I’m writing an article for my school’s radio website about engines, and I need some advice on physics.

My article is about torque, and it explains why people need to be critical when reading about a vehicle’s performance figures. My big argument is “Torque is how much force you can apply, not how often you can apply it”

In essence, I say that while power does depend on torque, engines gather power using their torque in different ways. Having a lot of torque doesn’t mean your car is faster. I give as an example a motorcycle and a bus.

A motorcycle (Say, a Ducati Paginale) might have a lot of power but very little torque. The engine is very small but it rotates very quickly. Since power is torque*RPM; we can deduct that the engine produces very little torque, but the high revs the engine can work at means it generates a lot of power. The Panigale V4 generates less than 100 lb-ft of torque, but it generates 214hp, at 13,000RPM.

A Mercedes Benz Citaro makes 282HP but it makes 826 lb-ft of torque, a great discrepancy! But the engine is made to work like this; the Mercedes has a very large engine that can generate a lot of torque, but it spins a lot slower than the ducati because the components need to be beefier because of the extra torque.


The key difference here is what the engines are supposed to be in; the Citaro is a city bus, so it doesn’t need to accelerate quickly or go at a high speed. It does need to displace a lot of mass; so it needs a lot of torque, since this mass is not being displaced at a high speed, it doesn’t need a lot of power.

The ducati on the other hand does need to move and accelerate very quickly, but it has a small mass; torque is not as important in this application.

Obviously, F=M*A but, if my understanding is correct (I could be wrong), this only describes the initial acceleration from a standstill (static?) once the car is in motion, the power sent to the wheels is the number that matters most in both acceleration and speed.


I will be asking a professor about it. But I’d like to avoid making a mistake,