18 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHCatalytic Converters
Reported or suspected cause
others
Suggestion or failed attempt
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause · Original poster
I do appreciate that selecting an exhaust is somewhat personal, but I wonder if it would be helpful to me, and I suspect others on the list, if we could somehow quantify the various options based on just the sound changes.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
I'm the original owner of an '04 C4S with 36k on the clock, have been hearing the exhaust rattle for quite some time and now the CEL has come on, codes indicate Cat in bank 1 is not operating well and after reading the posts I'm leaning to replacing the cross pipe and Cats with the Fabspeed option.
Leading evidence: 'others' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'others' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Replace cross pipe and cats' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
I'm the original owner of an '04 C4S with 36k on the clock, have been hearing the exhaust rattle for quite some time and now the CEL has come on, codes indicate Cat in bank 1 is not operating well and after reading the posts I'm leaning to replacing the cross pipe and Cats with the Fabspeed option.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
Here a clip from when I was testing my rear bumper mic setup
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
The past few years I have been using the car for DE's and wonder if the heat/cool cycles contributed to the failure of the Cat and if the Fabspeed Cat is more resistant to this because I plan to do a lot more DE's in the future.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Replace cross pipe and cats
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
I'm the original owner of an '04 C4S with 36k on the clock, have been hearing the exhaust rattle for quite some time and now the CEL has come on, codes indicate Cat in bank 1 is not operating well and after reading the posts I'm leaning to replacing the cross pipe and Cats with the Fabspeed option.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
The past few years I have been using the car for DE's and wonder if the heat/cool cycles contributed to the failure of the Cat and if the Fabspeed Cat is more resistant to this because I plan to do a lot more DE's in the future.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
others
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause · Original poster
I do appreciate that selecting an exhaust is somewhat personal, but I wonder if it would be helpful to me, and I suspect others on the list, if we could somehow quantify the various options based on just the sound changes.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
18 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T130754Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I'm the original owner of an '04 C4S with 36k on the clock, have been hearing the exhaust rattle for quite some time and now the CEL has come on, codes indicate Cat in bank 1 is not operating well and after reading the posts I'm leaning to replacing the cross pipe and Cats with the Fabspeed option. The past few years I have been using the car for DE's and wonder if the heat/cool cycles contributed to the failure of the Cat and if the Fabspeed Cat is more resistant to this because I plan to do a lot more DE's in the future. Also, are the Fabspeed mufflers a must do or strictly optional?
The usage might have contributed to the premature failure of the converter but I'd be more inclined to attribute failure to a "new" part failure. The car only has 36K miles and this is well under the 50K miles the new car warranty covers. In fact converters are covered by an emissions related warranty and are covered for 70K (or more now) miles and 7 or 8 years after manufacture.
For your questions regarding the after market converter and mufflers I can't help you.
I had the same issue and mine started rattling in the middle of a DE about a year ago. Was glad it was a cat considering the myriad of other things it could have been. I replaced mine with 200 cell x-pipe cats from SpeedTech. I already had a FabSpeed exhaust. I really like how the cats transformed the car in means of sound, a little more GT3 esq. I also have more grunt above 3k RPM. I have done several DEs with no issue over the last year.
Alas, I do need to reinstall the Cat, and will consider others as well, my failure is definitely premature and in fact I think in retrospect I've been hearing some "rattling" for several years now, but when you mentioned "usage", did you mean low mileage per year or hard usage with DE's??
If I were you, i'd take out the cats if you do any serious track work. I have gone through FOUR sets....the cats overheat due to full throttle conditions (Bosch dumps fuel) and then they promptly develop cracks in the honeycomb structure inside which results in the rattling you hear. Which in turn leads to check engine light, which in turn leads you to spending lots of money on OE cats. Depending on where you live, this means you are buying pricy OE cats as aftermarket cats are not allowed (The cargraphic ones are a good replacement alternative as they change out the honeycomb catalytic material inside with OE housing). Moreover, the 200 cell ones are not guaranteed to pass either other than the fact that they would probably fail visual if you are in a nanny state like CA.
This is well enough known issue. It is almost always the same bank too.
Good luck.
My 200 cell fabspeed x-pipe cats have lasted for 4+ years racing POC/PCA... they have held up great. Stock cats can't handle track driving for whatever reason: the upstream "puck" gets blown out of position into the O2 sensor which is when the CEL comes on.
That was very helpful information on the longevity part of the decision. I do appreciate that selecting an exhaust is somewhat personal, but I wonder if it would be helpful to me, and I suspect others on the list, if we could somehow quantify the various options based on just the sound changes. If stock is a 1 on a scale of 1-10, where would you rate the other options? And the more opinions the better.
Stock Cat and stock muffler- 1
200 cell Cat and stock muffler-
Stock Cat and aftermarket muffler-
200 cell cat and aftermarket muffler-
Aftermarket headers, 200 cell cat and aftermarket muffler-
This should be interesting....
Can't comment on longevity of 200 cells or all the various combinations of above, but I've had NHP's 200 cell cats (non x-pipe) on my car for 7k miles with the stock exhaust and I think it sounds pretty great. Originally I could barely hear the stock exhaust, and now a decent amount of sound gets in the cabin when the windows are up. No droning at all. Pretty sure they were only around $1400 too.
Here a clip from when I was testing my rear bumper mic setup
Porsche 996 Stock Exhaust and NHP 200 Cell Cats from Maxspeed Motorsports - YouTube
Nice video and great sound, slightly off topic but what shifter do you have is it a 997 SSK?
Im outing for Cargraphic 200 CEL x pipes and headers soon. When I mean soon I mean when the AUD is stronger... sigh.
Already have Cargraphic mufflers and they sound amazing!
I have the standard 997 shifter (which is slightly shorter than the 996) but not quite as short as the factory SSK. You can get these used in great shape for less than $100 on ebay, I also got some aluminum shift bushings from phenixengineering.com to make it a bootleg 997 GT3 shifter.
Give Nello @ MaxSpeed Motorsports a call; the NHP cats that are the most like our stock configuration, but 200 CEL are a great choice. You will not lose back pressure and low end torque like several other options. Here's a BIG plus, these cats are warrantied for life, including track use. Fabspeed emailed me that their warranty would not cover track use.
http://www.maxspeed-motorsports.com/...onverters.html
Nice, I've bought one and its waiting to be installed
your car sounds great. I wish I could find a road here to rev out gears 1-4 all the way. I'd be in jail if I did that here!
Aren't some roads in the north unrestricted? The Stuart highway? Could be a bit of a drive but at least when you open the engine up you won't go to jail.
I think there are some unrestricted sections in NT but its thousands of kms from me in the middle of a desert...
When thats the first result I might stay away from there but thanks for the suggestion!!
You say "thousands of kms from me" like it is a bad thing.
You get to drive you 996 thousands of kms and then do the nasty WOT thing without fear of arrest then drive your 996 thousands of kms home again.
What's wrong with that?
