ajahearn

My driver side has failed and caused me a lot of grief (heat melted parts of the harness and destroyed all the O2 sensors). However, I want to get the car back on the road and the track. Porsche says these need to be replaced at 10 years and that is where mine are. Does it make sense to replace both? Thanks.

MrMoose

Pretty certain they do not say that. There's no way a cat converter needs to be changed on a fixed schedule, you replace them when and if they fail.

Also they typically don't fail on their own: if yours melted I suspect you either had a rich running condition, or physical damage to the cat that cracked the matrix. Both of those will cause overheating and damage.

TMc993

If it was my car, I'd do both but not without a thorough assessment of what else might need to be done. If the list of "while you're in there" stuff was extensive, I'd seriously consider doing the minimum repair and getting rid of the car. Sometimes, you just need to cut your losses and move on.

ajahearn

I did a search of Does your Porsche need a new catalytic

10 years
The “Rule of 10” For most vehicles, Porsches included, the suggested part life of a cat is only 10 years when driven regularly (especially in areas where road salt is used in wintertime). In addition to this, 100,000 miles is the traditional “life of a car,” and therefore also the cat.Jul 15, 2022

Here are a two of those links.
https://www.porschebeachwood.com/blo...tic-converter/
https://www.porscheelpaso.com/blog/s...er-is-clogged/

The problem I had was a hole formed in the casing but behind the shield. That hole allowed enough heat out to melt anything plastic nearby. I was on my 1st lap of my last session at Sonoma when I heard the exhaust note change. I exited immediately but the damage was done.

ajahearn

You make a good point about cutting losses. I'm looking at about $8-10k worth of work and parts. While they are in there I am going to have the AOS replaced as well.

I see plenty of older cars on the track but I am concerned that this is only the beginning. I had a small oil leak earlier this year and that was another $3k otherwise it has only been maintenance items up to now. I still worry about the longevity of the PDK.

MrMoose

It says "suggested part life". That's not the same as saying "replace the cat at 10 years": there is no reason to replace a functioning cat converter solely based on age or mileage. From the wording there that's based on the cat rusting through in the salt belt rather than it wearing out. It's a guideline for what to expect, but actual life is going to depend on where/how you drive the car.

(Hell, if you follow those guidelines you should be throwing your car away at 10 years or 100K, lol)

Now, that said, if your left cat rusted through then it's likely that the other side is in similarly poor condition at this point, and it may need replacing. But base that on an inspection, not just on age.

Larson E. Rapp

In other news, the barber says you need a haircut.

ajahearn

I apologize for overstating Porsche's position. Also as a Northern CA - bay area resident, not close to the ocean, I am not worried about salt. But based on my experience (limited), Porsche does a recommended list - not a required list. Example, changing oil at 1 year - does a DD need an oil change every year? But I change mine 2x a year because I punish the car at the track.

But there are times Porsche is not so up front about things. Another painful example, caliper bolts - I was always very careful to torque my bolts and yet I had to replace the knuckle because steel into aluminum doesn't take a lot. Then I find out that they have a GT3 kit of caliper studs for <$100. So to save at most a few dollars, Porsche (aka Volkswagen) opted for bolts instead of studs. So when Porsche does "suggest" replacing catalytics at 10 years I start to wonder if there is a hidden message here. Do not take this as an admonishment of your message. I understand your viewpoint and I have received similar advice from others. But then I also get the counter advice - do you have a fire suppression system? No, then I would replace both.

There are a lot of older cars at the events I go to, possibly some before I was born (but unlikely). I would love to have my car for the next 10 years so I want to do what is best for the car knowing that I am going to punish it 10-15 days a year.

Thanks to TMc993 because I think more like them. It is a question of which causes you more sleepless nights? The thought that a 2nd catalytic will fail or spending another $3k unnecessarily. I haven't figured that out yet which leads me to believe it is the former that will keep me up at night.

Ernest72

Personally I would upgrade to aftermarket catted headers if I had to replace the stock ones. For the money you get great sound and performance.

ajahearn

I toyed with that idea but I am trying to keep this cost down and I can "trade in" my old cats to Porsche for a core charge. Not sure if I could do that with aftermarket. Besides I am already a fan of the sound. But thanks for the suggestion.