The Official Blown Catalytic Converter Thread

[fitzydude]

I wouldn't do that. I'd remove the 02 sensors and spray some water that way.

I'm in for results Alex.

I'd be willing to try something weird. 117k on my factory cats, they've got to be close to dying with all the weird crap I've thrown at them.

[Loe]

be careful...a long-block isn't inexpensive by any means guys.

[fitzydude]

I still like my idea of sticking an industrial strength roto-rooter up the tail pipe.

[whiped]

be careful...a long-block isn't inexpensive by any means guys.

I hear you, I wouldn't dump anything directly down into the cylinders.

I'm curious if my cats are starting to go, no white puffs or CELs yet but my exhaust note has changed and I have more drone than I used to

Unrelated, if anyone has their OEM cats laying around or are going to toss them out you should totally ship them to me

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If you pulled off the exhaust at the downpipe that might work Alex. Issue is there is a bend in the cats so you wouldn't have direct access without removing them from the headers.

[Loe]

I'd be willing to try something weird. 117k on my factory cats, they've got to be close to dying with all the weird crap I've thrown at them.

you'd be surprised how much abuse they can take though, and even partially clogged the volume is still sufficient for a nice clean 1/4 mile MPH. With that being said, there is something to be said about EGT's (read lower) when you run higher ignition advancement, or at least that's what old hot rodders used to say...something about earlier spark timing in the up-stroke lessens the heat escaping out of the exhaust valves due to the ka-boom event happening sooner and more full (but not to the point of pre-detonation, which creates heat). Not sure how true this is? but I heard it from a guy who knew a guy who purchased a thing in a dark alley...

[derek.kritz]

Doing some logging with my OBD Fusion app. And was looking at the EGT's, and mine range from 1100F at idle to 1500F at wot. Seem about right? Couldn't find any info on it. Note: I run full E85.


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[infinkc]

Friends 2012 s4 at 75K just went out, tuned for the last 10K

[blk18tq]

My drivers side cat went first, then replaced with magna flow, 2 weeks later my motor seized, I think it was all due to running E85 mixture all the time, car run's to hot, I was addicted to race mode for 2yrs..lol!

[FLN2LO]

Well i think i just joined the club today. Did a full throttle run this morning that felt great but i looked back to see a massive smoke screen. First thought was a head gasket but upon further inspection my coolant was good and looking at the oil it wasn't milky (as i've seen on other cars with a head gasket issue). A couple more hard pulls and more giant clouds of white smoke later i noticed some rattling coming from the exhaust. I took a look and on one side only the exhaust tips were coated white with chunks of metal sitting in them and on the ground under the exhaust tips. Clearly the honeycomb of the cat.

So.. here i am at 78,500K and as i understand it there should be an 80k Cat warranty.

Anyone have luck getting warrantied for cats even though their car is chipped?

[miztahsparklez]

Well i think i just joined the club today. Did a full throttle run this morning that felt great but i looked back to see a massive smoke screen. First thought was a head gasket but upon further inspection my coolant was good and looking at the oil it wasn't milky (as i've seen on other cars with a head gasket issue). A couple more hard pulls and more giant clouds of white smoke later i noticed some rattling coming from the exhaust. I took a look and on one side only the exhaust tips were coated white with chunks of metal sitting in them and on the ground under the exhaust tips. Clearly the honeycomb of the cat.

So.. here i am at 78,500K and as i understand it there should be an 80k Cat warranty.

Anyone have luck getting warrantied for cats even though their car is chipped?

Remove the tune. They scan. Will also probably check your PCV


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[DBL R]

I think I joined the club today. Did a long pull. Exhaust is noticeably louder.

[<3S4PLAY]

An update on my car... I was able to get the dealership to replace my passenger cat under warranty, but they definitely tried to put up a fight before finally giving in and replacing it.

I can say that they were not able to detect that I had a tune on my vehicle. I had the ECU and transmission flashed back to stock prior to going in.

