I guess first F15 X5 50i OEM exhaust mod attempt....

[Cbozz]

So out of boredom I went ahead and cut my OEM muffler open - it's a 50i M sport muffler. It actually sounds good all stock but I wanted a little more sound. I also have e92 m3 with a fulle exhaust and it's a screamer I figured people were doing OEM mod and that sounds great so why not give it a shot...
I ended up cutting it open but got stuck there, if you look at the picture the dead end pipe is 3" wide and it would elbow into the perforated one but that one is 2.5" so after all I ended up packing the fiberglass back in (fiberglass was only in the middle baffle), welding it all shut and it's back on the car... Honestly if I were to replace the 2.5" perforated pipe it would end up being a straight piped muffler... I tried that and used a straight pipes instead of muffler but it was way too much drone and the crackers and pops that you can hear sometimes were pretty bad - sounded like my luxurious X5 was taking a shit while flooring it... I ended up welding the muffler back on and wishing I never started this because I wasted all day just to be back where I started.... oh well. I hope this helps...

[PNWN54]

I’ve been searching and wanting to the same to my 50i stock exhaust as well. Really interested to see your result. I’ve had OEM BMW performance exhaust on my N54 335i before and also done PE mod to stock exhaust for comparison and I loved the modified exhaust version more because you get the option of valved exhaust. Only issue I see with the X5 exhaust is that the valve system is a little bit more complex but nothing you can’t modify or alter. This to me is probably the best exhaust setup by far. It’s really aggressive in tone without the boomy and drony exhaust system like the muffler deletes and etc.
But....this setup is very loud with downpipes and by no means subtle without either. I would keep all the resonators for that reason if you go catless or at least an X pipe in place.

[PNWN54]

Can you take some more pictures please? Trying to see what perforated pipes to actually replace.

[Cbozz]

Originally Posted by PNWN54

Can you take some more pictures please? Trying to see what perforated pipes to actually replace.

this is the only picture I took. the thicker perforated pipe is coming from the car and it dead ends and sound waves break up going around and into the helmoltz chamber and perforate pipe to the exhaust tip... this is from 50i and my car didn't have valves and I'm not sure if any of 50i has valves and only 35i has those...
it's hard to alter this since the pipes don't connect and also one is 3 inch and one is 2.5 inch...

[PNWN54]

Haha never looked at exhaust yet, might need to get under there. Lol

So what you’re saying is this? The perforated pipe that dead ends is 3” and the perforated pipe that connects to a solid stainless steel pipe is 2.5”? Just trying to confirm what to tell the muffler shop to weld together with a solid stainless steel pipe. Might need to do a reducer form a 3” to a 2.5” to make this work.

My only concern is now knowing there’s no valve to keep one side closed for the wife and babies.
It will be quite loud with this modification, might just go with catless downpipes to enhance the sound instead.

[PNWN54]

Unless I can only modify one side to have a straight pipe in the muffler.

[pennsiveguy]

There's an extensive 50i muffler delete thread.

[PNWN54]

Originally Posted by pennsiveguy

There's an extensive 50i muffler delete thread.

Looked at all 29 pages. No one has modified the stock muffler box. Lol

[pennsiveguy]

Originally Posted by PNWN54

Looked at all 29 pages. No one has modified the stock muffler box. Lol

Probably because it's easier to cut it off and put something else on. And when we're done playing "zoom-zoom" we can put the muffler and tips back on and bring the car back to stock; you can't easily do that once you've hacked the stock muffler to bits.

[hufington]

Originally Posted by pennsiveguy

Probably because it's easier to cut it off and put something else on. And when we're done playing "zoom-zoom" we can put the muffler and tips back on and bring the car back to stock; you can't easily do that once you've hacked the stock muffler to bits.

+1

Also the OEM rear muffler is very heavy.

[PNWN54]

Originally Posted by pennsiveguy

Probably because it's easier to cut it off and put something else on. And when we're done playing "zoom-zoom" we can put the muffler and tips back on and bring the car back to stock; you can't easily do that once you've hacked the stock muffler to bits.

Totally understand and each persons situation is different. I’m planing on supplying another OEM muffler for the hacking.

Also, planning to add an X pipe after the resonators to divert some of the air flow. But don’t think extra packing within the muffler is necessary tho.