Turbocharger
A turbocharger is an exhaust driven pump and compressor that increases air intake volume. 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 driven by the expanding exhaust gases is fastened to a common shaft that drives the compressor wheel. 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 it opens to divert 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 damage vital engine components. When manifold pressures reach their maximum, the wastegate opens depriving the turbine of exhaust and allowing the compressor wheel to slow. This reduces boost pressure. Once boost pressures are under control and reach normal the wastegate will close.
Turbocharged engines are different than normally aspirated engines. They have a lower compression ratio, 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 the common shaft ride on spin at high speeds and will overheat or become damaged very quickly. One of the symptoms of a bad 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
Another important check is to make sure the air tube is not obstructed or collapsed. Also make sure no foreign debris or dirt is sucked into the intake by keeping the air filter clean. Maintaining correct oil levels and changing oil and air filters at regular intervals is a matter of common sense with all vehicles and even more so with a turbo charged engine.
