Mongo

The fact that CA passed a law requiring manufacturers to stamp CA certified on the heatshield or else it is illegal never sat well with me. If you look at the law in writing, it was to prevent the distribution of poorly made cats for street use, implementing a 5 year warranty for any CA certified cat on a vehicle.

Since the cat has failed prematurely, you can go after Magnaflow for a free replacement or take it up with the state (which I believe the latter will get you nowhere unless you tell them it is racist).

mj1pate

Really, typically “Bill Ball informative”. Thanks for giving the history of this effort. It’s actually helpful in all 50 states.
Although I live in Maryland, where my 86.5 is “Historically” plated and exempt from emissions, we are supposed to leave our emissions bone stock. Mine has been stock for the last 13 years until soon.
My cats were abused pretty badly when I was trouble shooting what turned out to be a MAF problem. In the initial stage I drove it 3 miles home, stumbling all the way instead of having it towed. I’ve decided to (at least temporarily) delete the cats while I decide on the most productive, least expensive long solution with new cats. The “catalyst” for the decision to delete was based partly on the above (I don’t trust them now) and the following educational incident:
A month ago my son’s Civic experienced a sudden failure while being driven. When he opened the hood, his visible cat was glowing. The cause was the cam position sensor losing its mount with both it and the bolt falling down into the depths of the TB cover. Consequential damage was significant but not fatal. Back to the cats: the car came to a stop within 20 seconds. A post mort on the cats revealed significant melt/blockage and this was (again) after just 20 seconds. Therefore my concern about 30 year old, abused cats. So, in short any information such as what Bill is submitting about affordable, hopefully durable cats is really helpful... particularly for us who want to properly remediate working cats once.

GregBBRD

The reality of catalytic converters:

All of the aftermarket catalytic converters, that I've used or seen used, will only last for a couple of years. There's simply not enough of the precious metals (simply look at the prices of these parts and do some math) to make them function for extended periods of time (yes, I know they have to be warrantied for 5 years, but try and "collect" on that warranty).

The factory cats will last virtually forever.....or until they get severely abused. They are very expensive, not only because Porsche had them made, but also because they have a lot of the precious metals in them, to make them last.

I change very few factory cats. Generally, if you can repair the "issues" with the engine, the cats will still work.

There are cases where the cats will get hot enough (severe abuse) to ruin the honeycomb structure. These cats will have to be replaced. The absolute best solution is to find a used 928 cat and install it. Yes, I know that the catalytic "lobby" has made used cats "illegal" to sell or install (to protect their market), but a good used 928 cat is 10X the cat that any aftermarket cat is. And what happens at home isn't likely to be an issue, with the government....how would they ever know?

It's pretty simple to "judge" factory cats, from afar. If they still have the "stainless" appearance on the inlet pipes, you can almost be certain they are great cats. The darker the entry pipes get (and the heat shields), the less certain you can be of their function.