captainsmelly

i'm looking at a calibra 4x4. under full boost you can hear quite a loud howling sound through the exhaust. its quite different from the normal induction roar and exhaust noise. the owner tells me that its just because of the exhaust being a full powerflow system, the normal turbo whine/whistle is not muffled. i've driven a couple of mitsi evos and not noticed this level of sound before. it is only apparent on hard acceleration, full boost.
there is no smoke coming out and it runs very quietly under all other circumstances. i am just concerned it may be a sign of an air leak which would be not so bad, or wear in the turbo bearings which would be more bad.
btw apart from the zorst, the car is standard. standard air box, no raise in boost pressure.
any ideas?