Tuesday, November 6, 2012
Car care: turbo basics and tips
A turbocharger is basically an air pump that drives a volume of air into the engine, thus increasing performance and fuel economy. A fan in the exhaust system drives the air pump of the turbo by a direct shaft. The volume of air that is pumped into the engine is in direct relation to the volume of exhaust that flows out. A wastegate in the turbo unit regulates the pressure to prevent an over-boost from damaging the engine.
As the turbo pumps and compresses the air into the engine, the air is heated up. To cool the air, an intercooler is needed and is installed either behind or next to the main radiator. Some turbo units are further water-cooled by the coolant system via a system of connections. This feature ensures that the turbo temperature does not rise higher than that of the cooling system. Turbo units may reach speeds of 100,000 rpm so it is vital that it is fed with enough engine oil when it is running.
Contaminated or insufficient engine oil is a common cause of turbo failure. Another cause is when heavy particles enter the air stream, so a clean air filter and ducting is equally important. A third cause of failure is when objects like pieces of rust and hard carbon break off and leave through the exhaust system.
Some tips are given below to prolong the life of your turbo:
(1) Change your engine oil after every 5,000 km. If you drive mostly in the city, an oil change every 3,000 km is recommended. Make sure the filter is also changed when an oil change is made.
(2) Use the best possible engine oil that you can afford. Though petroleum-based oils designed for high performance cars are good enough for turbocharger applications, synthetic oils are even better. The latter can withstand extremely high temperatures without breaking down.
(3) A turbo is still spinning after the engine is switched off. When this happens, the turbo will not be getting any oil and the bearings can get damaged. To avoid this, after normal driving, before switching off the engine, let it to idle for 10-15 seconds. If the car has been driven hard and fast (such as after an outstation journey), then let it idle for as long as two to three minutes.
(4) Change the oil feed line after every 80,000 km.
(5) After you start the engine, let it warm up and do not rev it immediately as
the turbo has yet to receive an adequate supply of oil.