I just had a new engine fitting on the weekend and just prior to having it installed I gave my car an good thrashing, as one does when he's getting a new engine
Anyway, in doing so my old cat collapsed blocked off about 75% of the airflow thru it. For the mean time the situation has been "remedied" so I can drive the car but obviously being a good law abiding citizen I'm going to replace it shortly.
Problem B: chunks of the cat internals seem to have ventured down through the rest of the exhaust into the muffler and generally throughout (I can hear it rattling)
I went to an exhaust place today and they quoted me $300 to fit a new cat and clean the rest of the system out - which involves having to remove it all and then reweld it back on in sections. $280 of that price is supposedly the price of the 2.5" cat. I've seen cats around for less than that, and even 3" ones for around $200.
Is it worthwhile going from my 2.5" extractors to a 3" cat and then back to the 2.5" cat back system or should I just stick with a 2.5" straight through? According to autospeed "a high quality aftermarket cat converter has about the same flow restriction as a low-grade muffler of the same diameter"
Then there's the AU/BA cat...
What have others used and found to be good/bad or indifferent ?