3308486 - 1064A turbo charger assembly
GARRET T25 TURBOCHARGER
It basically consists of two impellers fitted on the same shaft which rotates on two special bearings which are lubricated by means of two branches in the engine lubrication system.Two special pipes from the engine cooling circuit are connected to the turbocharger and have the task of dispersing some of the large amount of heat which is given off by the exhaust gases at the turbine.A "turbine" impeller (3), connected to the exhaust manifolds, is made to rotate by the energy of the exhaust gases directed to it.The turbine causes the other "compressor" impeller (4), connected to the air chamber, to move at the same rotation speed.On account of its rotation speed and the particular shape of the vanes, the compressor draws in outside air and compresses it.If the engine speed increases, the rotation speed of the turbine and the turbocharger also increases and so too does the quantity of air supplied to the engine.There is a wastegate valve (2) fitted on the turbocharger which, through the operation of a "Pierburg" supercharging pressure control solenoid valve, allows some of the exhaust gases to by-pass (or not by-pass) the turbine according to the engine power/torque requirements.