ronn1

iTrader: (1)

Been doing some research on metallic vs ceramic. Two big advantages of Metallic over ceramic are flow and strength. One caveat though...
Most HFCs (if not almost all) with metallic cats have a SINGLE rolled core vs a dual (or tripple) rolled core. The single cores are prone to *telescoping* under stress which can blow the centers out! That makes them actually MORE prone to this than Ceramic (*honeycomb brick*) in this particular type of failure. Multiple metallic cores are MUCH stonger and cost a LOT more as well. This was also the opinion of Kinetix (they make ceramic cores..special 200 cell) when I discussed the subject with them to confirm this.

Here is the multiple core found on many high end Euro cars:

http://www.custom-performance.net/pr....asp?idpage=11

The unique S - Matrix design of the metallic core of the HJS catalysts is a superior construction which will not telescope under heavy load. The internal winding feather two flat and two corrugated foils culminating at two winding centers as centroid. This unique design increase exhaust flow over what is typically seen with standard 200 cell metallic substrate converters.


HJS Catalytic Converters:
100% Stainless Steel High Quality Metallic Matrix which will withstand extreme temperatures that can damage other metallic and ceramic catalysts.
Unique S-winding construction, which makes it four times more durable than other metallic catalysts. This construction also prevents breakdown and telescoping, which other catalytic converters are prone to.

HERE IS SINGLE by MAGNAFLOW..type used on Berks..etc:


From another article:

Another large price factor is the actual construction method of the core. Low cost, commonly used domestic metal cats that run around $80-100 each not only have a bare minimum of precious metal coating, but they are also a wound construction.

Corrugated metal sheets are "wound" into a cylinder, and stuffed in a can. Such a simple construction methods typically result in "telescoping" of the core center over time, which ultimately destroys the cat:

rcdash

iTrader: (18)

Thanks for sharing your research. If the difference is $100 vs $500, I'll take the simple $100 cat and take my chances for a rare failure... I'm surprised there is a market for the "S" type at that price point.

ronn1

iTrader: (1)

It's just that everyone is saying Metallic is stonger than ceramic...not true for most aftermarket HFCs. They do flow better..but one Co (kinetix) has built a special 200 Cell that is *close* in flow..not equal..with prolly equal, if not better, resistance to blowing out.
I wonder if more cells..like FI HFC,with 300 cells, is more resistant to telescoping than standard 200 C? That would seem to make sense.