Secondary cat delete??
MBWorld Fanatic!
Joined: Mar 2009
Posts: 1,177
Likes: 2
From: UCF area Orlando/West Palm Beach FL.
c350coupe, Gencoupe R-spec
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
1) the car seemed more "slugish"
2) the car was actually quieter
Member
Joined: Nov 2010
Posts: 158
Likes: 0
From: NJ
2012 C350 coupe
MBWorld Fanatic!
Joined: Mar 2009
Posts: 1,177
Likes: 2
From: UCF area Orlando/West Palm Beach FL.
c350coupe, Gencoupe R-spec
Member
Joined: Mar 2010
Posts: 214
Likes: 0
From: LA
MB C-300 Sport 2009 Manual Black XPIPE+Exhaust
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.
Trending Topics
MBWorld Fanatic!
Joined: Dec 2010
Posts: 1,170
Likes: 1
From: 626
E63 Black on Black
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.
MB World Stories
The Best of Mercedes & AMG
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
Member
Joined: Mar 2010
Posts: 214
Likes: 0
From: LA
MB C-300 Sport 2009 Manual Black XPIPE+Exhaust
MBWorld Fanatic!
Joined: Oct 2010
Posts: 1,128
Likes: 19
From: Acapulco Mexico
2010 C300 Sport
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.
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.
Junior Member
Joined: Jun 2010
Posts: 40
Likes: 0
2009 C350
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
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
Member
Joined: Feb 2011
Posts: 134
Likes: 0
From: Dallas
2010 C63
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?
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?
MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,986
Likes: 6
From: SEATTLE WASHINGTON USA
'08 C300 Lux Barolo Red Beige Leather P2 MM 18" wheels '84 944
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
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
Thread Starter
Senior Member
Joined: Sep 2010
Posts: 293
Likes: 0
From: Bergen County,NJ
2010 C300 Sport 6 speed Steel Gray
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?
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?
Senior Member
Joined: Jul 2009
Posts: 262
Likes: 1
From: Farm Country/SoCal
w204 - 350 N other white cars
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
Thread Starter
Senior Member
Joined: Sep 2010
Posts: 293
Likes: 0
From: Bergen County,NJ
2010 C300 Sport 6 speed Steel Gray
Member
Joined: Feb 2011
Posts: 134
Likes: 0
From: Dallas
2010 C63
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
http://www.youtube.com/watch?v=68h7u7tKgtQ&feature=player_detailpage
Last edited by glovemoney; Apr 9, 2011 at 12:53 PM.
Member
Joined: Feb 2011
Posts: 134
Likes: 0
From: Dallas
2010 C63
Junior Member
Joined: Mar 2015
Posts: 25
Likes: 0
From: Vancouver
C350
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
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
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?
