Horsepower, Turbo, Torque, what does it all mean? Why does it matter?
Horsepower is the most commonly used term to illustrate the amount of power an engine can generate. It measures how much sustained work an engine can do. One unit of horsepower is specifically measured as 33,000 foot-pounds per minute. This equates to 746 watts, 2,545 BTU’s, or 2,684,975 joules of energy.
However, using horsepower can seem unusual to people who are not familiar with the history of engines. It was coined in the mid-late 1700s by James Watt, an engineer who worked on steam engines. He wanted a way to articulate the power generated by horses, so he could explain how much more power an engine had. It became a widely-used way of describing engines to those who were unfamiliar with how they operate, as a way of comparing apples to oranges. Now, anything with an engine will describe its horsepower, whether it’s a lawnmower or a car/truck.
You may have noticed that your vehicle has extra numbers and or letters in the emblems on your trunk, tailgate, and/or your owner’s manual description of the engine. If it includes the letter “T” (like 2.0T), your engine may be turbocharged. Many engines have what is called a turbocharger. It is used to boost the power of an engine. For example, a four-cylinder engine with turbo can produce as much power as a larger, six-cylinder engine. However, as a smaller engine, the four-cylinder uses less fuel when driven normally. This means you get the benefit of better fuel economy, but have the added power when you need it.
Torque is a little different from Horsepower, but is also a measurement of engine power. However, torque measures an engine’s pulling power from a stopped position. Trucks need a lot of torque in order to move heavy loads. The hardest part of towing for an engine is getting the load moving, which is where high torque is important. Once the vehicle is moving, other factors like horsepower and speed are important.
Horsepower vs. Torque
The two concepts are closely related, because horsepower is a function of torque and engine speed. You can calculate horsepower by multiplying torque by engine speed in RPM divided by 5,252 (horsepower=torque x [RPM/5,252]). Also, keep in mind whenever you hear about horsepower and torque that these are peak engine numbers. Only an engine with a turbocharger is likely to be able to sustain peak torque for any length of time.
However, thinking about the Horsepower, Turbo, or Torque will not give you the full picture, because these concepts work together to create the overall driving experience. A truck with high horsepower, but low torque will feel like it does not accelerate well from a stop, but will feel stronger at higher speeds. A high-torque, low horsepower engine will accelerate more smoothly from a stop, but will struggle as the engine speeds up (until your transmission shift gears). How much a car/truck weighs can also have an impact on acceleration. So even if the engine is very large, a heavy vehicle will significantly affect how it feels when you drive it. Also, high torque engines can cause issues with wheels slipping in low traction situations, like rain and snow. Ultimately, finding the vehicle that feels comfortable while driving and can do the work you need it to should be your primary focus when selecting a vehicle.