Originally Posted by Megan370z

Your statement is wrong.

the same exhaust heat is being thrown down the exhaust. it does not matter cats or not ... I shouldn't have added in my statement about heat because its wrong... because you cannot produce more heat after the combustion is done .... that 600F+ you are talking about is just at that location the heat will generally be (as per what you are saying) at 600F in the cats .. if you have a cats at the Y-pipe (xyz y-pipe) the heat will be less.. because its farther down the stream ....