Had the "sec cats" removed on my m272 c230, obviously they were nothing but resonators. straight through with perforated walls w/ packing.

is this the case w/ each of the w203s? Specifically a '04 c320 that my buddy is purchasing tomorrow.

When I had my headers installed my exhaust guy checked out my "secondary cats" and they had no honey comb. They were infact resonators.

Some members claim they do have secondary cats and they do have a honey comb inside (mine for sure was a resonator)

Yes - I've been argued with on this forum in this regard. To my knowledge they are resonators. If they were Cats then why is the post Cat O2 sensor not after them?

because they arent cats.

they didnt even slightly resemble cats, i mean, there was NO smog cleaning of any type going on inside what my mechanic cut off. they looked like two tiny german glasspack mufflers

took mine it to get removed today and found out that they ARE cats. At least on my car. So he wouldn't remove them.

did you see the honeycomb covering the entire inside of the "cat" yourself?

no not me personally, but I did watch them cut off the piping and look inside and they turned to me and said yep its a CAT. Plus he said there was tons of markings on it that indicated it was a CAT and it was much hotter than the piping which also helps indicate it is a CAT due to the rxn going on inside.

I should just cut it off myself and take it to an exhaust shop and be like I just found this like this, lol...

You guys want to hear something weird??

When my exhaust guy was doing my headers, we noticed my passenger side exhaust pipe was thicker than my drivers side pipe

I have no idea why? Maybe right side is thicker so exhaust gas can pass quickly and merge on the left side where muffler is???

Maybe M271 & M112 do have a secondary clean up cat?? & newer engines not. I still don't see why the Cat efficiency O2 sensor is not after this though.

perhaps it is just for very minor clean up and noise reduction.

BMWs are the same way at least on the e90/92 that I've observed. speaking of the 02 sensor that is. they only have them after the primary.

yeah i got my secondary cats taken off as well and i looked inside and they were just resonators.... my exhaust guy didn't want to take them off thinking they were cats but i told them too anyways and after the cut, realized it wasn't cats and he was actually happy

ya fine. I'm muy jealous now!

m111 I think :paranoid: Or whatever engine that goes in the 02 C230K

http://www.youtube.com/watch?v=ToxVi...layer_embedded

where did you get your headers?