fefo25

Has anyone deleted the secondary cats on the C300? I'm thinking about doing it but would love to hear it first.

wnunez89

i thought about doing this as well but after doing some searching on here ive found that:
1) the car seemed more "slugish"
2) the car was actually quieter

sagar350z

If i remember correctly this would void your warranty. Can someone please confirm?

wnunez89

only if the dealer can prove that this mod caused the issue

sagar350z

Ah i see.. Well thanks for the correction.

fefo25

Does anyone have a video?

kirillbenz22

one of the guys or two actually did it on this forum but i never heard the results, but i spoke the mechanics at MB before because I was worried about my no mufflers and x pipe and they told me no problem as long as I do not touch the cats. They will find a way to blame you if you touch the cats. I was thinking of doing it still considering but I heard that it is very illegal.

Mixedfruits

no mufflers are illegal too though .... LOL

kirillbenz22

true but i am not sure how much the penalty will be in terms of money for noise vs pollution...

Acapulco Bill

There should be pre-cat and post-cat oxygen sensors on the W204. If the cat is removed, the sensors will (correctly) send identical information (readings) to the ECU, which is expecting a change in O2 levels (should be substantially lower in the post-cat sensor of course). The ECU will try to compensate by changing the quantity of fuel supplied to the engine, causing it to run improperly.
On my V12, a faulty O2 sensor cause the ECU to make the fuel mixture too rich, which eventually destroyed the cat convertor. Had to replace both the cats and the sensors, an expensive proposition. Recommend not removing the cats, or perhaps replacing them with high performance units such as the Magnaflows.

blokrocbet

20 years in dealer operation, and in my opnion most dealers would void the warentee. However there is a imposter cat available. **** the same but no flow restricting mesh

Also for the above broblem you could wire in a resister to fool the ECU 2 ohm should do the trick. just double check my math im getting a little tierd

glovemoney

So I order and receive my high flow cats today with the intent on using them as a replacement for my secondary cats for the C350. After some hunting and pecking, I find a place willing to them swap them out. I leave my car w/ the shop and 15 minutes later the mech calls me and says that the "secondary cats" are not cats. But are resonators...ie. no filament in them. FWIW, I currently have a resonator delete and x-pipe. He goes on to say I wouldn't want to add a cat to it but straight pipes... I make a quick but confused decision and say ok...

Whatcha think?

RLE

Not to mention your spelling.

fefo25

how does it sound...any sound clips

burnteggroll

here is a sound clip of my temp setup i had about 2 years ago, which i still have. 2nd cat delete w/ x-pipe. the c300 with this setup will sound just a tad different than a c350. i noticed that when i had my car next to a c300 with similar setup.

http://www.youtube.com/watch?v=nHOnnDEiOrw



the slugglish that some peps are talking about all depends on their setup. for mine, the sluggish was anticipated which happen noticeably in the first 1-3 days (depend on how often you drive your car). i was floorin' this baby but she didn't want to go.


http://www.youtube.com/watch?v=1otk-UrhCw4



on the 3-5 days, the sluggish will disappear as the ecu will adapt to your driving behavior and adjust to the new air flow. if u notice the car is getting a little quicker as day pass. it took my car 1 1/2 weeks until it was settle.

http://www.youtube.com/watch?v=r4T08GujPCY

envyxc350

I was running headers, primary cat delete, secondary cats, x-pipe, stock mufflers, quad tips. Loved the sound. Had a CEL but i could care less, I drive it like I stole it every time.

burnteggroll

i could care less, I drive it like I stole it every time.[/quote]

+1

fefo25

+1 [/QUOTE]

Did it settle back to its normal power or quicker?

glovemoney

Called an audible and remove the straight pipe to be replaced with Thunderbolt high flow cats. End result here (i didn't want to wake the family or neighbors, hence the low rev).

http://www.youtube.com/watch?v=68h7u7tKgtQ&feature=player_detailpage

fefo25

Can you post a better video, higher rev??

glovemoney

More revsticles?

http://www.youtube.com/watch?v=0UcIx...yer_detailpage

JG*

hey, when deleting the second cat did you have to reinstall any o2 sensors? Or is it as simple as cutting them out and welding in straight pipes?