Hi, Im installing a flowmaster catback and and edelbrock TES system and my original catalytic converter wasnt coming off because of the air pipe coming out of it. We cut it off of the cat so we could get it out with plyers or by crushing it and then pulling it out. But it was so clamped so tight that it indented through both pipes where it inserted out of the cat. Two questions, what exactly is it? and Do I really need it?

 

That is your AIR air tube. It diverts air to the cat so that the extra 02 can complete the combustion in the cat. It is necessary for long term cat life.

 

I always wondered about that last comment. If its necessary, how come so many car's don't have them? Is it just necessary on the 3rdgens because they don't have any other emissions provisions? Just wondering because my '93 Beretta GTZ didn't have one and a lot of other cars I've seen don't have a smog pump, let alone add'l air going into the cat.

 

There are different types of cats (2 way, 3 way ect) that don't all need the AIR system. There are many other factors as well for AIR implementation. Such things as, open loop AF ratios, engine design ect ect.

 

I ran mine for 2 years w/o A.I.R. I hooked it back up before I went through the emissions test again. It passed with flying colors.

I don't really buy into the cat-longevity arguement with regard to no-A.I.R. The A.I.R. is there to assist the cat in doing its job, that's all.

A cat that doesn't have an A.I.R. tube isn't a legal replacement on 3rd gen cars. One that has it but isn't hooked up isn't going to work as well.

 

I am starting not to believe it either. I have had my AIR capped for awhile now and it has yet to clog. A poor tune with a constant rich condition can clog a capped 3 way cat eventually though. Most IC engine books will maintain this as well. However, as five7 mentioned, it doesn't always seem to be the end result.