amg-09c63-amg

i was thinking if i was able to remove my 2ndary cats and replace it with straight pipes w/o an ecu tune is that possible or would i be feeding my engine with too much fuel and making it lean

-inexperienced & first time tuner

mthis

you can do it with out a problem no need to tune the car for that and no CEL's will pop up the 2nd cats dont triger CEL's when removed. i did this thats how i know. also what i would do if i had another c63 and dint want to spend alot of cash. delete all cats and get 02 simulators no CEL's add a lil power. throw a tune in the mix and you ahead of the game.

amg-09c63-amg

thanks for the fast response. how about removing my 2ndaries and replacing with an X crossover into a straight(removed my res.).

aroonkl

I got my 2nd Cat out and put straight pipes in place. 700 miles= no CEL.

SonnyakaPig

Can u guys help me conceptualize the positions of the cats? Does it go, exhaust manifold, cat, cat, x-pipe/"resonator" -- in that order?

And the secondary cat doesn't have an O2 sensor, so no CEL's?

If my understanding is correct, I may just do this, because I want to increase the sound level of my exhaust. I love the stock sound, but I just wish it was louder.

I think this might be a good combination with a more free flowing x-pipe as a replacement for the OEM one.

amg-09c63-amg

yeah. same thats exactly what i want to do. hopefully someone w/ experience can help us out.

Militia

A bit off topic, but have you heard the car roar from outside the cockpit? It wasn't until a few weeks after I purchased it that I actually heard the car from outside; a friend took it for a spin around the block and I was actually very much impressed by the note!

hhughes1

The secondary cats are located just in front of the resonator and do not have O2 bungs. After my K2 package was installed I was a bit disappointed that the exhaust note had not changed much from stock which was a little to quiet for my taste. That afternoon the secondary cats were replaced with straight pipes and the exhaust db level went up significantly. Considering how much power this motor gains by unrestricting the exhaust, I would think that any cat deletion would make power as a stand alone option. The clip below was PRIOR to LTH installation and the exhaust note was much more affected by the secondary cat deletion than the K2 hardware.

http://www.youtube.com/watch?v=O--a60gZZVk

PetroC63

That video was with Kleeman shorty headers, hi-flow primary cats
and secondary cat delete?

Sounds great.

SonnyakaPig

I would like to do a before and after dyno for the secondary cat delete on an otherwise stock car. Maybe I'll give this a try in the next couple of weeks.

SonnyakaPig

Sorry for taking so long to return to this thread and see your post. To answer your question, I have not heard the car really get on it while I was standing outside. But, I have heard one pass by my car on the freeway and I was very impressed by the sound and also how long I could hear it as it drove away.

I agree, it has a great note!

SonnyakaPig

Awesome video. Does your car have a LSD?

amg-09c63-amg

i just got my 2ndary cats removed for 150 and replaced it w/ a stainless steel xpipe
will post a vid when i can. i miss the stock tone but.. i keep steppin on the pedal for this more aggressive sound

AMS Performance

+1 smart move, if you remove 2nd cats ... put a stainless X-pipe in its place. This is the best route to go as it makes the most power of all the options (better than high flow cats, or just straight pipes)