Rotory1990

Hi, My name is Xavier, I'm 19 and just got my third car which is a 1986 Rx7 and im Proud of it even though im strapped for cash and have alot of work to do on it. Just finished replacing the brake lines and did a simple tune up (new spark plugs, air filter, oil change, bled the brakes and such) As of right now i do have One question im pretty stumped on, What is that piping that sprouts from the catalytic converter? and seems to split off into the engine? some kind of emission thing? anyways, Responses are much appreciated