What is a Butterfly Valve?????? Im a newbie so i just need some advice! Thanx

 

Its the set to steel plates that rotate 90 degrees to open and let more air into your engine. Below ~3800 rpm your intake uses long, narrow runners to speed airflow and boost low end power. Above ~3800 the valves flip open so the engine can gulp as much air as possible at higher rpms. Its only on the Type S. If the motor that controls it fails like mine did, your car will be totally gutless about 4k.