Cats and wrapping

[TGX4776]

So when I replace my exhaust system, Do I need one or two hi flow cats?

Also I know wrapping the headers helps so why not wrap the whole system?

[StatGSR]

depending on your emissions you dont need any..... but no, the cat is after the header collector on the EJs so you only need one.

after the header, there is no need. The headers are the first place the exhaust meets. aftermarket headers made out of SS lose the heat they are exposed to (from the exhaust inside them) much faster than large oem cast pieces. you want to retain heat in your exhaust system because it increases the exhaust velocity, but its really only at the beginning of the system where it is most helpful.

[TGX4776]

ok, cause the stock system has two so I didn't know if it was nessicary.

[phi11]

yes, two are stock.

http://www.youtube.com/watch?v=BjfbS_Kj-J0

edit: don't wrap you're cats.

[decke48]

depends on state, if your state checks emission or not. or if they do visual check on cats. if they do visual. you need 2, if not you can get away with one

[TGX4776]

Lol. well my guy in WV half asses the checks. which is ok because I am anal about maintenance. But they never check emissions. SO I guess I will get away with it. sweet.

[ouch1011]

Legally speaking, you need 2 in the stock configuration. But if you do headers, the car won't be emissions complient anyway. So... I would suggest at least 1 though. The difference in performance between 1 good hfc and none is not noticable, but running with no cats makes the car smell really bad.

[TGX4776]

how does doing the headers make it non compliant?