i may be wrong, but on a stock intake pipe, i believe there is a box on the side of the pipe that goes through the section where that elbow is, from my observation it looks like a resonator similar to the ones ive seen on wrx's, i know that on the wrx, when removed they allow better airflow and you can hear your stock gate and bov much better , their main purpose on a wrx, was to basically do something (i dont know what) to the airflow to make the car quieter, at the expense of hp, and i think it is the same setup on the intake pipe of my n/a skyline