Wednesday, May 02, 2007

FAQ About Turbochargers


What type of oil and how often should it be changed ?
Turbos must have good quality oil. Use either a semi or fully-synthetic engine oil. Turbo Technics recommends Shell Helix Plus, Shell Helix Ultra or Mobile 1. Change oil at intervals recommended by the vehicle manufacturer.

How long does a turbo last ?
On average, about 75,000 miles with regular engine servicing and good quality engine oil.

What is a dump valve ?
A valve which relieves back-pressure between the compressor outlet and engine as the throttle is closed. Only sometimes required on engines producing in excess of 14psi boost pressure.

Can I fit a turbo from another car ?
No, virtually all turbocharger are different inside, even if they appear similar on the outside. The turbo model e.g. Garrett T3, is only the model, not the specification.

What is a hybrid turbo ?
A hybrid turbocharger is a special, which combines quick boost response, required at low engine rpm, with the extra air-flow capacity needed for more power at higher revs.

Can I increase the boost pressure on my engine ?
Only if the engine has been modified to accept these changes without forsaking reliability.

Should I leave my engine ticking over before it is turned off ?
Not for normal every day driving, but still worthwhile if the engine has been under load or raced before being turned off. e.g. Towing a caravan or after climbing a long incline.

Why is it important to balance a turbocharger ?
Without highly accurate balancing, vibration will create a whining noise, reduce turbo bearing life and reduce turbo efficiency.

What should the boost pressure be set too ?
This will vary for every different car manufacturer, seek their advice before adjusting.

How many psi in one bar ?
14.7 psi = 1 bar.

Can I fit a bleed valve ?
A bleed valve reduces the signal pressure to the actuator wastegate. It has the effect of increasing the boost pressure. Engine damage will result unless the engine is previously modified to accept this change.

Are all actuators the same ?
No, each has a different opening pressure and rate.

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.

Should a turbo be serviced ?
No specific turbo servicing is required, but regular quality engine servicing is needed to reduce the chance of turbocharger problems.

What is a water-cooled turbo ?
The central part of the turbo, housing the bearings, is surrounded by a water jacket through which the engine's water coolant is passed. This water continues to circulate after the engine is turned off, cooling the turbo, and preventing heat soak.

What is a 360ยบ thrust bearing ?
This is an uprated turbo bearing. It has a greater bearing contact face to withstand the high loads which would otherwise destroy a standard bearing very quickly. Mainly used on competition and hybrid turbos.

Why is my car smoking at the traffic lights ?
One of the typical early symptoms of a turbocharger problem is a hazy blue smoke being emitted from the exhaust tailpipe whilst the engine is ticking over.

How noisy should a turbo be ?
Only an unbalanced, worn out or damaged turbo will produce any significant turbo noise.

What is an intercooler ?
A special type of radiator which 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.

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