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Engine Temperatures

EDM unit

Cylinder Head Temperature (CHT)​

The cylinder head temperature (CHT) is the temperature of the cylinder head, which measures heat expended during the power stroke.

High CHT can cause detonation, pre-ignition, and engine damage. High temperatures indicate that the engine is under excessive load.

For most high-performance engines, the maximum CHT is around 400°F. Pilots should take action to reduce CHT if it exceeds this value.

Things that can affect CHT include:

  • Power setting
  • Mixture
  • Cooling airflow over the engine
  • Cowl flags
  • Timing, spark plug failures, and magneto problems

Exhaust Gas Temperature (EGT)​

The exhaust gas temperature (EGT) is the temperature of the exhaust gases as they leave the cylinder, which measures the heat expended during the exhaust stroke.

This is an indication of the energy being wasted in the exhaust gases. High EGTs do not pose a threat to the engine, but they do indicate that the engine is not running efficiently.

Leaning operations​

Pilots can lean the mixture to reduce EGTs.

As a general rule, the best power mixture is around:

  • 100°F rich of peak
  • 20°F to 50°F lean of peak

Turbine Inlet Temperature (TIT)​

On turbocharged engines, the turbine inlet temperatures measures the temperature of the air before it enters the turbocharger turbine.