techno-gimmick.

Technical Information