Quote:
Originally Posted by Newb17
I want a noticeably louder exhaust than factory, all around. If there's some drone with the bypass, I'm ok with that. What I'm really wondering about is the volume difference between the 4 pipe and bypass. If there's very little difference, I'd go with the 4 pipe.
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Between 4 pipe and bypass (ACM) is very little difference , almost none.
With the 2 big and all 4 perforated pipe replacement method, the Helmholtz chambers are still intact and functional .
Helmholtz chambers are designed by BMW and are anti-drone and unique because our Oem exhaust is a very good exhaust and also double walled .
With the bypass or ACM method the Helmholtz chamber function is deleted because the pipes going now straight through and so the exhaust will drone at low rpm's .
My thread because I've done this mod. by myself =>
http://www.m3post.com/forums/showthread.php?t=733817
There is also something like sound quality ..And for me personal the bypass sounds like a broken exhaust with lack of sound quality ,while the 2 big or all 4 method just sounds amazing .
In the video you can hear the 4 pipe method...