In the days before cars, humans used horses and wagons to move people and cargo from place to place. There were no cylinders to compare power, just the number of horses hitched to a wagon. Once the automobile was invented, the carmakers touted the speed of these new-fangled contraptions in comparison to the power of horses. At some point in this early history, someone figured out that it would take the power of one horse to move 550 pounds one foot in one second or 33,000 pounds one foot in one minute. With this, the modern metric of horsepower was born.

Today, horsepower is measured with a dynamometer… well, actually, it’s the torque that is measured by the dynamometer, and the horsepower is the product determined from that. Torque is measured at various engine speeds or revolutions per minute (RPMs). Here is the actual formula:

(Torque × RPM) ÷ 5,252 = Horsepower
 

Let’s break it down: torque is the rotation of the crankshaft (the part of an engine that moves the rods and pistons upward, thus creating combustion). Horsepower is the rate at which torque is applied for the output. Torque is measured by determining the amount of force multiplied by the length of the lever through which it acts. For example, if 10 pounds of force is applied to a bolt head with a wrench that is one foot long, 10 pound-feet of torque is generated.

Having said all that, which is more important: horsepower or torque? The answer is going to vary depending on the type of car you want to purchase. A lightweight sports car may have high horsepower and lower torque, which equates to a small amount of force applied at a fast rate. On the other hand, most trucks have high torque and lower horsepower. They need power but not speed; that starts to really make sense if you want to tow a boat or camper. Torque helps you get going.

When considering what kind of vehicle you need, think about whether you want fast-moving speed or load-hauling strength to meet your day-to-day needs, and the answer will reveal itself. Then, there's always this old chestnut:

Understeer is when you hit the wall with the front of the car.
Oversteer is when you hit the wall with the back of the car.
Horsepower is how fast you hit the wall.
Torque is how far you take the wall after you hit it.

- Old racer’s creed

We hope this detailed explanation was helpful, but we know nothing teaches quite like a hands-on experience. If you would like a live demonstration of the difference between horsepower and torque, the sales team here at Germain Honda of Dublin loves educating our clients. Contact us online to schedule a test drive!