Turbocharger

[Neilchua]

What is a turbocharger?

A turbocharger is an exhaust gas driven supercharger. Exhaust gas from an engine is used to drive a turbine connected by a common shaft to a compressor. This compressor in turn is used to supply air under pressure to the engine, which combined with the correct amount of fuel has the effect of increasing the output of the engine over that of an engine of equal size without a turbocharger. The amount of this increase can vary considerably from 10% too as much as 500% in some isolated cases.

 

 

What oil and how often should it be changed?

Turbos must have good quality oil. Use oil that meets the MIL specification for a turbocharged engine. Change oil at intervals recommended by the vehicle manufacturer.

 

Can I fit a turbo from another car?

Generally no, virtually all turbochargers are different inside, even if they appear similar on the outside. The turbo model e.g. Garrett T3 or, Mitsubishi TDO5 is only the model, not the specification.

 

What is a hybrid turbo?

A turbocharger that is a specially built combination designed for quick boost response required at low engine rpm, with the extra airflow capacity needed for more power at higher revs.

 

Can the boost pressure of my turbocharged engine be increased?

Only if the engine has been modified to accept these changes without forsaking reliability. e.g fuel system, computer engine management, exhausts and intercooler.

 

Why balance a turbocharger?

Without highly accurate balancing, vibration will create a whining noise, reduce turbo-component life and reduce turbocharger efficiency.

 

What is boost pressure?

Boost is the pressurized air supplied by a turbocharger to an engine - this is often referred to in a number of units, all meaning the same thing eg Bar, PSI Kpa - all units of pressure.

 

How many psi in one bar?

14.7 psi = 1 bar.

 

What boost pressure should I run my turbocharger at?

This will vary for every different car and manufacturer. Seek their advice before adjusting.

 

Are all actuators the same?

No, each has a different opening pressure and rate.

 

What is a blow off valve?

A valve that relieves backpressure between the compressor outlet and engine as the throttle is closed. Only sometimes required on engines producing in excess of 14psi-boost pressure.

 

What is a bleed "T" valve?

A bleed valve reduces the signal pressure to the actuator wastegate. It in effect increases the boost pressure by fooling the actuator. Refer to Can the boost pressure of my turbocharged engine be increased?.

 

 

Oil in the turbo inlet pipe - Should I be concerned?

A small amount of oil usually exists, drawn in from the engine's crankcase breather system. High engine wear will increase the amount of oil found, and will require further engine tests (not turbo).

 

Can I fit a high-flow air filter?

Yes, but only if the quality of air filtration is no less efficient than the original manufacturers filter. Poor filtration will cause the turbo compressor blades to wear, resulting in reduced turbo efficiency.

 

Why is my car smoking at the traffic lights?

One of the typical early symptoms of a turbocharger problem is a blue smoke haze being emitted from the exhaust whilst the engine is idling over.

 

How noisy should a turbo be?

An unbalanced, worn out or damaged turbo will produce significant turbo noise. Other possible causes are loose air hoses, broken manifold studs or leaking manifold gaskets.

 

What is an intercooler?

A specifically designed radiator that cools air before it enters the engine. As a turbo compresses air, the air heats up. Power can be increased if the air entering the engine is cooler, being that a 10deg F drop in charged air temperature is equal to 1% of horse power.

 

Source: http://www.dynamicturbo.com.au/default.asp?p=40