I just got a stock air box, need to smog it in California. I didn't get all the hoses and there is one extra hose connection on the side of the air box housing. It look s to me to be a pressure vent to outside air but the manual pictures don't really confirm that clearly to me. Anyone out there fill me in on the proper set up??

 

The opening on the driver's side of the box is indeed for air relief. Normally, a hose attaches to it that runs underneath the air box and vents to atmosphere. It won't effect your emissions but a pain-in-the-*** smog tech might question the opening.