[StackedM2C]

Hey guys,

I know this is a really commonly done thing in the UK by PCW exhaust mods
.
I am in Canada and theres not much information on getting this done.

For reasons that some people may know, it is essential to appear "stock"

has anyone done this before ?

i have referenced a few photos below of the f80 factory exhaust cut open.

does anyone know if the m2c is similiar and which locations to block off for a 10-15% sound increase? the outer hexagon shaped perforation holes on the edges (far left and far right) or just the perforated pipe in the middle.

thank you!

[M3R1]

Having done my E92 M3 back box myself, It is worth a try if volume is your goal. I cut mine open, covered only a portion of the pipes and rewelded it shut. In order to make a louder stock looking rear section you need to cover the perforated holes. I covered a little more than 50%, this let some exhaust escape, kept the volume down and there was zero drone. I realize these are different engine and exhaust set ups, however the theory is still the same. I say give it a try...

[StackedM2C]

Originally Posted by M3R1

Having done my E92 M3 back box myself, It is worth a try if volume is your goal. I cut mine open, covered only a portion of the pipes and rewelded it shut. In order to make a louder stock looking rear section you need to cover the perforated holes. I covered a little more than 50%, this let some exhaust escape, kept the volume down and there was zero drone. I realize these are different engine and exhaust set ups, however the theory is still the same. I say give it a try...

thats awesome, thanks for the insight! yes i am looking for volume only.
Im just wondering if i should open up the edge or the middle, but i have a feeling i might end up doing both.

if anyone else has done it , please chime in!!

[M3R1]

Originally Posted by StackedM2C

thats awesome, thanks for the insight! yes i am looking for volume only.
Im just wondering if i should open up the edge or the middle, but i have a feeling i might end up doing both.

if anyone else has done it , please chime in!!

Judging from the pics in the OP and dissecting my OEM E92 back box, I would bet the middle is where you need to start.

[VisualEcho]

Originally Posted by M3R1

Having done my E92 M3 back box myself, It is worth a try if volume is your goal. I cut mine open, covered only a portion of the pipes and rewelded it shut. In order to make a louder stock looking rear section you need to cover the perforated holes. I covered a little more than 50%, this let some exhaust escape, kept the volume down and there was zero drone.

I've seen this done, and considered it for my own exhaust.

This thread details it pretty well.

https://f87.bimmerpost.com/forums/sh....php?t=1410712

[M3R1]

Originally Posted by VisualEcho

I've seen this done, and considered it for my own exhaust.

This thread details it pretty well.

https://f87.bimmerpost.com/forums/sh....php?t=1410712

In the video in the thread you attached (as well as others) you will see that many people replace the perforated section with a solid section. My technique was a little easier. I used aluminum sheets and cut them to cover only the portion I wanted, then used stainless band clamps to hold the aluminum in place. Lastly I welded the clamp so it would never come undone. I did not want it as loud as it would have been without all of the perforations blocked or replaced with a solid pipe.

[inTgr8r]

Originally Posted by StackedM2C

Hey guys,

....

For reasons that some people may know, it is essential to appear "stock"

Not sure why you are worried about "appearing stock"
Aftermarket sound ordinance or dealer warranty??

[VisualEcho]

Originally Posted by M3R1

In the video in the thread you attached (as well as others) you will see that many people replace the perforated section with a solid section. My technique was a little easier. I used aluminum sheets and cut them to cover only the portion I wanted, then used stainless band clamps to hold the aluminum in place. Lastly I welded the clamp so it would never come undone. I did not want it as loud as it would have been without all of the perforations blocked or replaced with a solid pipe.

The way you did it is probably best, as it allows it to be returned to stock in the event you don't like it.

The way the guy in the M2 thread did it (I'll call it the standard way), it effectively straight-pipes the exhaust, making it almost identical to the Fabspeed muffler bypass system. That might be a little much for me, so I'm considering blocking off just one of the chambers instead of them both. I think it's probably best to do the larger chamber.

[M3R1]

Originally Posted by VisualEcho

The way you did it is probably best, as it allows it to be returned to stock in the event you don't like it.

The way the guy in the M2 thread did it (I'll call it the standard way), it effectively straight-pipes the exhaust, making it almost identical to the Fabspeed muffler bypass system. That might be a little much for me, so I'm considering blocking off just one of the chambers instead of them both. I think it's probably best to do the larger chamber.

Wow, great illustration!!!

You are definitely a man of many talents...