[Patel151]

Hey guys, so I have a dilemma with my F30 and I'm not sure what exactly the case is here. I'm currently running VRSF Catless & Magnaflow Muffler w/ BM3 and I'm getting some unusual bogging/vibrations in the downpipe area.

I got my downpipe installed a couple months ago and I had no issues. Just recently after a snow day, I was driving in slush and the car started making this obnoxious bogging noise/vibration from the downpipe area on and off. One minute sound would go away, then after some time the sound would come back for some time and go away again. Now most of the times, whenever I drive over bumps and uneven roads, the sound would come back.

I'm suspecting that the exhaust may be touching the sub frame or something may be loose/leaking exhaust but I took it to a mechanic and they found nothing. So, any clue what this could be?

Here's a link to a short clip of the sound:

The car was in Eco mode in this time so the noise can be heard much more clear. It's like a combination of drone/vibration/bogging and I can't pin point the exact problem. When I put the car in sport+, noise can still be heart, more faint... yet still annoying. Driving in sport mode, when doing a small pull, the exhaust tone isn't smooth like before, because now you can feel a vibration or unusual drone that comes and goes before gear changes.

[floridaorange]

I'd definitely have an exhaust shop look at that.

[bgalakazam]

I can't tell what's going on but I had a very annoying metal on metal vibration after the vrsf install. Had to remove the metal bracket that was connected to the transmission and also make sure the first connection point after that was aligned and the 2 bolts connected. Initially it was just hanging. I had no leaks either way.

[Patel151]

Just an update, I ended up having to rotate the downpipe. I guess when in drive, there is load on the car, which causes metal to metal vibrations from time to time. Loosened the V band clamp and mid-pipe to dp clamp, rotated the downpipe and fixed my issue.