How many miles can you expect from a catalytic converter?

[B5NUT]

I know the emissions on my 1.8T are close to the limit, so I'm looking around for another cat. Now the question is how many mile can a catalytic converter go for, I know replaced on in my 1.8ADR engine at 120K miles, and I know it's need to be replaced again 230K miles as it's making a rattling noise.

I'm going to have to replace the manifold (when the weather improves), so may as well do the cat at the same time, the question is should I bite the bullet & go for a new after market cat or get a second hand one? I've been offered one which has already done 120K miles, so wondering if this would work for another 30K+ miles or is 100K miles about the life of a catalytic converter?

 

[aragorn]

I fitted a Bosal cat to ours when we got it, because its original cat had failed the MOT. Turned out the original one had been gutted by the previous owner, and the car had 150k on it, so one could assume that it had failed at some point before 150k (and the state of the bolts suggested it had been on there a while in that state)

A year later and the new cat was struggling to pass the emissions test. Guy had to sit with the engine at 3000rpm for a good 5 minutes before the values finally dropped enough to pass, and even then it was a middle of the road figure, rather than the usual 0% figure a working audi cat will give you.

 

[AndyMac]

Both mine have just gone on my 2.8Q (last week) at 180k miles and they were original as I've had the car from 32k. Had them replaced with aftermarket ones from eurocats £350 fitted, they were about £135 each.

 

[B5NUT]

Thanks guy's. I now have more questions than answers