Strange sounds from my tdi...
When im in a low gear (usually 2nd or 3rd) at low revs and then put my foot down for a few seconds then come straight off the accelerator again, sometimes I get the usual quiet 'tshhh' from the dump valve/wastegate whatever you want to call it.
Sometimes though it makes a sort of chattering noise that doesnt sound too healthy instead. It usually makes this noise lower in the revs when coming off the accelerator.
i have the same sonund,
i have a 140bhp tdi on a 53 reg, i have noticed this for a while now, im very sure there is nothing wrong, it is just the air from turbo being dumped, i think these tdi's have whats called a recirclating system and the noise you can here is the air hiting the turbo blades (this is normal)
i have fitted a green cotton air filter that replaces the standarded box filter, the noise is louder as the filter breaths better
very sure there is nothing wrong with your car
Audi a3 facelift 2011, 19" wheels, s3 side skirts, bkd 163k