It comes through the vent and around the edges on the newer bikes. on the older ones, like my 03 it came with a sealed airbox that got its air entirely from the left side scoop through the frame. if you use a solid 03 airbox you could try to pressurize it, but our xbs are better for 0-80mph, and ram air is really a bit better for higher speeds, for the amount that it actually affects performance anyway. It could be an ok project, I even have an extra frame snorkel if you want it. I still think youd be better off just keeping it open to let the airflow through.