Horsepower Vs. Torque: A Simple Explanation
Last week’s article shed some light on the difference between horsepower and torque. We compared two pretty similar vehicles with similar performance numbers that similar people would buy. The Toyota Camry and Mazda 6 are both midsize cars that are reasonably priced. For the sake of argumentation, we will assume that somebody looking to purchase a midsize car would explore the option of buying one of those two cars.
This week, we’re going to take two completely different cars to explain the difference between horsepower and torque a little more in depth. First we’re going to consider the 2018 Ford F-250 Powerstroke Turbodiesel pickup truck. I know it’s not even a car. That’s OK… After that, we’re going to make a complete turn and look at the 2004 Honda S2000. While these two vehicles are in no way related or even similar to each other, they are perfect for giving us an example of how horsepower and torque are different. Let’s look at the Ford first.
2018 Ford F-250 Powerstroke Turbodiesel
It’s quite obvious that this truck is built for work. Most trucks are built with a significant focus on hauling and towing capacity over most other vehicles. SUVs and cars can haul a trailer as well, but not to the extent of most pickups. The F-250 is a standout in the work category. The truck is available with two engines. The first is a 6.2 liter V-8 and the second is a Powerstroke Turbodiesel engine. We’re going to focus on the second one.
We all know that diesel engines are usually meant for those vehicles that need more hauling capability or for cars whose main goal is efficiency. The “power” part of that is actually a bit of a misnomer. It’s actually the torque that does the heavy lifting, and it allows all the actual power of the diesel engine to be put to use. The F-250’s turbodiesel engine produces 440 horsepower. That’s quite a bit, but the Grand Sport Corvette produces 450 horsepower. Why can’t the Corvette tow as much as a diesel pickup? It’s because the F-250 produces 925 lbs./ft. of torque… on top of the fact that the Corvette is a sports car.
All of that torque allows the F-250 to put all its available power down at just about any RPM and gives the truck the capability to tow up to 15,000 pounds. The Corvette certainly is fast, but it wouldn’t be able to tow that much, nor is it supposed to. The truck was designed to do that. The turbo mated to the engine is part of the reason it can produce that much torque. As the turbo spins, more compressed air is forced in into the combustion chamber allowing a higher compression ratio and therefore a higher amount of torque. This is a common consequence of a turbo engine, even if the engine isn’t diesel-powered.
2004 Honda S2000
You may not remember the S2000, but I guarantee you that every enthusiast does. Honda doesn’t make the S2000 anymore, but it was truly a great car. For those who don’t remember, it was Honda’s convertible sports car made from 1999-2009. Think of a Subaru BRZ as a convertible with a little more power. The S2000 was and continues to be one of the best handling and most entertaining cars ever. Its 4-cylinder engine produced a healthy 237 horsepower, but only produced a measly 162 lbs./ft. of torque. That’s 763 less than the F-250!
Obviously, a two seat convertible sports car isn’t meant to tow campers and haul logs around, but that torque number is still pretty low. Therein lies the magic of the car. I mentioned that the S2000 is quite possibly one of the most fun cars to drive… ever. The torque, or the lack thereof, is the exact reason the car was so much fun to drive.
Peak torque didn’t hit until 6800 RPM, much higher than most normal engine redlines today. That meant that the driver of the car had to floor the accelerator to get it to “go fast”. It also meant that driving around town, while still fun, may have been a bit lacking in the get-up-and-go category. The true expression of the S2000 was both seen and heard on the winding backroads when the operator could let the engine rev as high as it would go.
Torque is a really good measure of how usable a car is. Even if a car doesn’t have a lot, if the peak torque of a car is at a usable limit in the rev range – say 2500 or 3000 RPM – the car is going to feel more powerful and usable than it may actually be. For the F-250, the torque is usable almost all the time just because it has so much. The Honda would never reach all the torque available to it under normal driving conditions, and it felt slower than it actually was.
What does that all mean for you? It may not mean anything at all. At least now you know the difference between horsepower and torque. Though it may not affect your decision when it’s time to go buy a new car, you can be better informed about what you are getting as you glance down the window sticker or research cars on the internet.
–SWF
