Thanks to a good filling factor, an increase in engine power of up to 100 percent is achieved. The increase in power depends, among other things, on the pressure that is present in the engine of a passenger car, amounting to from 0.4 to 0.8 bar (for comparison, tire pressure is about 1.8 bar). When the pressure set at the factory is exceeded, the safety valve opens to release excess pressure.
Along with the increase in power, the use of a turbocharger allows for an increase in torque, which is particularly desirable from the point of view of the flexibility of the engine. However, the condition for this is the speed at which the turbocharger shaft rotates and thus guarantees the required filling factor. As a rule, a noticeable increase in pressure occurs starting from an engine speed of 2500 rpm.
Compared to petrol engines, diesel engines do not require a reduction in the normal compression ratio due to additional compression, so that the injected fuel is fully utilised even in the low speed range.
The turbocharger is a unit of extremely precision manufacturing. Therefore, it is recommended to entrust its repair only to a qualified specialist. As a rule, if the turbocharger is defective, it is replaced as a set.
The exhaust gas turbocharger is supplied with oil from the engine lubrication circuit. To ensure sufficient lubrication of the turbocharger, the following points must be taken into account:
Fill only with prescribed grades of oil.
Do not run the engine at high speed until engine pressure has built up and the indicator light has gone out.
After changing the oil, do not start the engine immediately, but only after turning it for some time with the starter so that the oil can get to the lubrication points. To prevent the engine from starting, disconnect the wire from the shut-off valve. The same should be done after the car has been parked for a long time.
The supercharger may become coked from old oil. Coking of the supercharger shaft is noticeable after removing the oil line. In such cases, it is necessary to replace the oil and oil filter.
Even the smallest particles of dirt can damage the supercharger; never start the engine without an air filter.
A hose disconnected from the control valve can cause overload when full throttle is applied and consequently damage the engine.
(The original text is available on the website www.bmwman.ru)