Understanding Torque and Horsepower
Torque and horsepower are two terms used to describe the power of an engine, especially when talking about trucks or the insane engines on the Dodge Charger and Challenger lineup. However, just because those are everyday terms, doesn’t mean consumers really know what those terms mean. Kind of like the saying, “If you can’t bedazzle with brilliance, then befuddle with bull.” So, we thought it’s time for a little education.
What is Torque?
The Dodge Challenger SRT Hellcat has 650 lb-ft of torque, but what does that mean? The most basic definition of torque is the rotational force around an axis. Basically, the force applied when a wheel rotates around the axle. It’s measured like so: units of force X distance from axis, i.e. 10 pounds of force and a wrench one foot long: 10 lbs X 1 foot = 10 lb-ft of torque. Look familiar? So when an engine generates 650 lb-ft of torque, what it’s saying is that it needs 650 pounds of force on a 1-foot lever to stop its motion.
On vehicles like the Dodge Challenger or the new Ram trucks coming out, torque is important. Without enough torque, those wheels won’t spin as fast, and not enough work can be completed. Wait, what does work have to do with this? Well, trucks are typically used for towing or hauling heavy loads right? Well, just because those wheels are turning doesn’t mean any work is getting done.
According to scientists, work is done when a force is applied to an object and successfully moves that object. Now, force can be applied in a push or pull motion, such as in the case of towing. It’s said that 1 lb-ft of torque can equate to 6.28 ft-lb of work. So when a new Ram 2500 puts out 400 lb-ft of torque, it can produce 2,512 lb-ft of work during a single rotation of one wheel. With that in mind, with the right equipment, it’s no wonder the Ram 2500 has a standard towing capacity of 11,250 pounds.
What is Horsepower?
Alright so we understand torque in a sense, but what about horsepower? Well, this one is a little easier to explain. Power is expressed as the rate of speed work is performed. The more power there is, the faster work is done.
Let’s throw in an example to make some sense of it. Say we need to move a 100 pound wheel down the street. There’s us, and a “World’s Strongest Man” competitor. We may be able to roll the wheel down the street in a minute, whereas the big guy can do it in 20 seconds. He completed this three times faster than us, and therefore he’s also three times more powerful.
Now, that’s talking about manpower. For horsepower, it’s defined 33,000 lb-ft per minute. So for an example, if you were to lift 33,000 pounds one foot high over a period of one minute, you will have expended one horsepower-minute of energy.
That’s really the easiest way to put this without getting a bunch of math involved that is more confusing than it’s worth. So to sum it up, if torque is the force applied to perform work, then horsepower is how quickly that force is applied over time. Which is why car engine specs always highlight horsepower and torque.
Think about it – a Dodge Challenger Hellcat can generate 707-horsepower and 650 lb-ft of torque. Together, it can move the Challenger, a vehicle weighing over 4,000 pounds, a quarter- mile in 11.8 seconds. Now that’s fast and powerful!