Honestly it appears that this is becoming a more common issue with this platform. It'll be interesting to see how this plays out with more people going to the dealership with cat failures.

The dealership that I went to admitted that they had taken in 6 other cars in the past 3 weeks after approving my fix under warranty. The cars included Q5s and A6 with the 3.0t supercharged engine

[xxdunnxx]

An update on my car... I was able to get the dealership to replace my passenger cat under warranty, but they definitely tried to put up a fight before finally giving in and replacing it.

I can say that they were not able to detect that I had a tune on my vehicle. I had the ECU and transmission flashed back to stock prior to going in.

Honestly it appears that this is becoming a more common issue with this platform. It'll be interesting to see how this plays out with more people going to the dealership with cat failures.

The dealership that I went to admitted that they had taken in 6 other cars in the past 3 weeks after approving my fix under warranty. The cars included Q5s and A6 with the 3.0t supercharged engine

So what mods and for how many miles? Dual pulley? How many miles tuned at what levels?

[cspcrx]

Were the others cars tuned, did they say?

[Rodizzle]

[QUOTE= did they give u and shit cause u had the aftermarket exhaust? And what dealership in the bayarea ?


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[<3S4PLAY]

So what mods and for how many miles? Dual pulley? How many miles tuned at what levels?

I was 034 stg 1 for approximately 10k miles and then 034 stg 2 for approximately 30k miles, before the cats failed at 63k miles

- - - Updated - - -

Were the others cars tuned, did they say?

The Q5's and A6's that were at the dealership with failed cats were all stock

[<3S4PLAY]

[QUOTE=Rodizzle;12502057][QUOTE= did they give u and shit cause u had the aftermarket exhaust? And what dealership in the bayarea ?


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I left the exhaust on the car and they tried to blame the "smell" from that. I explained to them that I personally installed the exhaust myself and it had been on the car for over 50k miles and that nothing had changed since.

Dealer tried every excuse to not want to replace the cats. The smell was so bad that I would almost pass out during a 30 minute drive. They said that's normal with an aftermarket exhaust. They then went on to say that the smell is because I had an exhaust leak somewhere downstream way past the 02 sensors, and that the CEL was on because the o2 sensor was detecting the exhaust leak.I ended up having to draw a diagram of the exhaust system and argue with the "master tech" and service advisor on how and where the o2 sensors function before they agreed to fix the issue.

This was at Concord Audi, the dealership I purchased the vehicle from.

After the vehicle was fixed, they asked if I tried to hollow out the cat, because the passenger side was completely gutted. If you have seen the shape of the catalytic converter you would know that it's almost impossible to hollow out perfectly. The techs didn't bother checking for pieces of cat material in the exhaust. When I got home I took apart the whole exhaust and shook out a bunch of moon rocks from the mufflers and midpipe

[miztahsparklez]

Due to Cali laws, you are good to go on cats up to 80k. I just passed 80k and yet again I pulled a chunk out of me exhaust lol. Sigh.



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[cspcrx]

hard for them to blame exhausts and tunes when stock cars are having issues. All about saving money! They are already in enough heat with the EPA you would think they would not want to draw extra attention with stuff like this.

[Mt_S4]

I still like my idea of sticking an industrial strength roto-rooter up the tail pipe.

I'm looking to try gutting my cats without removing them of the car, the roto-rooter seems to be the perfect tool since you can put different ''drill bit'' on it.

Anyone have tried it ?

[Rodizzle]

I'm looking to try gutting my cats without removing them of the car, the roto-rooter seems to be the perfect tool since you can put different ''drill bit'' on it.

Anyone have tried it ?

Call me crazy , I thought the same thing . Sounds like it might just work . Drop the down pipe and rent a rotor rooter from homedepot for 40 buck .


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[cspcrx]

They may not be able to apply enough torque to brake up the catalyst.

