The Turbochargers Function
A turbocharger is an exhaust driven compressor that increases air intake volume. A turbocharger improves engine performance by compressing the charge into the combustion chamber. This improves the volumetric efficiency of an engine. Because a turbocharger is driven by expanding exhaust gases unlike a supercharger that is driven by engine power, it is said to be a free source of power boost.
A turbine wheel and the compressor wheel are attached to a common shaft. The turbine wheel is forced to spin by the expanding exhaust gases while the compressor wheel compresses the air fuel charge in the intake manifold. This compressed charge is denser in comparison to a conventional engine that relies on the downward stroke of a piston to create low pressure or vacuum in the intake manifold. The denser charge is forced into the cylinders by the increased intake manifold pressure to provide additional engine horsepower.
A turbochargers output is controlled by a wastegate diaphragm or bypass valve that opens and closes a wastegate. It controls output by diverting some of the exhaust away from the turbine depriving it of its source of energy. Without this necessary reduction in output manifold and cylinder pressures would increase to a limit that will damage vital engine components. When manifold pressures reach their maximum which depends on the charger, the wastegate opens allowing the compressor wheel to slow and reduce output pressure.
Turbocharged engines are different than normally aspirated engines. They have a lower compression ratio, they are port injected, and the parts are usually not interchangeable. A lack of maintenance is typically the cause of premature failure. Turbocharger failure will surely effect an engines performance.
Most turbocharger failures are oil related. Contaminated and unchanged oil will result in bearing damage. The bearings spin at high speeds and overheat and become damaged quickly. One of the symptoms of an oil leak in a turbocharger is blue exhaust. This is because as the turbo fails oil is mixing in with the air fuel charge and burning off in the cylinder. Turbochargers are usually cooled by the engines cooling system. Always make sure the cooling system is maintained and functioning properly
Check is to make sure the air tube is not obstructed or collapsed. This will deprive the charger of vital air flow. Also make sure no foreign debris or dirt is sucked into the intake by keeping the air filter clean. Today's turbochargers spin well over 100,000 RPM. It is vital to maintain lubrication or the bearings will fail resulting in metal and brass shavings in the oil stream.
