Frequently Asked Questions
How long does a turbo last ?
This will depend greatly on the use to which the vehicle is subjected. In general use with frequent longer journeys, TT would expect at least 100,000 miles with regular engine servicing and good quality engine oil, although this could vary widely.
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. Where the vehicle manufacturer does not specify, Turbo Technics recommends Shell Helix Plus, Shell Helix Ultra or Mobil 1. Oil change intervals should be as recommended by the vehicle manufacturer, unless experience dictates more frequent changes.
What is a variable-vane turbo ?
A turbo with movable vanes surrounding the turbine wheel, which can be moved to alter the speed of the gases approaching the wheel. This can give more boost at low engine speed, overcoming turbo lag. Click here for more details.
What is a dump valve ?
Normally used on a petrol engine, a valve which relieves back-pressure between the compressor outlet and engine as the throttle is closed. This reduces noise and ‘chatter’ when driving.
Can I fit a turbo from another car ?
No – virtually all turbochargers are different inside, even if they appear similar on the outside. The turbo model number, e.g. Garrett GT15, is only the model, not the specification.
What is a hybrid turbo ?
A hybrid turbocharger is a special build which normally allows extra air-flow capacity that is 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. This typically requires an ECU re-map but other mechanical changes may also be needed.
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 run at high speed immediately before being turned off. e.g. Towing a caravan, climbing a long incline, or high-speed cruising.
Why is it important to balance a turbocharger ?
Without highly accurate balancing, vibration will cause a whining noise, and reduce turbo bearing life.
What should the boost pressure be set too ?
This will vary for every different vehicle application. Check manufacturer’s data before adjusting.
How many psi in one bar ?
14.5 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 may result unless the engine is also 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 engine oil and filter changes are needed using good quality materials.
What is a water-cooled turbo ?
On most turbos (not all) the central part housing the bearings is surrounded by a water jacket through which the engine coolant is passed. This continues to circulate after the engine is turned off, cooling the turbo, and preventing heat soak.
What is a 360º 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.