PeachParts Mercedes-Benz Forum - View Single Post

lrg · #11 12-28-2003, 12:09 PM

With all due respect to Hatch & Sons I think their concerns are overdone. For starters the upgrade to the '85 design is NOT a catalytic converter but rather a trap catalyst. A catalytic converter as found on a gasser is usually made from a very fine (and somewhat fragile) ceramic material coated with a platinum based catalyst that helps complete combustion. Over time (assuming it hasn't clogged first) the ceramic will collapse and the unit will fail. Since the platinum catalyst only lasts for 60-80,000 miles, the rest of the converter is designed to last about that amount of time too. On the '85 diesels the original trap oxidyzer was replaced with a trap catalyst. The original design had an interior packing not unlike steel wool that trapped the soot and allowed it more time to burn before going down the exhaust. While this worked OK, the oxidizers would get clogged easily and as such needed to be replaced every 30,000 miles. The newer trap catalyst has a more open design which does not clog but still gets the job done sufficently to satisfy the smog police. The new trap was designed to last virtually forever since there is no true catalyst to fail like on the gasser converter. You can not compare the diesel design to a gasser. While I don't argue it is simpler to just not have a trap in the first place, my suspicion is that Hatch has had very little experiences with them and is basing it's opinion upon the gas car cats. Just leave it on there or else take it off now, either way you can pretty much forget about it.