X2Board

Well, I decided to hear for myself what others have been saying, and had the rear cats and resonator removed. The car does have a slightly louder sound, no drone and a bit of a burble on deceleration. I'm pleased with the results, but will probably do mufflers at some point.

mprsev

Looks good. I sure wish I could get this done but no one wants to remove my secondary rear cats!

AWOL

feel a loss of power?

komp55

That's because it's illegal to do so and shops generally aren't willing to risk the fines and other potential consequences for unknown customers. Lots of guys have had it done though; ask around and find out what shops in your area are more mod friendly.

X2Board

I have not driven it enough to notice, it went directly to the dealer to have the camshaft and crankshaft position sensors replaced, and it was only 3 miles away from the exhaust shop. I'm hoping it's done today, so I don't have to drive the 212 E350 all weekend, the interior of that car is depressing, and Camry drivers keep giving me the nod, until they see the hood ornament. The rental Chevy I'm driving on my business trip has a nicer interior

HeissRod

I had a base model C300 for my loaner last week. Now that was depressing & uncomfortable.

Forrest Gump 9

Shouldn't be, he had the x-pipe and primary cats. When I installed my long tube header I had my secondary cats removed (no cats in the car but still have the resonators). That resulted in major low-end power loss. I lived with that for a whole three days. Went back and had hi-flow cats installed (car with no cats smell horrible) and also added the H-pipe. All is good since then.

HeissRod

Do you have to remove the secondary cats when you do an x-pipe set-up in place of the resonator?

chawkins2001

If you add the x pipe where the resonator is placed, no you dont. Typically the x pipe should go close to the motor so the exhaust pulses can merge together, so most install the x pipe where the secondary cats are.

HeissRod

I just don't want to hav to deal with fudging a state inspection every year. I've done that with my last two cars and I'm just tired of the headache.

komp55

Of course the factory exhaust already has a crossover H-pipe in this location ahead of the secondary cats. With four cats, an H-crossover in front of the secondary cats, and another crossover within the factory resonator, the stock exhaust system sure seems highly engineered . . . probably why exhaust mod power gains are so hard to come by without doing LTs or butchering the factory cats.

X2Board

The stock manifolds are highly engineered fail! They took the cheapest route there.

komp55

Well, the post was about X-pipes, not the exhaust manifolds, but I definitely agree with your assessment of the manifolds. That's why I installed Evosport shorty headers some while back:

https://mbworld.org/forums/w211-amg/...r-install.html

X2Board

That is what I need to do next.