It sounds like this“Electric cars feel so quick because their motors are far more powerful than petrol engines.”
Thinking electric cars feel quick because they have much more horsepower
Why it feels right
Electric cars are famous for being quick, and the numbers on their spec sheets are often big. Fast electric cars have 500 horsepower or more, and it is easy to conclude that an electric motor must simply be a stronger kind of engine. 'Instant power' is the phrase everyone uses, and it blurs torque and power together.
Why it’s wrong
Peak power can be about the same. What differs is where the push comes from: an electric motor makes close to its full torque from a standstill, so the car has its full push the instant you press the pedal, while a petrol engine has to rev up first.
A worked example
A petrol engine makes almost nothing at idle. It builds torque as it revs, and its power peaks at a high rpm. A gearbox must also pick the right ratio. So when you press the pedal, the engine has to rev up, and the box has to change, before you get full push.
A typical electric road motor makes close to its full torque from zero rpm up to a speed of about 4,000 rpm (its base speed), and beyond that it holds roughly constant power, so torque falls away. Take one rated at 167 kW: at 4,000 rpm (419 rad/s), the torque is 167,000 / 419 = 400 N m, and it's about 400 N m the moment you press the pedal at a standstill.
So a 150 kW electric hatchback and a 150 kW petrol hatchback have the same peak power. But the electric one has its full push straight away. A car that has its maximum push at every speed from a standstill pulls away much quicker than one that has to rev through its range first. Also, one forward gear is enough, so there are no delays from gear changes.
How to catch yourself
- You say electric cars 'have more power' because they're quick off the line.
- You compare an electric car and a petrol car by kW alone.
- You use 'instant power' to mean more power rather than earlier push.
What to hold instead
An electric motor makes close to full torque from zero speed, so the car has its full push the instant you press the pedal. A petrol engine has to rev up and shift gears to get there. Cars with the same peak power can feel very different because of how and when that power arrives.
Where you’ll meet it
- Wondering why a modest electric hatchback beats a sports car off the line.
- Understanding why electric cars need only one gear.
- Reading why electric trains can start heavy loads.
Questions people ask
- Why are electric cars so quick off the line?
- Because an electric motor produces nearly its maximum torque from standstill, so the full push is available immediately. A petrol engine makes little torque at low revs and needs gears to multiply it. Peak power can be similar; what differs is when the push arrives.
- Why do electric cars only need one gear?
- A motor works well over a very wide speed range, up to about 15,000 rpm, and torque is high from zero, so a single fixed reduction gear is enough. Petrol engines work well only in a narrow range, so they need several gears.