ok i was wondering what exactly this air pump does? does it have anything to do with the cat converter in my old exhaust because i got a new custom exhaust put on and we cut the line that was going to the cat now it just sits there and doesn't do anything. so i was wondering if i can take the air pump off of my engine. it says do not remove air pump on the pump but if it has anything to do with the cat then its not doing anything anymore...sorry kinda new to this still.

thanks

 

The air pump on a S5 (89-91) non turbo provides air for the cat converters, as well as for the VDI and aux port operation.

removing it will kill the VDI and Aux ports, reducing mid and top end horsepower