I am looking at a 02 s4 with bad cats?

[derek2079]

Is it possible for catalytic converters to go bad? Is there a simple way to fix them? I didnt scan the codes but the car is a real good deal because the owner states it has 2 bad cats. So my question is how do I fix bad cats? How much money am I looking at? He said they just went bad at 150k miles he never messed with the exhaust or anything.

[big_jerm]

Bad cats will make the car run really hot and have very little power. I'm not sure what would cause them to fail at 150 though, there could be an underlying issue that could be causing the problem.


You could buy ssac downpipes for $300 with or without cats. if you went no cats then either code out the rear 02s, or use the spark plug defouler method to not throw a code and pass emissions. if you have the stock exhaust, catless will be a bit louder but I can't imagine it would make it crazy loud.

could also go catless and then stage 2 tune for a nice bump in power!


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[Bordom]

Yes.

The fix? Replace it. Get aftermarket 3-way cats welded in for $3-500, go new OEM for +$2k, or go catless with some O2 spacers for $300.

Everything graciously mispelled by Android

[derek2079]

Doesn't seem to bad. Car is definitely was in limp mode when I took it for a spin around the block. I hope the guy holds the car for me. Can someone link me to the cheapest thing to have welded on in place of my current cats?

[themadscientist]

Cheapest thing? Test pipes and rear o2 spacers.

[derek2079]

will it have a cel with a test pipe? In my state there cant be a cel.

[derek2079]

Do I need two of these? Both cats are bad. http://www.ebay.com/itm/Audi-A4-B5-B...FShU7H&vxp=mtr

[Corradovolksb]

Those are for cars with a 1.8t. You can install new Downpipes and get a tune that deletes your rear o2s and disables your cat diag.

[LINDW4LL]

will it have a cel with a test pipe? In my state there cant be a cel.

Aftermarket downpipes are your best bet. They're at the top of the list as far as performance mods for the car anyway so you knock out two birds with one stone.

From there, you can either code out the rear o2s in your tune or use o2 sensor spacers to preent a CEL, OR preferably purchase some High flow cats and have them welded into the midpipes. I'll be going with some Magnaflow 200 cell metallic cats, which are only about $160 for the pair.

[derek2079]

Aftermarket downpipes are your best bet. They're at the top of the list as far as performance mods for the car anyway so you knock out two birds with one stone.

From there, you can either code out the rear o2s in your tune or use o2 sensor spacers to preent a CEL, OR preferably purchase some High flow cats and have them welded into the midpipes. I'll be going with some Magnaflow 200 cell metallic cats, which are only about $160 for the pair.

Where can I find those?

[goalieman24]

Where can you find what?? He mentioned about 5 different things.

You should fully scan the car before going any further.

[JVD]

Also have to ask yourself...

Why would the owner sell the car with bad cats if that's ALL that's wrong? He's losing out on a bunch of money.

[derek2079]

You sound paranoid JVD. He has a lot of reasons to sell this car being the fact that he just bought a new one and owned this for 11.

[JVD]

You sound paranoid JVD. He has a lot of reasons to sell this car being the fact that he just bought a new one and owned this for 11.

Sound logic.

Carry on.

[MagnaFlow]

We offer both universal, and direct replacement catalytic converter units for 02 S4s. The most inexpensive option would be the universal standard-grade cats (part# 99005HM), which start at ~$110 each. If you have any questions, please feel free to shoot us a PM.

[derek2079]

No longer looking.

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