Horsepower versus Torque

My Dad used to explain the difference between horsepower and torque as the following; horsepower is all about how fast you can get to the wall, and torque is how far you can pull it once you get there.  To be honest, at the time, I didn’t really understand what he meant, but it did seem like a cool analogy at the time.

What is more important, Horsepower or Torque?  Well, it has been a topic of a lot of debate over the years, but do you really know what the difference between the two is and is one actually better or more important than the other?

Horsepower is the rating that describes how powerful an engine is.

Torque can be described as how flexible or how much force can be expressed in a given gear.

Torque is a rotational force. Related to an engine, it’s produced by the rotating crankshaft. In North America torque is measured in pounds-feet or lb-ft. Torque is the result of a force acting over a distance and is measured in foot-pounds.

Horsepower, on the other hand is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute. Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you’d have expended one horsepower-minute of energy.

Now, to relate torque to horsepower, the math shows that horsepower and torque are equal to one another at 5,252 rpm. Above that, horsepower is greater than torque.

Which is more important to you should depend on your needs.

A truck with lots of torque can pull a heavy load but post a slow 0 to 60 mph time however a muscle car with lots of horsepower can run though a 0 to 60 mph run in under 5 seconds, but if you add weight to the equation the muscle car will struggle to get moving.

Some say that torque is what gets you moving, and horsepower is what keeps you moving.

But generally, the higher the horsepower, the more powerful the car is and therefore the more horsepower typically means faster overall acceleration and higher maximum speeds.

Higher torque numbers result in better in-gear acceleration (useful for passing or getting the vehicle moving), higher weight limits/towing capacities.

So, I guess it just comes down to what is more important horsepower or torque in a vehicle, it just depends on your demands for the vehicle.

By Jamie Barrie