two-stage turbocharger (bi-turbo) Cutaway are: both turbochargers, control flaps and the fresh-air valve. The turbines and throttle valves can be moved. Exhaust air, fresh air and oil channels are accentuated in colour. description ordernumber 1327 see also: air-flow sensor with platinum heating filament VP 44 (Bosch) radial-piston distributor-type injection pump cylinder head with swirl chamber cylinder head with direct petrol injection (GDI)