I'm going to install an exhaust cut out pipe but need to know which size pipe to purchase. Does anyone know if its 2.5" or 3"? I want it installed right before the muffler/after the secondary cats.

 

2.5 is the closest size to OEM piping. OEM is technically 2.35" OD but its close enough to weld-up. You can get a 2.25" and have the exhaust shop expand it out too as well (if they are competent enough). The exhaust shop will use a bit of straight pipe as well to make up the gap as stock secondary cats are significantly longer than the high flows.

hope that helps,
~AMS~

 

I ordered a 2.5" pipe from DHM Performance for an exhaust cutout and when I went to the exhaust shop, they told me that the pipe wasn't going to fit and that it looked like the pipe under the car was almost 3".

 

I just installed mine yesterday ! 2.5 inch fit prefect

The sound improvement is small but noticeable nice improvement
suppose to give 10WHP... humm don't fell it

overall :

 

you installed it on your clk55?

I have a buddy who has bypassed his clk55 muffler and went straight pipe from cats back and it sounds VERY aggressive.

any pictures?

 

I had my silencer removed and swapped for a straight piece of pipe.

I am very happy with the vocal improvement.

Sounds alot more aggressive when under load, and civilised when cruising.

I noticed alot of difference in the sound when I kick the throttle over while sitting at traffic lights.

It has a lovely rough note to it.

Pops and booms loads as well!

LOL

 

clk63 has a resonator? how come the clk55 doesn't have one?

 

I don't know why the clk55 does not have a res. My 04 CLK55 is not loud at all with: AMS headers, 300 cell 2nd cats, (No res from factory), stock AMG muff, single exhaust. I'd actually like it a little louder. I guess next step would be aftermarket muff?

 

I've always heard that the AMG mufflers/ backboxes are best, and that you should keep them on. They are best for sound quality.

Things may have changed now though.

On the subject of why some AMG's have mufflers and some don't, I noticed something interesting the other day when I was in the showroom...

I was looking at a new C-Class (not to buy.. just looking!) Anyway, they now seem to be offering "Optimised Sound" as an extra!?

I'm guessing that MB/ AMG are going down the same route as us lot - altering the exhaust system in various ways to create sounds to suit the customer requirements.