Importance of downshifting: Reducing engine wear and fuel consumption

A practical driving technique reduces fuel consumption and decreases vehicle wear. However, even experienced drivers may fall into old habits that lead to mistakes. One is improper clutch engagement, which means not downshifting before accelerating.

A typical scenario is an empty road with good car performance where the driver wants to overtake a slower vehicle. In such a situation, many of them do not downshift, assuming that the available space and time for the manoeuvre are sufficient, and the car will accelerate by flooring the accelerator. However, this is a mistaken approach that can negatively affect engine performance.

Drivers also believe accelerating at lower revolutions per minute (RPM) is better because it generates less noise. Meanwhile, excessive load at low RPMs harms the engine. In this range, the engine operates less efficiently, meaning that a more significant portion of the energy from the fuel is converted into heat instead of vehicle acceleration. This leads to higher fuel consumption and overheating of internal engine components.

Excessive overheating, in turn, leads to uneven combustion of the fuel-air mixture and ignition problems. As a result, internal forces in the cylinder are distributed unevenly, accelerating engine wear. This situation is particularly unfavourable for modern turbocharged engines, where the risk of pre-ignition is significantly higher.

Studies conducted by Japanese companies Toyota and Denso, a spark plug manufacturer, confirm these issues. The research results indicate that improper clutch engagement leads to glowing fuel and oil residues in the engine, which increases the likelihood of pre-ignition and accelerated wear of pistons and spark plugs.

During driving courses, the necessity of downshifting before accelerating is often emphasised. The overtaking manoeuvre is one of the most dangerous on the road and requires the quickest and safest completion possible. Therefore, downshifting maximises the car's acceleration potential, which is crucial for safely overtaking another vehicle.