akreidie1

How do i pass my emmisions if i take out my Cats, how does the O2 sensors work? I have a C63 and got the Kleemann K1 ECU upgrade with it programmed with (CAT OMIT). any help will be much appreciated

rantarC63

There are two sets of O2 sensors in each bank; one is before the cat and the other is after the cat. The difference in the readings between the two sensors tell the ECU whether the cats are doing their job. You can remove the cat but you must disable the post-cat sensor if you are to avoid a CEL. If your emissions testing takes measurements from the exhaust (i.e., muffler), you will not pass inspection. You would need to reinstall the cat. Don't know if any state takes emissions readings from the car's computer.

akreidie1

Does gutting your cats out void your warranty? and is it possible to put your cats back on, and would anyone know Joe much it would cost?

rantarC63

There is a common misconception that modifying something on your car will void the entire warranty. The modification has to be the cause of the failure in order for MB to be able to decline coverage on that particular failure. For example, if you change the stock mufflers and then have an engine problem MB will not be able to deny warranty repair on your engine. They may try to BS you but they legally cannot. Now, gutting your cats will void the warranty on the cats. After all, you are destroying them. Whether it voids the warranty on other parts of your emissions systems is arguable. Depends on the particular failure.

You could take your cats on and off but that is a lot of labor and it will be costly. Also, the cats are generally welded to the midpipes (bolted to the headers) so it will require cutting and welding each time unless you come up with a clamping system. Using clamps will be prone to exhaust leaks.

Now I have to ask..what it is that you are hoping to accomplish by removing the cats? You are not going to get a large amount of power by removing them but the car will get very loud (too loud IMO). You're better off installing a set of headers and high flow cats (that will still provide sufficient emissions control to pass testing but that will flow better than stock). Do you really want someone messing around with your exhaust over and over again? I think you are only asking for problems.

dmyrick

rantar, good info, i thought that any little thing could void your warranty.

akreidie1

I heard I could get around 20+hp by gutting the cats out, anyone think or heard different?