tdi chatter?

[dannyjb]

hi, i was driving down th road th other day & a golf gt tdi came past me n it chatterd/dumpd.

what dumpvalve/kit do you need to make this? he said he didnt know what dv it was, all he knew it was remapped with decat and full system.

oh n ano its a diesel bt.. i like this noise

 

[jameshughes1974]

They don't have a dump valve as such.
It's the variable vanes aka the vnt in the turbo moving position in response to request for less boost or foot coming off the accelerator pedal in a fast gear change.
I believe mapped tdi may be more prone to this as some maps have more boost lower down the rev range.