Those who replaced centre resonator with X-Pipe......

[PenttisHSR]

Any chance one of you could cut open the box you removed, would love to see what's inside.
It's the box with 2 pipes in and 2 pipes out.
I already cut open the rear silencer/muffler, found a resonator in there.

[cjw]

Interested.

Post pics of the mufflers cut open.

[PenttisHSR]

Interested.

Post pics of the mufflers cut open.

Look in "My photo Gallery" for rear mufflers.

[cjw]

Cool. Looks like they are pretty straight flow through. Curious on the center one.

[Victor Newman]

looks like it goes in through the red circled pipe to the rear of the muffler, then flows forward through perforations in the two separating plates, then back through the two pipes where the tips are right?

[PenttisHSR]

looks like it goes in through the red circled pipe to the rear of the muffler, then flows forward through perforations in the two separating plates, then back through the two pipes where the tips are right?
NO! - The rear of the muffler has no holes, it's a sealed chamber. That section is acting as a Helmholtz Resonator.
That's why it drones bad if you replace the muffler with a straight through design.
I added a 1/4 wave resonator tube (J-Pipe) to my custom muffler.
The rear muffler is not just a muffler, it's also a resonator.
Anybody cut open the centre resonator yet? Would love to see what's in there.

[Loe]

similar to my E90 M3 days with what they called an "oem exhaust mod" where they replaced the perforated section of the OEM muffler with a straight pipe, but kept the OEM Helmholtz design. You get a loud exhaust, without the interior boom. Thanks for posting the picture in your gallery, gives me a few ideas myself.

[Victor Newman]

ah, i see now. it is straight through with the red circled pipe open to the body of the muffler. so they look like they have no restriction at all as far as flow goes, and they're really just helmholtz chambers. nice design - glad i'm keeping them now