Mazda BT50 Turbocharger Failure Analysis - Overspeeding Damages Turbos

Mazda BT50 Turbocharger Failure Analysis - Overspeeding Damages Turbos

Wei Wei |

Recently, we have supplied and replaced a turbocharger for Mazda BT-50 2.2L. Before fitting a new CCT turbo into the car, we conduct a thorough diagnostic check of the engine & turbo system. When the original turbo was pulled apart we found the the failure of the turbo was caused by over-speeding. Below are the photos of the damaged original Mazda BT50 turbo that caused by overspeeding.

turboc overspeedingturbo overspeeding

Overspeeding makes the turbo beyond its safe operation limits, which causes the failure of turbo by damaging the compressor wheel or turbine and its bearings. Even worse, the engine can be over-boosted if the turbo continues to overspeed.

Now you may ask what is the reason that causes turbo over-speeding? 

  • any restriction in the air intake system or a split or broken air house will make incorrect amounts of air into the turbo, causing the turbo wheels over speeding.
  • A "chhipped" or "overfulled" engine that is not standard.
  • Worn injectors.
  • loss of signal to the electronic actuator for the wastage or VNT control .
  • Incorrect turbo fitted.

How can you prevent turbo over-speeding?

  • Make sure there are no restrictions or leaks in the air intake pipe work.
  • make sure the wastage or VNT is operating freely.
  • Make sure the electronic sensors and ECU works correctly.


Here at Demon Pro Parts, we supply and fit turbochargers. With experience and knowledge of turbos, we diagnose the problems and then repair them accordingly to prevent you from having to buy a new turbocharger just 6 months later.

Have problems with your turbocharger?

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