Thanks for the reply bud - I was not trying to be a pain. I recently had to jump through hoops with the EPA over this stuff because I have an aftermarket catted pipe (2 total) instead of the stock 4 on one of the stangs.95GTAODE said:Ah Hissin, you're killing me!
Don't take this as gospel, but I've read that the "pre" cats are one ways and that the second is a two way. The pre's are there because they heat up faster and reduce emissions while the car is cold. After market pipes use 2 3-way cats.
I have read so many sources of info and I never saw anything definitive. When dealing with this stuff, I had wanted to know exactly what was inside each cat. I thought the same as you, but then one decent source mentioned that the second cat was a 3-way, which surprised me and made me wonder why the first cat was needed (I also thought it was a one way and a two way, as tech was not as good back in the day).
I do appreciate your info.