Brake Specific Fuel Consumption

"Brake specific fuel consumption (BSFC) is a measure of the fuel efficiency of any prime mover that burns fuel and produces rotational, or shaft, power. It is typically used for comparing the efficiency of internal combustion engines with a shaft output.

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Commonly BSFC is expressed in units of grams per kilowatt-hour (g/(kW·h))."- Wikipedia

Hybrid Assistant shows BSFC in the Engine Power Meter using a color scale reflecting efficiency:

Cyan - Best efficiency range (220 g/kWh)

Yellow - High efficiency range (230 g/kWh)

Orange - Medium efficiency range (240 g/kWh)

Red - Low efficiency range (> 240 g/kWh)

Actual thresholds vary with engine type, according to official Toyota documents

Example chart from a Toyota Yaris