Quote:
Originally Posted by StellaTheZJ
Remember though that "knocking out the honeycomb" of a failed cat may not have the same results as replacing a functioning cat. What caused the cat you knocked out to fail? If excessive missfires has resulted in a cat overtemp and partially melted the matrix, the cat would have become restrictive.
On the other hand, replacing a functioning cat with a pipe seems to have been tested to be non-productive (according to earlier posts). I haven't tested this, so I'm not arguing one way or the other, just pointing out that for this thread to be meaningful, we need to compare apples to apples, eg replacing good cats with pipes.  |
Very good points.
One of the cats I knocked out had failed mechanically on my GFs S-10. The honeycomb disconnected from the rest of the cat housing and would rattle loudly.
2 others had failed likely due to their age and heavy use (15years - 200,000+ miles on the cars). Visually there were no abnormal restrictions in the honeycomb when I knocked it out, but that doesn't mean they flowed as efficiently as intended.