[JakeW1990]

Weird rattle coming out the end after DP’s that I don’t recall having last time. Motor sounds great with no issue so not worried about rods, sound isn’t persistent and only hear it at idle. I’m thinking wastegate rattle?

Idk how to post videos so link is to Facebook M5 group where I posted them. Maybe that works…

https://www.facebook.com/groups/2538...ibextid=W9rl1R

[pbonsalb]

I have a sound that may be similar. I believe it is the stock rear exhaust valves vibrating on one side or both sides due to the extra flow. I have been meaning to look more closely at this — maybe disconnecting or removing the valves would help. Some people have said that the stock valves are never fully opened by the controller—that could be the problem.

[JakeW1990]

Originally Posted by pbonsalb

I have a sound that may be similar. I believe it is the stock rear exhaust valves vibrating on one side or both sides due to the extra flow. I have been meaning to look more closely at this — maybe disconnecting or removing the valves would help. Some people have said that the stock valves are never fully opened by the controller—that could be the problem.

I can hear it it all the way back up near the primaries at times and it’s about the same loudness from what I can tell. It comes from both sides so it’s not isolated to one bank. Seems harmless but figured I’d see if anyone else had the same noise. The valves would be a good test.

[pbonsalb]

If up front, I would be concerned the DP were not properly installed. One person recently commented that one brand lacked mounting brackets. You don’t really need the lower primary brackets — the uppers are enough, but you do want brackets in the secondaries. I installed mine myself and have a lift so I know exactly what I have and what any issues might be.

[JakeW1990]

Originally Posted by pbonsalb

If up front, I would be concerned the DP were not properly installed. One person recently commented that one brand lacked mounting brackets. You don’t really need the lower primary brackets — the uppers are enough, but you do want brackets in the secondaries. I installed mine myself and have a lift so I know exactly what I have and what any issues might be.

I installed mine this time and last year on my other M5. Vbands are all sealed with no leaks and all mounting brackets were utilized, albeit I installed mine from the floor on ramps and jackstands both times. 😆 I’m going to try and borrow someone’s lift in the neighborhood to install some carbon fiber pieces when they get here and I’ll re-check alignment and so forth. It’s just a tinny/metallic pop consistent on both sides. Could be differences in the fat boy versus regular MAD DP’s and their acoustic differences.