Rambino951

Hey guys, I have a CLS 63 AMG, but I figure id find the best responses on here since its somewhat related. My exhaust system looks very similar to the C63..shown here

http://www.mbpartsworld.com/showAsse...category=24395


I want to make it louder, so I just installed an X-Pipe where the Resonator is. Its still not loud enough but I did pick up some speed. Im now considering removing the 2ndary Cats..

My Question is as follows:

A: Should I straight pipe it to the Universal X-pipe I installed in the resonator area?

B: Install an H-Pipe where the 2ndary Cats are?

C: Install another X-pipe where the 2ndary Cats are?


I want to keep the backpressure characteristics of the stock system. It appears my factory setup has an H like setup at the 2ndary cats and the resonator has a small hole between the pipes as well. Now that I have a X-Pipe in place, I was thinking to put an H-pipe where the 2nday cats are to make it like the factory setup. However since I have an X-pipe now in place, is this even necessary?.. Basically.. what should I do when removing the 2ndary cats that will give me a proper flow and pressure balance like the factory exhaust, now that I have an X-pipe in.... I will be having the car tuned after this.. (Sorry if it sounds confusing)

Diabolis

A properly designed X-pipe exhaust (an entire system, not just an added X-pipe) vs. an otherwise identical system but without the X-pipe will actually make the system quieter, not louder as the X-pipe synchronizes the exhaust gas pulses from both sides of the motor which effectively cancels out the sound. An X-pipe reduces the system back pressure and provides additional scavenging, but all other things being equal, your car will sound quieter.

What you have done is made it louder by removing the resonators, but also quieter by adding the x-pipe (instead of just two straight pipes). Getting rid of the cats will also make it louder, but I don't know whether you need to pass an emissions test in your country or state, or for that matter how the ECU is going to react if you remove the pre-cats without a tune (the secondary O2 sensor after the pre-cat is now not going to see a difference that it previously did and you'll likely get a CEL).

If you just want more sound, either remove the X-pipe and replace the resonators with straight pipes, or alternatively get a complete cat-back exhaust system w/o resonators.

If you want "(proper) flow and pressure balance like the factory exhaust", don't f*** with it. An X-pipe is by definition going to affect the exhaust gas flow and back pressure.

Diabolis

Oh - and for an X-pipe (or an H-pipe) to have the maximum effect, it would need to be in front of the cats, not after. Just like the factory H-pipe in the picture.