Horsepower and torque are two of the most contested performance terms in the auto realm. Today, we’re going to take a look at how they fair on the racetrack. Which factor is more important in the performance world, horsepower or torque?
Keep reading and we’ll get you up to speed!
Horsepower vs. Torque: Two Sides of the Same Coin
Horsepower and torque are all about power and where it takes place.
Torque is a raw measurement that accounts for rotational force that occurs within the engine, specifically at the crankshaft.
Horsepower is a man-made calculation that measures the amount of power that occurs on a larger scale at the wheels and under the hood. Horsepower encompasses weight, distance, and time (i.e., what’s being moved, how far it’s going, and how long it takes to do so).
Check out the following equation that helps put the relation between torque and horsepower into perspective:
Horsepower = (Torque x RPMs) / 5,252
What do RPMs (or engine revolutions per minute) have to do with racing? Higher revolutions per minute equate to more fuel burnt in the same amount of time and more power produced. Because of this, most consider higher RPMs racing RPMs.
Running at lower RPMs equates to higher torque and thus lower horsepower, while making higher RPM power outputs less torque and higher top horsepower. In a straight line race, higher RPMs take precedence.
NASCAR racecars operate at very high RPMs. That’s not to say these cars lack torque—torque, after all, is responsible for horsepower, but it does mean that the ratio composition points to smaller torque numbers and higher RPMs and thus higher horsepower.
Torque Gets You Off the Line, Horsepower Gets You Ahead
In an evenly matched race, with Racecar A touting more torque at lower RPMs and Racecar B possessing more high RPM horsepower, who would win? Racecar A will be quicker to accelerate off the line and might look as if it has the lead at the beginning. But once Racecar A shifts into second gear, it will lose its acceleratory bump. By the time Racecar A shifts into third gear, high-horsepower Racecar B will be the new leader.
A hefty diesel dump truck creates huge amounts of low-end torque. You can set it side by side with an exotic sports racer designed to channel high-range RPMs and likely know which model will move faster. But so many other factors come into comparing the horsepower and torque between the two vehicles, the overall vehicle weight and the gearing setup being two major influential elements.
While choosing horsepower over torque and vice versa may feel like a case of the chicken and the egg, one thing we can be sure of is that they’re both vital to performance racing.
Making internal modifications and using exciting diagnostic equipment to test engines, ATC’s Hi-Performance auto students get to know the play between horsepower and torque better than most people ever will.
Revved up to learn more? Check out ATC’s student resources page for more compelling automotive topics!