NB CAT Question

[gabkwong]

What is/are the option(s) for replacing the CAT on my 99? My CAT just died (135K) and is in the market for one. Is/are there any CAT(s) that I should consider besides the OEM and the Flying Miata, they are around $300 from MazdaSpeed and Flying Miata respectively?

Thanks,

[sunlokyee]

I had a CEL from bad cat a month ago. The CEL went away after I changed out the stock midpipe for the roadstersport midpipe with high flow cat and resonator. The midpipe was also 300 dollars.

[jeff_man]

the nb cat is welded to the midpipe, think you might have to cut and re-weld or get a hole new midpipe

[gabkwong]

I had a CEL from bad cat a month ago. The CEL went away after I changed out the stock midpipe for the roadstersport midpipe with high flow cat and resonator. The midpipe was also 300 dollars.

I see this in Good-Win Racing. Is this a direct "plug and play" and have the spot for the O2 sensor? This is a 2.5" pipe. Does is bolt in OK to the rest of the system? Do you notice any gain in HP b/o the bigger pipe and high-flow CAT?

Thanks,
Gab

[jeff_man]

i'm running the RoadsterSport on my car, i can't tell you hp gain since i ran it with stock hearer and a super high flow cat back. but when i did the mp62 and jr header i know it helped out. your most gain with be if you have a non-oem header and catback. most people are running a stock midpipe with after market header and exhaust and not getting the most gain they can. but if it's a rsport or stock i would go rsport.

[sunlokyee]

yea the roadstersport midpipe has the O2 Sensor hole after the cat and before the resonator, it's a simple bolt-on install to replace the oem midpipe. I donno about how much gain though since I installed an exhaust at the same time.

heres a pic of the midpipe before my install:

[gabkwong]

Thanks! I just ordered the Raodstersport mid-pipe/CAT from Good-Win. It was a toss up between the Roadstersport and FM. It comes down to the FM does not fit perfectly with a small exhaust leak (mentioned in the FM site).

[CarCar]

I am very happy with my Roadster midpipe. My stock midpipe broke at the resonator after I installed JR header and RB dual exhaust. Was easy install, very good fitment and not a bad price for the whole. The O2 sensor after the cat leaves a little extra wiring you have to tie and tuck up away but easy enough. It does sound a little dry and raspy before it gets completely warmed up though.