Horsepower vs. Torque: Which is More Important? (And Why)
People judge cars solely by the numbers. However, the question is: Which of these numbers is really important? There’s brake horsepower (BHP), torque, gas mileage in the city and on the highway, its range (for electric cars), cargo capacity, curb weight, rear passenger leg room…the list goes on.
In today’s blog, we’re looking at 2 of these metrics, BHP and torque, and asking the core question of which is more important and why. The OEMs are the dealers that sell cars and these numbers are often cited by car enthusiasts who are eager to find out how powerful their vehicle is. Below we’ll look at which one gives you the better picture.
Horsepower and Torque
First of all, let’s be clear about the two factors we’re discussing and exactly what they mean.
Horsepower or BHP
The engine's pure, unrestricted horsepower is the power that it produces without considering any loss of power such as noise or heat. BHP generally determines the maximum speed of any vehicle. That is why many people tend to consider the most powerful cars as being the ones with the highest horsepower.
If you’re wondering about the difference between BHP and HP, the latter is the same unit of power, but this time taking into account the losses caused by things like heat and noise. You can further break down horsepower by dividing it into wheel HP or crank HP. The first refers power at the wheel, and includes power loss due to the transfer of power from engine to wheels. Crank HP is the power that an engine generates without transmission loss.
Simply put, torque can be described as rotational force. It is determined by multiplying force by length. Because many parts of the vehicle depend on torque, it is crucial that they have the same rotational force. For example, pistons are pushed and flywheel rotates.
Therefore, the figure of torque that your car has — typically measured in pound-feet (lb-ft) and in some countries using Newton-meters (Nm) — dictates how much “turning force” it has. It tells how well or normal the car would run when it was laden with baggage or traveling up steep hills.
A car that can produce more torque per pound-feet and at lower RPMs will be more adept at acceleration, maintaining cruising speed when heavy laden and dragging itself up hills with any payload.
Real Life Applications
How do BHP and torque figures get applied to actual-world vehicles? Let’s say you have two cars, one boasting 240hp but only 144lb-ft of torque, and another with 180hp but 175lb-ft of torque. These numbers can be used to tell us a lot about any make and model, regardless of the vehicle they're from.
Car 1: 240 hp, 144 lb-ft Torque
This car is built to perform. It’s likely a sports car that’s loaded with “racetrack DNA,” built for a high top speed, pleasing acceleration and dynamic performance all round. Its torque, while not very low, isn’t commensurate with its raw power and speed in horsepower terms.
Car 2: 175lb-ft Torque and 180hp
Perhaps this car was designed for utility. Because of its massive torque, it's likely to be capable carrying more payloads and pulling smaller trailers. It can also handle steep terrain. This could be an SUV.
It may appear to be a simplified explanation to others, but performance and utility are the key determining factors in application. BHP is a measure of a vehicle's performance and top speed. When you’re on a track and driving competitively, a handful of additional BHP is all you need over an opponent to outmaneuver them and pass them at a critical stage.
Torque on the other side gives cars a sense of power and can be used in real driving situations. When driving on roads with speed limits of 70-80mph, top speeds don't matter. However, torque is extremely useful for those who drive both in cities and the country.
Which Is the Most Important?
In fact, it’s quite hard to claim if the horsepower or torque is more important than the other, and that’s mostly because the two are also connected. It all depends on the purpose of your car.
We’ve discussed them above as though they are 2 individual and independent variables, but the fact is that they are not entirely independent of each other at all.
There is an old quote saying “Torque is winning races and horsepower is selling cars”. Although it may not be the complete truth, this statement does contain some truth.
To calculate horsepower (HP), multiply torque by the RPMs. Low RPMs can produce high horsepower from engines that have a lot torque. Although a low-torque engine can still make a lot of horsepower, it takes longer for the engine to reach its peak performance.
The main question about which factor is more crucial becomes difficult. The simple answer is you must have a mixture of these two factors to provide sufficient performance for all users. An automobile with no torque or apparent power is able to accelerate at a very slow speed. However, an engine with very high BHP and low torque will still be able to go fast - but that's only if it gets lots of fuel and then waits.
Another way to answer the question, as we’ve also touched on above, is through application. It is important for drivers to consider the purpose of their vehicles before they can decide if they have to use more BHP and torque. If you’ve ever noticed that farmers use a lot of diesel, for instance, they do so because their vehicles are usually all powered by diesel. Because diesel engines can produce greater torque than standard gasoline engines, this is why they are so popular among farmers. The farm machinery needs pulling power as well as torque force. They aren’t entering any races, so they’re focused on the torque delivery.
Driving instructors also tend to prefer diesel cars for their torque, mostly because it’s much harder for learners to stall a turbo diesel than it is to do the same to a gasoline car. They also require a high amount of horsepower to enable learners to drive at significant speeds.
Competitive racers require torque. However, horsepower is still the deciding factor. Any additional horsepower gives them an advantage in getting past an opponent at critical moments with an extra burst.
This brings us back to the frustrating question of BHP Vs. Torque. There’s no objective way to say which is more important, since it depends entirely on the needs of the driver. Understanding how they affect the vehicle's performance and capabilities is the best way to do it. Then, compare that information with your personal needs. If you do that, you’ll end up with the best-possible balance of BHP and torque.
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