Timmy121

So my drivers side catalytic converter is going bad and in need of a new one but figured i should just replace them all because of age anyway. Dealer quoted me $4,008.63 for both sides and i don't like that price. Hate to ask but any aftermarket that will work just as good or better? bolt on preferred but welding is fine.

Thank you all in advance!

rilonprime

Primary or secondary cat? Our cars have 4 in total. You could just delete it and reap some power gains

Fantomas

Need a new one because it's throwing a cat efficiency code or because it's clogged and the car is misfiring badly?

Benzaddict32

I recently had my primary cats replaced with a pair of magnaflow universal cats. My passenger side cat had been rattling for a few months and I had finally had enough. I believe I paid less than a $100 for the pair. It’s been about 2,500 miles since and so far so good.

alboogiee

I would suggest to start with replacing your post cat o2 sensor(s).

Timmy121

Not sure but i got the code P0422 - power train - Main Catalyst Efficiency Below Threshold (bank 1)

I think its from changing my headers because it was after that and my tune when it started, i get a nice pop/popping sound now in my exhaust when i downshift or hit 4k+ RPM and let off the gas (blow back?) sounds nice!

Timmy121

throwing a cat efficiency code. think its from changing my headers and Dyno tune

Timmy121

I don't have any rattling sounds or anything like that, starting to wonder if its just my Tune and new headers causing the code but yeah that's a really nice price! i was looking at the magnaflow, bolt on or welding tho?

Timmy121

That would be a good start! would you happen to know the part numbers?

Timmy121

If i were to remove both primary Cats would i pass emissions (Maryland)? and how could i keep the car from giving me check engine light with the cats gone?

Fantomas

Before you waste a ton of money on unnecessary parts I would suggest that you invest in some oxygen sensor spacers for your secondary o2 sensors. They are about 6 bucks a piece and are my go-to method when dealing with cat efficiency codes.

Timmy121

Could you link me to spacers? i founds tons but not sure what would work with the C55? all the same sizes?

Thanks

Fantomas

Most oxygen sensors are the same, 18x1.5mm.

I'm not sure about clearance on the C55 but these ought to do it.
https://www.ebay.com/itm/O2-oxygen-s...ss!97080!US!-1

Timmy121

Great! i picked these up from advance for $8.59. says spark plug fouler but guy told me its the same thing? gonna try to get them in this week

Thanks!

AtlasMG

You said you changed your headers with OEM or performance because if you got performance headers your tuner should have tuned the code out because I plan on getting Kleemann headers and they delete the primary cats and with a tune the check engine light goes away.