[Rodizzle]

They may not be able to apply enough torque to brake up the catalyst.

Trust me that shit breaks everything !!! broke my plumbing pipes. Made my stuck turd even worse of a problem


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[Gtotherock]

Looking into aftermarket test pipes. I'm in Florida, and no one cares about running cat less here. Any brands that you guys have heard good things about or recommend? I don't want high flow cats but rather test pipes. I've looked at JHM, until I heard through some friends that their test pipes aren't very good. But maybe those friends are morons!?
Any info, of different brands of test pipes, is much appreciated.
Thanks!


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[GandalfTheIbis]

Tampa Autosports, formerly Crown Motorsport via Evan Doel can provide you with test pipes. That's what many in the community are running without issue.

[SN0101101001]

Tampa Autosports, formerly Crown Motorsport via Evan Doel can provide you with test pipes. That's what many in the community are running without issue.

I was planning on obtaining these as well. Do they need to be ceramically coated?

[Gtotherock]

Thanks GandalfThelbis
Only a few hours away.


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[AudBoost]

I was planning on obtaining these as well. Do they need to be ceramically coated?

They don't need to be, but Evan can have them coated upon request.

[Loe]

another vote for Evan @ Tampa Autosports, the pipes are top-notch

[Gtotherock]

Will having an exhaust shop gut my stock cats, act as a test/race pipe in terms of power gains? I live in Florida, they don’t check cars for emissions here. Thinking of hitting stock cats and running straight pipes to my 034 x pipe and straight pipes all the way to some Milltek exhaust 2to1 100 mm tips. And yes, I know this will be very loud!


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[Gtotherock]

Gutting stock cats*
Damn you Autocorrect!!


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[alarum_78]

Getting my passenger side cat replaced at the dealer under warranty, didnt know the job involved dropping the transmission. I am worried the other *driver* cat will go soon. Warranty is done in 4 months on my 2010 S4.. Totally stock @ 83500km.

[Rodizzle]

Getting my passenger side cat replaced at the dealer under warranty, didnt know the job involved dropping the transmission. I am worried the other *driver* cat will go soon. Warranty is done in 4 months on my 2010 S4.. Totally stock @ 83500km.

Same boat as you , I got my driver side replaced at 48k ( stock ) . Now at 58k on a Dp set up , just waiting for the left to give out .
What were your symptoms prior the replacement of the cat ?


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[Thurston]

Will having an exhaust shop gut my stock cats, act as a test/race pipe in terms of power gains? I live in Florida, they don’t check cars for emissions here. Thinking of hitting stock cats and running straight pipes to my 034 x pipe and straight pipes all the way to some Milltek exhaust 2to1 100 mm tips. And yes, I know this will be very loud!


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I couldn't imagine it being much different whatsoever.

[bayonet14]

Have some b8.5 cats laying around that have 20k stage 1 on them ;) i will sell em

[PopTart]

Have some b8.5 cats laying around that have 20k stage 1 on them ;) i will sell em

How much?

[alarum_78]

Same boat as you , I got my driver side replaced at 48k ( stock ) . Now at 58k on a Dp set up , just waiting for the left to give out .
What were your symptoms prior the replacement of the cat ?


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Engine light, pulled a P0420 code, started noticing a rattle in the exhaust and powdery white debris sitting in the exhaust tip.

[bayonet14]

How much?

PM me

[AndrewF1]

Federal Emissions Warranty covers the Cats for 8 Years/80K Miles. Hopefully everyone that blew them took advantage of this. I just did for the 2nd time.... ugh.

https://www.epa.gov/air-pollution-tr...nd-air-quality

[MikeIC23]

Federal Emissions Warranty covers the Cats for 8 Years/80K Miles. Hopefully everyone that blew them took advantage of this. I just did for the 2nd time.... ugh.

https://www.epa.gov/air-pollution-tr...nd-air-quality

As long as the car is stock, this is a great PSA for everyone with this issue.