Are you wondering what the difference is between horsepower and torque? Make sure you keep reading below to learn everything you need to know.
Any true gearhead has engaged in the torque vs. horsepower debate at least once. It’s hard to miss any commercial vehicle advertisement without the words torque and horsepower in them. One can’t help but wonder what these two terms mean and if they’re any different.
The torque vs. horsepower debate is one that has raged on for ages. In an attempt to quash this debate, we’ll be expounding on both terms and highlighting their key difference. Hopefully, by the end of the piece, we’ll have conclusively established, which is more important.
A certain Uncle Joe once said that torque and horsepower are the same thing, only different. This could be an accurate oversimplification, but the only way you can know for sure is to read on and find out.
What Is Torque?
Before we dive into what torque is, let’s first examine what happens when you turn on the ignition. When you start the engine, a spark ignites the mixture of air and fuel in the engine’s combustion chamber. This causes a series of multiple mini-explosions that move the drive axles, crankshaft, and transmission.
That is a conversion of potential energy in oil into kinetic energy that moves the crankshafts and axles, then ultimately moves the car. With that in mind, let’s now look at a few definitions.
Energy – A simple definition of energy is the capacity to do work. As a human, you need energy to do work, and so does every other living thing and machine out there.
Work– work is the product of force, and the distance the force moves an object. Work is measured in joules or as per the international system of measurement or SI unit
Torque– Torque is a rotating force. Unlike linear forces, torque moves either clockwise or anti-clockwise.
By that definition, torque is the rotating force the crankshaft in the engine produces. The more torque produced in the engine, the more work the engine does. The SI unit for torque is similar to that for work but a little different. That’s because torque is a vector quantity and acts in a particular direction while work is a scalar quantity.
Aside from the usual torque that the crankshaft produces, we also have static torque. Static torque doesn’t produce angular acceleration. It’s the type of rotating force that you’d use to tighten a loose nut.
That’s pretty much all there is to torque. It’s the rotating force the crankshaft produces that causes the vehicle to move. With that out of the way, let’s move on to horsepower.
What Is Horsepower?
Horsepower is clearly a combination of two words, “horse” and “power.” Horsepowers has nothing to do with a horse or any animal for matter. The focus word is power, so what is power.
Power is the speed of doing work, as simple as that. Horsepower is only a measurement or quantifier of power. One horsepower is the amount of power that can lift 33,000 pounds an entire feet in just sixty seconds.
Just to be clear, the SI unit of power is Watt or KiloWatt and not horsepower. Remember that torque is a form of energy, and energy is the capacity to do work. Power is how much work can be completed in a given time; then there’s an obvious correlation between torque and power.
In fact, mathematically, horsepower is the product of torque and revolutions per minute divided by 5252. Revolutions per minute, in this case, is speed of engine spins and 5252 is a constant.
With that in mind, think of how car manufacturers increase a vehicle’s horsepower. Well, that’s simple, from the equation above, the manufacturer only has to increase the car’s torque and its revolutions per minute.
How to Measure Horsepower
If you want to measure the horsepower of any machine, you’ll need something called a dynamometer. A dynamometer works by putting a load on top of the engine. It then measures the twisting force the engine pushes the load with.
You can think of the load as a brake that prevents a wheel from spinning. Although the dynamometer measures horsepower, all it does is actually measure the crankshaft’s torque. You get RPM value by measuring torque at various engine speeds.
You then input both values into the expression mentioned above, and you’ll get the horsepower. You can break horsepower into two different types, net, and gross horsepower.
Gross horsepower removes most engine loads during measurement. Net horsepower is the horsepower of a brand-new vehicle with no mileage. Net horsepower is what car manufacturers use for their advertising.
How Are Torque and Horsepower Related?
The simple mathematical expression shows the relation between torque and horsepower. The relationship between the two becomes much more apparent in the automotive industry. These numbers are tossed around by car manufacturer companies to show consumers what the vehicles can do.
Torquecars, for instance, has some great examples of how crucial horsepower and torque are in car tuning. That’s because a car’s driving and hauling ability are determined by its horsepower and torque, which depends on the engine design.
If torque denotes work, then horsepower denotes how fast the car can complete work. The low gear in a pickup truck can relay a specific amount of torque for carrying heavy loads. If you put the same gear on a saloon car, it can’t move the heavy load because it has lower horsepower.
Torque is what it actually converts into power for real-world applications but not the same applications. For instance, the torque from a race car accelerates the car forward. The torque from a tractor, on the other hand, is for towing and lifting heavy loads.
Both are Equally Important
When it all boils down, both torque and horsepower are equally important in a car. Since you can’t have one without the other, you should consider both. What should be pivotal, however, is the purpose of the vehicle, then horsepower can become a primary consideration.
Cars are great and all, but have you checked out our other article. For more informative and enticing reads, be sure to check out the other pieces on the site.
Author: Darcy Reed