ProtegeES

who sells a test pipe for our cars? Are there any O2 sensors after the 2nd cat?

mazdamp3_18

i removed my 2nd cat and resonator.... i had it done at a muffler shop... but if you want a test pipe then get the bosal exhaust its called the Federal Version.. it has a pipe that eliminates the 2nd cat and it dosent cost more than the regular california exh... but i had mine custom done b/c i wanted to keep my Racing beat muffler...

ProtegeES

did you notice more power?

pkc

removing the secondary cat is NOT going to give you any appreciable power gains.... as has been stated time-and-time-again about our cars, it's the crappy header/primary cat that is the major limiting factor. that second cat is only for us to meet LEV/ULEV [whichever one... i can't remember] and it's removal would only account for an extra 1-2HP if that.

as for the bosal... get the federal. i did. i removed the second cat. the exhaust itsself did not give astronomical gains, but it does REALLY help out with throttle response, which if you think about it, is just as important. the faster you can get into your power band, the faster you can apply it....

mazdamp3_18

i didnt really notice much but throttle responce did improve a lot.. and it did make it louder too... soon i will have to get a high flow resonator b/c im going to have a header soon and having only a straight pipe with no cats and just the muffler is going to be LOUD