[soxfan143]

I think that vent on the side is for the air to pass through when the throttle plates close at high speeds. That way the high pressure air can pass through without pushing on the throttle plate or push the intake hose off when high pressure air just slams into it. The air has to have somewhere to go. No? Also When the air is blasting in there and the plate closes it will jusy over flow back out through where it came. With that vent it constantly has fresh air blowing past the filter. This way the car will always have crisp throttle response.