Ask the Mechanic: Do high rpms always mean higher fuel consumption?

What you need to know:

  • Hello Paul, you have discussed the relationship between rpm and kph. Could you also confirm the myth that anytime your rpm is beyond 2000 your fuel consumption increases exponentially? David.

It is generally true that an increase in an engine’s revolutions per minute (rpm) beyond 2,000 usually results in an increase in fuel consumption. Therefore, keeping the rpm below 2,000 can result in reduced fuel consumption since faster engine rpms increase load on the engine and demand for fuel. Faster engine rpms may not always cause exponential increase in fuel consumption.

In cases where a car has efficient technology such as Variable valve timing (VVTi), Continously Variable transmission (CVT) or Hybrid Electric vehicle fuel consumption may still be moderate at 2,000 rpms.

Driving conditions, such as driving downhill, even at 2,000 rpm, may not necessarily increase fuel consumption. This is because momentum may help to carry the load.