Torque is a feature that is mentioned in all performance car reviews, but it’s arguably one of the most misunderstood areas of car performance. When car manufacturers are discussing their models, they tend to state factors such as power, speed, and torque. The first two are fairly easy to understand, but what is torque and how does it relate to cars?
Quite simply, torque is a measurement of a car engine's rotational force, which is why, like power, torque is always quoted at a particular engine speed, because they are related. Ford states that the 1.0 Fiesta EcoBoost develops 170 Nm or 125 ft-lb @1500 to 4000 rpm. Meanwhile, the Nissan GTR has a figure of 633 Nm or 467 lb-ft @ 3,300 to 5,800 rpm. Plainly the Nissan has a lot more torque than the Ford, and it is regarded as much more than a performance car, but what does this extra torque actually mean?
Torque differs from horsepower as the figure refers to the amount of work an engine can exert, while horsepower defines how quickly that work can be delivered. This is why torque is often referred to in simple terms as the ‘pulling power’ or ‘grunt’ of a car.
A car engine transfers rotational energy from the crankshaft into forward movement. Torque is effectively a measurement of that twisting effect, and obviously is a greater force the more powerful the engine. Hence the Nissan GTR, being more powerful, has a much higher torque figure than the Fiesta.
Torque and performance
Torque is usually measured in Newton metres (Nm), or pound feet (lb-ft) – the latter not to be confused with foot pounds (ft-lb), as one ft-lb refers not to a twisting force, but to the amount of energy required to raise a 1lb weight by a distance of 1ft.
The primary use of torque in an engine is to make the car accelerate, and the number usually quoted is the maximum torque of the internal-combustion engine at the crankshaft component. The measured torque will start to diminish from that point onwards, so the figure is usually not delivered at the amount at the driving wheels.
A greater torque figure also usually means a faster 0-60 mph time as it allows the vehicle to accelerate faster in the initial stages of momentum when the car is beginning to pick up speed.
Torque is always being produced when the engine is running, but a car will feel more responsive when peak torque is developed low down in the rev range, but many people enjoy high-strung engines that need to be revved hard before they develop peak torque, but they can be tiring to drive.
Torque and off-road vehicles
However, torque is not just about high speed. Torque is also a highly important factor when vehicles get heavier and larger in size. A heavier sports utility vehicle (SUV) will need more torque to begin moving or to maintain a speed.
It’s one of the main reasons that you’ll find most heavy and off-road vehicles use torque-dependent, diesel engine vehicles rather than a petrol engine. Off-road vehicles may encounter all manner of obstacles such as long and tall hills, mud, and varying amounts of water. The ground may also be unstable, so the vehicle needs to have lots of torque to enable it to be sure-footed over treacherous ground.
The same argument applies to very large vehicles such as trucks and lorries that may produce huge amounts of torque to be able to pull heavily-laden trailers, but do not have high top speeds.
Benefits of torque
- Easy drive off If a car has a lot of low-end torque, it generally means that you have access to more engine power in lower gears, and you won’t have to down-shift the gears so often when accelerating from low speeds. Subsequently, the drive will feel smoother.
- Carry heavy loads Having a high torque force makes the transportation of heavy loads far easier and more efficient. This also includes driving heavier cars over unstable ground.
- Drive up steep hills It is easier to get up steep inclines and hills in a vehicle that has more torque. Another key aspect of torque is the ability to move from a standing start while on a steep hill.
Torque is a twisting effect created by the engine that works alongside the engines power to help the vehicle move off and maintain its momentum. The more torque an engine has, the easier it is for that vehicle to cope with differences in incline and non-uniform ground such as soft and crumbly surfaces and, for this reason, high torque engines are frequently found in four-wheel drive off-road vehicles.