turbo is over spinning
Hi Chaps,
This noise is the turbo over spinning and eating the bearing. These turbos only use the old style technology bronze bearing which will be eaten if the turbo goes out of balance due to over revving. I killed a KO3 sport in the same way, i think your turbo's are the same or KO4. Take the inlet hose off the turbo and see how much play is in the shaft of the turbo. You will have a tiny bit of play due to no oil pressure which these bearing rely on. Anymore than 1-1.5mm and the bearing has had it, also check the inlet "snail" for marking from the impeller blades.
Good luck
J