I got a question about having 2 Cats on 05 zx4 st..!!!.

[wakeupandbord]

I was under my car the other day and Im almost positive there is a second cat on my car and was wondering if I could remove the one closer to the exhaust manifold and only have one if I get an exhuast kit.? Would it help to put a flex pipe in place of one of the cats and put a high flow one in place of the other? I'm just not sure if screwing with both cats will hurt the car because most 4 bangers need some back pressure and this might eliminate too much.

Please get back to me ASAP. Thanks. I really need to talk to some people who know what their talking about and Ford would probably laught in my face if I called them up and asked this..pfffhhhhh. Dealerships..

[Sponsor]

[wickedgreyzx3]

no car needs back pressure,

anyways on newer cars back pressure is almost non existent to begin with

[05-ST]

I recently got an exhaust done to my 05 ST. It is illegal to touch either cat unless the car is 5 years old or has 80k on it, that is what I was told. People still do it, they take one cat off. If you do mess with one of them, leave the one closest to the flex pipe alone!

[firemanfrank]

My St is staying legal, so my custom 2 1/4" exhaust is of a "cat-back" design.

Both cat's are untouched ...

[strung]

i got it easy here in oregon....no inspections. i have the focus sport cat back wich deletes the second cat. even though we dont have inspections im still keeping my primary cat.(wich means no header in my future lol)

[wakeupandbord]

We dont have emission tests in Michigan either or at least i've never heard of doing it. So if I upgrade my exhaust and dont care about it being illegal should I take out the second cat and just buy a cat-back system that continues after the cat so I save money on the cat and im only paying for piping and high flo muffler? Another question is should buy a high flo muffler or not for the second one or would it just be more restrictive than not having a second cat at all? A third choice is have is to buy an exhuast system INCLUDING the cat and the rest of the goodies (piping,high-flo cat,muffler), or is it bad to screw with that second cat closest to the exhaust manny?