OE Exhaust Mod: 1.5, 2, 2.5, 4 pipe

[GtiGyver]

I currently have the BMW PE v1 exhaust. I find it very quiet, even with the primary cat deleted. I also find it too metallic sounding.

I was wondering what the differences were between these different levels of mods of the original exhaust. I can't find any definitive answers on any forum.



Looking at this picture.
There are 4 areas with vented pipes and 2 Helmholtz resonators.

What is the 2 vs 4 pipe mod?
What makes the x.5 version?

Thanks

[wfdeacon88]

Originally Posted by GtiGyver

I currently have the BMW PE v1 exhaust. I find it very quiet, even with the primary cat deleted. I also find it too metallic sounding.

I was wondering what the differences were between these different levels of mods of the original exhaust. I can't find any definitive answers on any forum.

[IMG]https://www.m3post.com/forums/attach...1&d=1504653250[/IMG]

Looking at this picture.
There are 4 areas with vented pipes and 2 Helmholtz resonators.

What is the 2 vs 4 pipe mod?
What makes the x.5 version?

Thanks

2 pipe - replace two largest vented / perforated pipes with solid pipes. (some wrap them instead of replacing)

4 pipe - replace all perforated pipes with solid pipes

"ACM" - bypass the inner muffler chambers and Straight pipe from back to tips. (essentially muffler delete, but with OEM muffler weight)

I had the 2 pipe mod, with cat delete, it was good. but probably similar to the MPE somewhat in tone. I swapped to a Corsa with TPs. perfection.

[GtiGyver]

Thanks wfdeacon88.
That explains it perfectly.