Pictures are from the passenger side. What is that pipe that seems to come out from the cat and winds over the y pipe then curves down and up toward the engine? I'm asking because it's the lowest hanging part and often scrapes on bumps. Want to know what it's for and what would happen if it gets damaged. FYI, the first pic is to the left (i.e. rear of the car) than the second pic. Thanks!

 

looks like that hose that comes from the smog pump to the Cat

 

Ok. What's it for? Send fresh air to the cat?

 

it pipes air from the AIR pump to the cat to get it to "light off" faster and start turning all the bad stuff into nice stuff like water vapor and fairy farts sooner after a cold start...

 

It helps get cleaner burning of exhaust in the cat, or something like that. My dad years ago had to get a replacement cat for one of his cars that had that connection on the replacement cat, but on his particular car, he didn't have anywhere at the engine to connect it to, so it was just a dummy connection.

 

Thats for your SMOG. it runs from your headers down to the cat. I cut my cat off my car a month ago and cut that line and bent it so nothing comes out of it. If your state isn't big on emissions, I would delete the cat and the smog pump. Thats what i did with mine. Its fairly easy to do.