Today had secondary cats and resonator removed.
I do still wanna check for any stored codes as the car seems to as though it may have actually lost just a touch of power.
There was a problem though, After they already cut the exhaust we found it was 2.75" and not 3" and they can't even get that size piping. So, from the primary cat's it's the stock 2.75" to the point where the secondary cat's used to begin and then changes to 3" mandrel bent down to where the resonator used to end and changes to stock 2.75" piping again out to the mufflers.
I figured because it finishes in 2.75 it shouldn't really kill too much back pressure and removing the secondary cat's would maybe even give it a slight increase in feeling.
The car doesn't even seem to have so much of a problem with wheel spin in
1st lately and it usually did. It may seem a little stronger in the higher revs and I'm not even sure about that.
I'm gonna check for any codes tomorrow at the dealer when I get my oil change
Last edited by Sean03S55; Jul 6, 2007 at 08:05 AM.




I found 2.75" piping and mandrel bends on ebay. I wonder if it would be worth changing to so it's the same diameter all the way through. I doubt that 3" section is really hurting performance though. I have to get it back on a lift and make sure there are no leaks at the welds, I don't know if I like this exhaust shop too much.
It's only the first day driving since the change, if it doesn't get any better maybe I'll put the cat's back in and just leave the resonator out but this time order some 2.75" piping.
Last edited by Sean03S55; Jul 6, 2007 at 08:07 AM.
Just my opinion........
Just my opinion........
What do you guys think, I should just return the cats and get 2.75" for the resonator section? Or if the loss isn't even because of removing the cats but from using the 3" section.
Last edited by Sean03S55; Jul 6, 2007 at 05:06 PM.
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If it were my car,I would put everything back on&wait for good quality set of equal length headers&a full exhaust designed specifically for the 63.
But even with that,unless the car is able to breathe better I dont think the exhaust would be worth more then 15-20hp and cost thousands of dollars
The Best of Mercedes & AMG
Just my opinion........
Of course, that's within limits as well. A poorly made low restriction exhaust will reduce power, but just pulling off a few things off a stock setup isn't that dramatic.
I can't believe I didn't do this earlier, it's awesome!
Highly recommend for anyone who wants more low end growl and bark in the exhaust. Sure, it's not as refined as the AMG exhaust but it's way better than stock.
Removing the resonator opens up more flow so you get a more/louder sound, then you can fine tune the note from there.
Stop thinking about it and just do it. If you don't love it you can add an x-pipe or new mufflers and adjust to your taste.




Any check engine lights or codes pop up for those of you who had the secondary cats removed as well?
Please let me know.
Thanks!



