Exhaust rattling

[twilly12]

M4 I just got my m4 back and I noticed that it’s rattiling with the valves shut and open I also have no burbles or pops at all. How should I fix both of the issues? I took to exhaust shop he sayed it’s something with the valves but that still doesn’t explain why it’s not burbles. I don’t know if the car has a tune or not.

[Boznien]

Your valves may be compromised. My friend had to weld his valves open because the rattle was unbearable. (Granted his car is a 2016 Audi S3) but I imagine the valve concept is the same.

Is your exhaust stock?

[louielouie]

Exhaust rattling can sometimes be caused by springs becoming looser over time. This can be in stock in which the springs is inside a cylinder underneath the valve controller or a thicker connecting butterfly spring commonly used on aftermarket applications.

In terms of the burbles - not sure about this. Odd both are happening at once but inclined to suspect they're separate issues.

[twilly12]

Originally Posted by Boznien

Your valves may be compromised. My friend had to weld his valves open because the rattle was unbearable. (Granted his car is a 2016 Audi S3) but I imagine the valve concept is the same.

Is your exhaust stock?

I have no cats and after market tips and down pipes so I’m not to sure I didn’t do myself and haven’t had on lift to look.

[Boznien]

Originally Posted by twilly12

I have no cats and after market tips and down pipes so I’m not to sure I didn’t do myself and haven’t had on lift to look.

You can actually turn the burbles on and off with an app called 'Bimmerlink'

I used it on my F80 to switch them on and off whenever I wanted. I'll link a video from Tommy L Garage who has a step by step tutorial on how it works.

Tommy L Garage Burble Video

Super simple but easier to follow a video than text on a screen.

[Niart906]

I had a similar issue a few years ago. In my case the passenger valve actuator had failed. Remove them from the muffler one side at a time and see if the noise disappears. These actuators are about $130 from FCP last I checked.

I bet the burbles are a separate issue, can't imagine they're related.