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Turbo Failure – Overspeeding.

Series 4 of 5

This month we are talking about turbocharger over-speed, another common cause for turbo failure which we see on a regular basis.

With more and more tuning modules and remapping available on the market it’s a lot easier to get more performance out of your vehicle these days.

Just be aware these are not all equal and late model common rail systems are very complex.  Increasing fuel and timing if not done correctly can have a big effect on the life of the turbo.

As a result of poor tuning, failed turbos are becoming a lot more common in our industry.

Previous newsletters have covered topics: Foreign object damage, Blockages to DPF and Oil contamination. Copies of these articles can be found on our website: https://turbocare.co.nz/news-and-events/

What is overspeeding?

Overspeeding is a term used when a turbo is operating well above it’s normal operating limits.

If there are any cracks, leaks or poor seals between the compressor and the engine, the turbo will have to work much harder than it should to deliver the required CFM to the engine.

Causes of overspeeding include:

  • Engine modifications including “chipping” or “large exhausts”
  • Tear in the air hose or the hose becoming completely detached
  • Restrictions in the air-intake filter or pipe work
  • Air leaks between compressor and engine
  • The wastegate or VNT mechanism has been set incorrectly
  • Worn injectors
  • Installing an incorrect turbo
  • Loss of signal to the Electronic Actuator for the wastegate or VNT control
  • High altitude
  • Incorrect movement or restrictions in the VNT mechanism

Preventing turbo failure caused by overspeeding:

  • The turbocharger must always be left in original state
  • The turbocharger may only be installed in the specified vehicles
  • Check there are no restrictions or leaks in the air intake pipe work
  • Ensure the wastegate or VNT linkage is operating freely and is properly calibrated
  • Check the electronic sensors and Ecu are operating correctly
  • Avoid remaps chipping or over-fuelling