Metal Ting noise

[Lzar16]

Can anybody help, whenever I accelerate or take my foot of the pedal in comfort mode or sport mode there seems to be a metal ting sort of noise I can here it with the windows and roof down either coming from the front or rear I'm not sure if its the flap inside the exhaust looks fine any help much appreciated
Z4 E89 Msport 18i :?

 

[Jembo]

A video or sound clip would really help

 

[Lzar16]

Yes I will take a video tomorrow and post

 

[Felixlamb]

I have something similar with my 20i. Pretty sure it's the flap in the exhaust either opening or closing. In comfort it happens if I put my foot down a bit. It will also make the same noise when transitioning from comfort into sport (as I believe the flap is always open in sport?), and will do the same going the other way. IMO it's just the exhaust flap so shouldn't be anything to worry about.