CATs and the difference

BluMicaR

Member
:
2007 Mazdaspeed3
So in buying an aftermarket or Mazdaspeed exhaust (CAT-back or turbo-back), will getting additional mufflers (i.e. the CPE exhaust) make any relevant performance difference? Additionally, what are drawbacks to eliminating a cat vs getting a high-flow cat? I understand there are two cats on the MZSP3. If I eliminate both of these, I understand there is a noticeable performance difference. What about sound, which brings me back to the muffler question.

If I got, for example, a CPE turbo-back, with both muffler options, but no cat anywhere in the stream, how loud would it be? Would either of those mufflers defeat the purpose of removing a cat, i.e. add restriction I was trying to avoid in the first place? In addition to noise concerns, what other things do I need to consider if planning on going cat-less?

I'm trying to keep a nice tuned sound, without having a ricer-whine, or the loud, obnoxious churtle. I like 'knowledge's set up with the CPE and high-flow cat with one 12" muffler, it sounds pretty tight. I'm new to tuning 4 cyls, so I'm looking to understand what is going to do what.
 
It will be load as hell if you take out both cats. And in most States illegal too. When takeing out the cat you will gain power in the upper rpms but lose torqe in the lowend. Well that's how it works on N/A cars. I would suggest going with highflow cats. Keep it legal and smog friendly!
 
well that dpends if in cali. cant touch or take out your cats till 80,000 miles illegal to change it befor ethen. If ti goes bad before 50,000 delaer has to replace period. (there resonsible for smog legal stuff at some fo them period warranty or not.

PLus some cats today you onlyloose 1-2 hp in na cars.
 
i would go with a turbo back with one high flow cat and then mufflers. i have a speed 6 and its louder but not to loud and it passed state inspection here in RI.
 
i would go with a turbo back with one high flow cat and then mufflers. i have a speed 6 and its louder but not to loud and it passed state inspection here in RI.


I'm in Indiana, I don't think we even have laws... LMAO.

But I don't want it loud, I want a nice purr that responds with growled warnings under throttle. I am to take it to go one muffler and one high-flow cat with a turbo-back, then, for what I'm looking for?

I didn't realize high-flow cats were so efficient and didn't cause a giant drop in gains!

Thanks for responses and info so far, I really appreciate it!
 

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