996 catalytic converter replacement

I have a 2004 C4S with just over 106k miles. I had a bank 1 post cat O2 failure about 6 months ago so I replaced that O2 sensor and all was fine. Recently I got a P0420 DTC (bank 1 cat efficiency) so I put in some cat cleaner in a 1/4 full tank. Worked for about 6 weeks and 500-600 miles, then the DTC returned. The exhaust system has been customized by the PO but is basically a stock system with a bit more sound. I also have the IPD intake, but I doubt either of these factor into my cat issue. I've searched the forums and agree that OEM is the ideal way to go but the price is prohibitive. I found a replacement cat from PaceSetter but the price is so low ($250) I question whether or not it is any good. One post on the forums asked about them a couple years ago but there was no reply or any other info on them I could find. So, do I replace the bank 1 cat with OEM, roll the dice with a PaceSetter or should I be thinking of just replacing both cats, either with OEM or PaceSetters? Basically I'm asking if I can mix an OEM cat with an aftermarket. I will not be required to have an annual emissions test once the car is 20 years old, which is about 2 years away so, in my thinking, I can dump the cats in two years so the replacement only has to last that long. Open to opinions and any info on the PaceSetter option. Thx

I just needed to replace my cats on my 03 4s and went with Soul Performance Sports Cats, not cheap but they produce a nice sound at low rpm and make the factory sports exhaust sound even nicer at higher rpms.

I'm fine with my exhaust sound, more throaty than stock but not loud until you get up in the RPM range. As I stated, it is a custom exhaust. My focus is getting the DTC resolved so I can get a license plate tag in NC. Does the Soul Performance Sport Cats pass emission checks? I don't know if NJ has this check but NC does, at least for me, for the next 2 years.

Quotes source post: 17752773

Not positive whether NJ does emissions anymore but I would call Soul Performance and talk to them. They are located near me in PA and they are active on RL. I'm sure they can address any questions. Good luck

Fabspeed will definitely have your answer

Take a look at the MagnaFlow OEM grade direct fit. Around $850 per side. Carb compliant if you need to worry about that kinda thing. I have both bank 1 and 2 low efficiency CEL so have been researching reasonable replacements for my 2003 Carrera.

Jon, FWIW, I am certainly not a sensor expert, but the following codes had been popping up on my durametric recently: 0420, 1109, 0172. They were suggesting that I either needed to replace my (1) 14 year old 200 cell FVD cats, or (2) my oxy sensors or (3) my MAF. ​​​​​Everything pointed to the MAF, so I replaced it, switched from my KN Engine air filter to an OEM filter to eliminate the oil residue issue, and added a can of Seafoam to my fuel to clean up the system. As a side note, my MAF was about 10 years old, Oxy sensors about 4 years old. Only been thru one tank of gas and a lot of on-off ramps at high rpm and codes aren't re-appearing. Looks like for now my oxy sensors and Cats are still in good shape. Ended up being a solution that cost me less than 225 dollars all in. You can always find MAFs on sale. Think I got mine thru FCP Euro. I am not suggesting that you have a MAF issue, but it may be worth a look with at least a cleaning before you spend 2k on cats. As it pertains to your cat question, IMHO, if you need to replace them, go with a proven company. The last thing you want is to have to replace them again in a few years. My FVD cats have seen a lot of track action and are still going strong after 14 years. There are a lot of solid choices being offered in the aftermarket from Fabspeed, Soul, FVD and many others that will undoubtedly be mentioned. They are lighter, cheaper and in many cases more durable than Oem. Plus you may get better sound and possibly a couple of HP. Unfortunately, I have never heard of Pacesetter. If you are worried about passing the emissions test, get a cat system that you know will pass. Many of the exhaust manufacturers have the oxy sensor extensions that you can buy which will help. Hope you find a solid solution.

I wouldn’t use a “cat cleaner”.. that crap ruins your oil.

U could always put in some o2 foolers, spacers, for the next year until u get outside the emmisions window.

Quotes source post: 17753520

Kenqv, why would you put it in your oil? It's a Maf cleaner.

Quotes source post: 17753544

Yeah, FVD and Fabspeed sell O2 sensor extenders. Don't know who else makes them, but they are designed to help address emission issues. As an FYI, here is a picture of the sensor extenders from FVD.

Thx for all of the input. Here are the options and prices I've found so far: FabSpeed: $2595.95 FVD: $2749.00 OEM (Sunset Porsche): $1702.69/each Magnaflow: $885/each Soul Performance: $2195 PaceSetter: $250.38/each This does not include shipping, although it does appear some of these come with free shipping.

There are a few more cat manufacturers out there with options that some of the guys will eventually tell you about. 200 cell cats will be cheaper than "Oem" like cats, but they will be louder with the need to run 02 sensor extensions so your Oxy sensors don't keep throwing codes. There is always a trade-off with exhaust systems. I would bet that a $250 cat has quite a few trade-offs. If you just bought the car and plan on taking care of it, then spend up and get the best. You will be glad you did in the long run.

