vishanthram

I just have a question if anyone has removed the rear CAT's? and have they got any kind of check engine light or any error codes?? I know that the rear CAT's aren't connected to a O2 sensor, but i just want to make sure before going to the muffler shop removing those and then later on getting a check engine light and also most importantly, has it passed an emission test? Please help me. Also i have removed the resonator and put in a magnaflow muffler in the place of the stock muffler. Here is a video of the exhaust note of my car.

Solo wing

I think you'll find a lot of threads about rear cat delete.
Never mind, the sensor only monitors the front ones. you will NOT get any CEL.
For the emission test, it depends if they use the sniffing test, visual or OBD.
Some people reported passing the sniffing test after 2nd cat delete.
Regarding the visual, it depends on the place you go to and the experience of the bloke ( if he knows Mercedes has 4 cats, you might fail). As for the OBD, you'll pass as long as your 1st set is working and the OBD has all the readings.

Faiz

vishanthram

Okay, im gonna drop the rear CATS and put straight pipes in their place, lets hope that i dont fail emissions and also i hope that you are right about the CEL codes.

Do you know if these air filters are any good?

http://www.summitracing.com/parts/knn-33-2747/overview/

I have been reading and one of our trusted member, ohlord, said especially not to use K/N air filters and i want to know why. Thanks for the info. Happy

Solo wing

Why not install an x-pipe in place of the cats? I know you already have one inside the muffler. but placing the x-pipe as close to the engine will net you most gains and eliminate drone.

Regarding the air filters, K&N requires to be oiled every now and then. And sometimes the oil contaminates the MAF sensor which throws codes and cause performance issues.
Currently I'm using AFE Pro dry S filters.
http://www.summitracing.com/int/part...0084/overview/
You can read my review at:
http://www.summitracing.com/int/part...10084/reviews/

Best of luck.

vishanthram

Alright, thanks for the info and if you tell me that will get me the most net gains, then thats what i will do. Couple of our members told me to put a H pipe there instead of the X pipe. What do you think? and removing the CATS, will it make the exhaust sound louder, with or without the X or H pipe?

I read your review and i totally agree with the sound. For the first time my car crackled when up shift. Never has it done that before. I did not know that K/N filters had to be oiled!! Oiling air filters?? WHAT THE HECK, i've never heard of such thing and i am going to buy the AFE air filters then. Im going to return the K/N air filter that i bought, good thing its still sitting in the package.

Solo wing

X-pipe will give you more gains at mid-high range. the air flow at high speeds will be smoother than an H.
Straight pipes are the loudest, but the drone might be unbearable. I think an H is a little bit louder than an X.
H= muscle car sound
X= exotic sound

vishanthram

Sorry for the no response. I had my school finals. I want the exotic sound not like a mustang sound on a Mercedes. So as per your posting, im gonna go with a the x pipe. Thank you so much for the info.

vishanthram

And also i returned the K&N filter and bought the aFe Pro dry filter. I haven't noticed any exhaust sound changes as you mentioned in your review. I noticed the K&N filter was oily when taken out of the box and i asked around couple of other people and they said exactly what you said. That the oil will sometime contaminates the MAF sensor and throws off codes and sometimes CEL.

Solo wing

Give the car some time to adapt, and then you will notice performance/sound improvement.

vishanthram

how long do you think i should allow it to adapt? I will post a video of the before and after the rear CAT's are removed.

Gutentight11

What diameter is the e430 exhaust system? i was thinking of doing an xpipe right before the second set of cats, i have heard its 2"?