when you remove the hose off the bov to achieve the psssst noise, what do you do with the other end of the pipe, do you plug it up or just leave it open??

 

plug it up, otherwise you could suck something into the turbos

 

just so you don't get confused and plug the wrong hole,

disconnect the bov hose from the air box and set it wherever, and plug up the hole in the air box so dirt or whatever doesn't get in your engine, don't disconnect anything else

 

The perfect cap is an Arrowhead 16 oz. water bottle clear plastic cap. Nice and snug on the airbox nipple.

Warning... the stock BOV is pretty noisy, and I reconnected it after a week.