Cats REALLY?

[Scorpius]

Had my cats and o2 sensors replaced somewhere near the 200k mark give or take 10k. have 264,000 on her now. 2004, 330i zhp. throwing P0420 and P0430 codes. Indie shop telling me $2200 cats. Are you kidding me?

What else could it be? possible burning a lil oil from ccv fouled the system and I can somehow clean it out? I do have a good six months before my next emissions, but with my wife getting a new car this one has to run at least to 305k :-) (or further lol)

[Scorpius]

Any thoughts?

[yura]

I'd check local junkyards for 330's that you can pull cats from. Gotta be cheaper than $2.2k.

[BMWCurves]

Sorry, I don't know much at all about the exhaust system in our cars. I'm sure others that know more will chime in.

[Scorpius]

Picked up some cataclean will throw $15 at it hope it cleans up the system.

[GotZHP]

You dont have your location posted but can you run catless? thats always an option.

You could always get a high flow cat as well and bring it to your local muffler shop to fab up.

[Scorpius]

You dont have your location posted but can you run catless? thats always an option.

You could always get a high flow cat as well and bring it to your local muffler shop to fab up.

Atlanta. Doubt I can do that and pass emissions

[GotZHP]

o emissions. How strict are they there? Hows it compare to Cali?

[Aeternalis]

If you do need to replace parts on the cheap, you might be able to go this route:

$325.00 - exhaust manifolds (headers): http://www.europartsonline.com/bimmerbrakes-ss-m54b25-m54b30-v1-performance-headers/
$142.16 - catalytic converters (two each, 2" inlet/outlet): http://www.summitracing.com/parts/mpe-53004/overview/

You could then have an exhaust shop replace the first resonator in the system with a catalytic converter on each primary pipe.

25089

You could then have them weld in an O2 sensor bung after each cat.

You'd then need to lengthen the wires from each of the downstream O2 sensors and insert the sensors in the new bungs.

The downstream O2 sensor in the OBD-2 system exists solely to measure the emissions after the cat. That's it; nothing else. If it sees fewer emissions than what's read by the primary O2 sensor, everything's peachy.

Anyway, this is all hypothetical. I've not done this myself nor do I have any measurements of the exhaust system to say for sure whether or not it's actually feasible, but on the surface it seems much cheaper than a $2200 repair. The OEM parts themselves are around $900 each.

[Sockethead]

The problem is that the cats are part of the exhaust manifolds which makes any option, even OEM replacement very expensive. Used ones would be the cheapest route. Perhaps you can find a set on one of the forums where someone is selling due to header installation. That would be a safer bet than a junkyard...

[az3579]

The problem is that the cats are part of the exhaust manifolds which makes any option, even OEM replacement very expensive. Used ones would be the cheapest route. Perhaps you can find a set on one of the forums where someone is selling due to header installation. That would be a safer bet than a junkyard...
With the amount he drives, I think new is the best option. Used ones are a lot closer to their own "sell by" date. It would be a waste of labor $$ to install a used set, IMO.

At over 30k a year, the miles add up QUICKLY!

Sent from my LG V10 on Tapatalk

[Scorpius]

Where is cheapest place to get these new? And how hard if a diy is this or is it just better to pay someone?

[Aeternalis]

Where is cheapest place to get these new? And how hard if a diy is this or is it just better to pay someone?
GetBMWParts.com has 18407514502 and 18407514503 for $744.37 apiece.

[E_Rak]

Do they do emissions sniffers in your state? If not, just go catless and tune with an o2 sim to keep the OBD gods happy.

[Scorpius]

They usually just do the connection to my reader connection and a gas cap test. Nothing up exhaust.
I am Leary of passing the system though doesn't it work to keep fuel mix correctly? Besides I'd think labor is same regardless maybe a tad bit cheaper for parts.

[Sockethead]

The first set of O2 sensors do the mixture. The second set monitor the Cats. It's the second set you'd be bypassing.
If the existing cats aren't affecting performance (clogged) you could just leave them in there