To say that electric cars are amazingly fast is an understatement. Models like the Tesla Model S Plaid can easily accelerate from 0 to 60 in less than two seconds under the right conditions. This puts them in the league with some of the most expensive and powerful supercars. However, the driving force behind the astonishingly fast acceleration of electric cars is instantaneous torque, something that petrol-fueled supercars don’t have.
But what is instantaneous torque, how does it work, and why electric cars have it while their fuel-powered counterparts don’t. Answering these questions can be difficult without explaining what torque is, how it is measured, and why it is so important in cars.
What is torque
A simple explanation for torque is that it is a torsional force. You can see examples of torque in everyday life, such as when opening a door or tightening screws. In these examples, you apply a bending force to either the door handle or the bolt with a wrench.
Torque is measured in pounds-foot (lb-ft), and in an engine, the torsional force or torque is needed to rotate the crankshaft continuously. Torque is then transmitted to the vehicle’s wheels, allowing it to handle heavy-duty chores such as going uphill, taking off-road, and pulling trailers.
It is even necessary to push the car forward from a standstill. As such, it’s no surprise that the Rimac Nevera, an EV with 1,741 lb-ft of torque according to MotorTrend, has one of the fastest acceleration speeds on the market. Rimac claims that the electric supercar can go from 0 to 60 in 1.85 seconds.
How is peak torque achieved in petrol cars versus electric cars with instant torque
With petrol cars, maximum torsional power or peak torque can only be achieved at some engine rpm, which varies from model to model. For example, the 2022 Dodge Charger SRT Hellcat Redeye Widebody’s peak torque is 797 lb-ft at 6300 rpm.
For context, engine revolutions per minute (RPM) measures how fast the engine is running at any given time.
It should be noted that the torque either increases or decreases if the car is not at the specified engine speed. Also, if your car starts at low rpm, it takes some time to reach the required engine speed for maximum torque.
Conversely, the maximum torque in electric cars is achieved the moment you hit the accelerator pedal, and thus the instant torque. According to Car Throttle, this is mainly because there is too little rear motive force (EMF) in the electric motor that powers the car’s wheels.
Return EMF is an opposite electromotive force that increases in the electric motor as it rotates faster. Unfortunately, the rear EMF also reduces the working effort of the vehicle, which in turn lowers the power that reaches the vehicle’s wheels. The working voltage is usually the result of the supply voltage minus the electromotive force.
To put this into perspective, if you power a 120V motor and the back EMF is 90V, you will only have a working voltage of 30V. Conversely, if the motor is not rotating, there will be no return EMF which means that the entire 120 volts of power can be used to create the torque.
Since electric motors hardly spin before they start driving, there is little or no EMF going back, thus, electric vehicles always seem faster off the line. However, the motors will spin faster just by driving; Therefore, return EMF is bound to accumulate.
This creates problems on the higher end, so electric cars have a hard time getting past a certain point, like around 150 mph.
Other reasons why electric cars are so fast off the line
There are also other reasons why electric cars like the Lucid Air Dream Edition might beat tough companies like the McLaren Senna to the 1/4 mile mark in a drag race. The first is the placement of the motors, as most electric vehicle manufacturers place them on the front and rear wheels. The result is extra traction, which means the wheel is spinning as little or no spin as possible just by depressing the accelerator pedal.
In addition, electric cars are distinguished by the presence of only one gear compared to the multi-speed gearbox of petrol cars. Thus, you don’t have to wait for a multi-speed gearbox to go down before you can deliver the engine’s power to the wheels. This makes the cars more responsive to the throttle.
Related: How Much Torque Is Enough in a Truck?