Replacing Catalytic Converters in a '98

[magno_grail]

A '98 with about 80k miles, the converters are starting to give out the sulfur dioxide smell indicating they are failing. Last smog test passed but high. Owner wants to replace them before they fail. These are the options, ~$2000 each for OEM (illegal to buy used in CA) but CARB lists approved replacements. E-mailed CARB about the replacements, told they do not allow replacing them until they fail SMOG (CARB would prefer you drive a high pollution vehicle than replace the converters early), would have to get referee approval first. Waited a couple months, missed their one unidentified caller reply, E-mailed again, told needed approval from a referee, never got back. That was over six months ago. I am taking no reply as approval.
So, they have about eleven replacements approved. Turns out two (L/R complete from manifold to muffler) have not been made yet (likely never will be) and all but two of the rest will not physically fit. Around five on the list are from the same manufacturer but listed under different company names. Seems obvious someone is getting paid to approve these replacements regardless whether they can fit.
Two will fit, however, CARB's rules say you cannot modify the converter or change the size of the inlet/outlet. Well that is stupid as the openings on the replacements is far larger than the Boxster pipes.
Also the rules state the O2 sensors have to be in the original position which is on the rear cone of the converter which obviously cannot be done without modifying the converter.
Plus the heat shield and support bracket are part of the body.
The point of all this is I am going to make a jig to weld the replacements in, keeping the original front and rear cones and mountings.
Is this something anyone would be interested in hearing about? Already I found the description of how to remove the converters in the Bentley manual is very incomplete.

[gonz]

At some time, all of our catalytic converters are going to fail and all the used ones will be gone to the people that can use them. Having your replacement info would be great.

[JFP in PA]

Guys, I have been listening to conversations like this for some time now, so let me give you a shop owner's view on the subject:

Yes, OEM cats are pricey, thats why people steal them. More and more states are restricting the use of used cats due to this problem. The low cost aftermarket is questionable; lower cost cat replacements often do not pass emissions sniffer tests, fitment is questionable and draws attention to inspectors that they are not factory. So when we get a customer that has either failed emissions testing, or the car is throwing codes saying that the cats are "aging out" (read dying); we tell them we will only use new OEM cats. If they don't like that answer, I tell them to take it any other shop they want to use, but we will not install parts that we know are going to be problematic and result in comebacks or worse.

So, to sum up: Yes, new OEM cats are pricey; if they are outside your budget, I'd suggest selling the car and buying something you can afford rather than spending time and money to try to evade the inevitable..........

[gonz]

I totally understand your view, JFP. I'd still like to see what he does.

[magno_grail]

Of course OEM would be preferred, however, the price of two converters plus installation exceeds the value of most Boxsters this age. Plus, you would have a hard time selling a car that does not pass emissions.
CARB jokingly says that the converters are designed to last the life of the vehicle. In this case that would be true, the car would be junked unless you really want to keep the car.
The Valina converters meet the CARB requirements and are approved, although not if installed.
Inspectors here never physically check the converter or put the probe up the tail pipe, only go by the OBD2 test. OBD1 cars are sniffer tested because they do not have the second set of O2 sensors.
Pelican sells many parts that are not OEM but are equivalent. Does everyone only buy the Porsche parts?
Checked again, there are 35 converters on the CARB list but only two possibly fit.
Should note that shops are not likely to do this as it needs a jig to hold the parts in place for welding and they would have to be able to weld stainless steel. It would be like asking them to swap out the EEPROM chip in the immobilizer from your old one so it would not have to be programmed for your old keys.

[JFP in PA]

Originally Posted by magno_grail

Pelican sells many parts that are not OEM but are equivalent.

Pelican sells parts they claim are equivalent, but have proven not to be, which is why many do not buy anything from them................