I got a great deal on a 997S, 3.8 liter air box that I am going to install in my 996. It is a pretty straight forward swap out, but there is one difference in the boxes that I noticed. On the 3.8 box there is a vacuum actuated valve on the smaller hose connection, the small branch of the hose that branches off about halfway up the main hose between the air box and the throttle body. On the older box there is no vacuum valve on the connection.

Does anyone know what the function/purpose of the valve is on the 3.8 box? Can I just leave if disconnected or should I connect it to the vacuum lines. It would seem that this valve closes when there is vacuum and opens as the vacuum drops, unless there is an actuator on the newer cars.

 

Hello I sell a airbox for 997 s, search in the marketplace or write.