GC996. I've owned the car for about 5 years and 50k miles and I have no plan to get rid of it, unless somebody makes me a real deal on a trade for a Turbo S or GT3 ;-) I agree, the $250 price point makes me think too good to be true so I will be looking at either the MagnaFlow or the Soul Performance, at least that is my current thinking. I've got 60 days before I have to pass smog, so the clock is ticking. Thanks

Been there! Good luck!

I just installed the TopGear 200 cell cross-overs a few weeks ago to replace my catless x-pipe for state inspection...was about $900 shipped (shipped here to TX from the UK in 4 days). I also replaced all four o2 sensors since two of them were throwing "no activity" codes. I have Fabspeed mufflers, so I can't say how loud the cats would actually make a stock system (really not that loud as it is, but definitely more throaty), but they throw no codes, the welds are beautiful and the fit is perfect.

Quotes source post: 17754711

Jon, have you considered upgrading to an aftermarket x pipe with 200 cell cats? Not looking to start a debate over crossovers vs x pipes, but certainly give some of them a look too, price ranges aren�t far off. FVD makes excellent products, as does fabspeed, soul and the top gear-all of these brands tend to hold up well. My combo of fvd headers and 200 cell top gear x pipe system has been very stout. Definitely worth looking at the aftermarket solutions whether it be an x pipe, or crossover system. You won�t regret it!

Late night.. meant �cat� cleaner

Quotes source post: 17755726

If you ever get the chance to run a video, love to hear it!

Quotes source post: 17758116

C2, love to hear it if you have the time to catch it on video.

Quotes source post: 17758414

agree on this

Quotes source post: 17758413

Wil do! My brother's a professional photographer, so we should be able to cook something up in the near future

Quotes source post: 17758446

Now that sounds good.

Quotes source post: 17758414

Ill have to grab a video sometime. It’s definitely loud enough that I’m happy it’s my weekend driver. Basically the combo consists of fvd headers to the 200 cell x pipe, then the (2) small total flow resonators welded into some muffler bypass pipes (pretty simple to incorporate those small units) I think Zbomb runs them with crossovers, from what I can tell from other posts. I did find a clips of a 996 GT3 running an M&M catted x pipe without any sort of muffler or resonator. Shockingly, my car has a similar tone, without the obvious higher powerband/rev range. I think running the factory size 54mm diameter with x pipe accentuates the higher pitched sound I achieve as well. GC, I’d also like to hear your setup sometime. You Tube

Bet your set-up sounds great. I am getting my act together with technology and will record the sound soon.

My 2 cents. About 4 years ago, I had to replace bank 1 CAT on my 2002 C2, because it rattled during operation (Porsche quality sometimes is not evident). Chose Magnaflow and bought only the one CAT. Unfortunately, the pipe on the new CAT was about 4 inches shorter than original. Magnaflow was no help, but the price was right for me, at the time. Had to make up a small extension piece to fit it on but the good news is that it worked well and even passed California Smog. As a bonus, it made the exhaust note noticably deeper. I kind of liked it

It works it way into the oil when they meet in the cylinder� as do all contaminates

Quotes source post: 17762618

Thanks GC, yea I�m right there with you on the tech side of things. My best ability would be to have someone film it via iPhone. Probably should invest in a go pro..

After a lot of thought I decided to roll the dice and go with the PaceSetter cats. My reasoning is pretty simple as I only need to pass smog testing here in NC for another 2 years and these cats are WAY cheaper than anything else out there, like by a factor of 3-5. I bought new gaskets and clamps only to find out the cats included the gaskets. CardiD, the seller gave me a $20 gift certificate after I asked them about the inclusions of clamps and gaskets. I used this to purchase those items from them. I then bought all new bolts, just because exhaust systems are prone to breaking bolts and I just didn't want to deal with it. Basically, I'm all in for under $600, a far cry from the closest competitor at around $1700. They quoted me 2-3 weeks but the cats got here in a week. They are, as close as I can tell, a perfect match for what is on the car. The welding is not anything near "weld ****" or "stack of dimes" and I honestly think I could have done as good a job but the bottom line is, they do seem solid and penetration, as far as I can tell, is good. Next step is to get them installed. I'll report back then. I'm only posting this as these cats came up on comments but nobody had any real feedback on them. Guess I'm the guinea pig. Stay tuned...

Quotes source post: 17777607

It will be good to hear how they perform. Who knows, maybe they will be the best thing since sliced bread.

Not sure about the sliced bread thing but I can say they are a perfect fit. Bolted right up without any hassles at all. I did have to buy new double-bolt clamps and all new bolts and nuts as they only came with gaskets. Since they gave me a $20 "gift certificate" I used that to offset most of the ancillary hardware expense. I note no difference in exhaust sound but I have a custom muffler so it is a bit more sound than stock so that is not quantitative. I also don't feel any performance difference, positive or negative. Time will tell if they last but they do come with a 2 year warranty.

Where is the post-cat bung located? On the body of the cat itself? Never mind. I went to their site and to see the post cat bung location. Thanks for the info!

Just a quick update. After about a month my ECU is clear and I have no complaints on the PaceSetter cats. As a bonus I sold my old cats for $150 to a recycler. Hope this helps somebody else in my position.

How’s the sound compared to your old system

Glad it worked out well!