I have heard "turbo surge" on Lee's (porkie) 3dr round bedford. He was accelerating hard and the turbo was chattering/fluttering a good'un when i asked him whats the chattering noise he said "fuck knows, i'll ask Martin"

But it was confirmed as turbo surge, and i noticed it disappeared once you got over 4K+ rpm as the engine was consuming all the air the turbo was producing.