Horsepower vs Torque - A Simple Explanation

**Understanding Torque and Horsepower: A Comprehensive Guide**

Welcome everyone! Today, we will delve into understanding the distinction between torque and horsepower. This discussion will avoid complex analogies and minimal math, focusing instead on theory for easy comprehension.

### What is Torque?

Torque can be described as a force applied at a distance. Imagine using a wrench to tighten a bolt; when you apply downward pressure, the length of the wrench (the distance) multiplied by your force creates a twisting motion—this is torque. Similarly, in an engine, combustion forces the piston down, which exerts pressure on the crankshaft. The combination of this force and its distance from the crankshaft's center generates the engine's torque.

Torque can be manipulated through gears or leverage. For instance, using a longer wrench increases leverage, thereby enhancing torque. This principle explains how engines produce power—combustion creates downward force, which, combined with the piston's distance from the crankshaft, results in rotational force (torque).

### The Relationship Between Torque and Power

Power is defined as the rate at which work is done. Moving an object over a distance requires work; doing it quickly necessitates more power. In the context of engines, power is determined by how fast torque is applied—this is measured in revolutions per minute (rpm). Horsepower, a unit of power, is calculated by multiplying torque (in pound-feet) by rpm.

To illustrate, consider moving a car from one point to another. Doing so slowly requires less power, whereas moving it quickly demands more. This translates to vehicle performance: higher horsepower enables faster acceleration and quicker work completion.

### Torque vs. Horsepower in Vehicles

Let’s compare two identical vehicles with different specifications:

- Vehicle A: 200 horsepower and 100 lb-ft torque.

- Vehicle B: 100 horsepower and 200 lb-ft torque.

Vehicle A, despite having less torque, will accelerate faster due to its higher power. Power determines how quickly work is done, enabling faster acceleration. While Vehicle B has more torque, it can still achieve comparable performance by using gears to leverage its power effectively.

### Torque and Horsepower Curves

Manufacturers often provide peak horsepower and torque figures, which are specific points on broader curves. A torque curve shows the engine's torque output across different rpm ranges, peaking at a certain point. Similarly, horsepower peaks elsewhere on this spectrum.

In practical terms, staying in a particular gear allows you to experience maximum torque at its respective peak rpm. However, achieving optimal acceleration may require adjusting gear ratios to align with peak horsepower rather than peak torque. For example, continuously variable transmissions (CVTs) adjust gearing to maintain engine operation near peak horsepower, maximizing acceleration.

### Conclusion

Torque is the force applied at a distance, crucial for creating rotational motion in engines and other machinery. Horsepower, on the other hand, measures the rate of work done—how quickly torque is applied. While both are interdependent (horsepower = torque × rpm), understanding their relationship helps explain vehicle performance.

In summary, while torque provides force, horsepower determines how quickly that force can be utilized. This distinction highlights why vehicles with higher horsepower often accelerate more swiftly, even if they have less torque, as gears can amplify their power for optimal performance.

"WEBVTTKind: captionsLanguage: enHello everyone and welcome. In this video we're going to be talking about the difference between torque and horsepower.And we're not going to be using any strange analogies and very minimal math; just talking about theory and keeping it easy to understand.So we'll start things off with torque.Torque is simply a force applied at a distance.You can think of it as a twisting force. So if you're trying to tighten something down using a wrench,You apply a force, you press down at a distance, the length of that wrench, and that supplies a torque at whatever you're tightening.Same idea with a socket wrench. So if you're tightening down a bolt you apply a force at a distance,And that supplies a torque to that bolt to fasten down that bolt.Now the same thing is happening with your engine.So combustion within your cylinder is what's supplying the force pressing this piston down, and then that piston is pressing down on a crankshaft.So as you can see, you've got your force pressing down,You've got your distance where it's pressing on the crankshaft, the axis of rotation is the center here the piston is pressing offset from that center so at a specific distance andCombined that gives you your engine torque, force pressing down at a specific distance that gives you a twisting forceThat's the torque that your engine is making now torque can be manipulated very easilyBy using gears or by using leverage for exampleSo this will supply you know with the maximum amount of force I can supply to it a certain amount of torqueBut then if I were to use something much longerNow I have more leverage I can press at a greater distance and since torque is force multiplied by distanceThe torque here is going to be significantly greaterOkay, so what is power and how do these two relate? Well, power is the rate at which work is doneSo what does that mean? Well if I move this car from here to here. I've done a certain amount of workI've moved this from here to here, now if I do it very slowlyit doesn't require much power. if I do it very quickly it requires more powerNow ultimately I'm accomplishing the same thingI'm moving the car from here to here, but I'm doing it fasterThe rate of work is greater thereforeIt takes more power so more power going quickly than going slowlySo power ultimately is what gives you speed, what gives you acceleration now the two are connected so in in our contextHere looking at our engine. We have torque as a force pressing down acting at a distanceWell how fast that's happening is our power so that's our rpm. So horsepower is torque multiplied by rpmSo how often this interaction is occurring...And so how fast is this spinning while we're still getting that consistent force acting on the piston so the faster it spinsSupplying that same amount of force at that same distance the more power we're going to makeOkay, so how about an example to help explain things further?Let's say we have two different vehicles that are exactly the same. Now, I know these look different, but we're just going to pretendThey're exactly the same nothing about them is different except this one has 200 horsepower and a hundred pound feet of torqueThose are the peak numbers. This one has 200 pound feet of torque and a hundred horsepower so half the powerTwice the torque this one has twice the power half the torqueWhich one is going to accelerate faster assuming both of them have the same mass?And everything else about them is equalWell the one with more power is always going to be quicker because that is the rate at which work is doneThat's how quickly it can accomplish work move something from one place to another it can move it fasterNow this one has more torque, greatBut as we know torque can be manipulated through gearing so gears act just like leverageSo while this doesn't have as much torque as thisIf I'm applying torque to something I - my power doesn't change, how strong I am doesn't changeBut I can use leverage just like cars can use gears to make more torque so this car with twice the powerBut half the torque can use gears to accelerate faster, so it can use a longerYou know leverage arm a greater a more aggressive gear ratioSo that it can put that power down and ultimately because it makes more power it can do more work more quicklyIt will be the faster car.Okay so now let's talk about horsepower and torque curves because when a manufacturer gives you a horsepower and a torque figureThey're just giving you the peak figure for each of thoseThey're not giving you, you know the amount of torque that that produces across all of the engine rpm rangeAnd so if you look at a torque curve, it'll have some peak along that curve with respect to rpmso that's the engine rpm in which the force pressing down on the piston is at its greatest so that's peak torqueand what that means if you stay within a set gear, if you're in one gearlet's say you're in third gear, you will feel the - the force pressing you against your seat will be the greatest at peak torque nowThat's assuming you're staying at a constant gear ratioYou're staying within one gearSo now if you look at the horse power curve overlaid over that torque curveAt some point, peak horsepower will occurAnd that's when the engine is doing the most amount of work it can do and so at this pointYou may think okay if I want to accelerate fastestI need to be at peak torque, so you want to be at that peak spotWell, that's only true for a set gear and that's only within that gear if you can manipulate the gear ratioLet's say peak torque is right hereBut peak power is over here, later in the RPM range you can sacrifice torqueBut get a more aggressive gear ratio, and ultimately accelerate more quickly by accelerating at peak powerSo why is that well that's because you're multiplying your torque by the gear ratioSo you have peak torque multiplied by a lower gear ratio versus a lower torqueBut multiplied by a significantly higher gear ratio at peak horsepowerThat will give you your peak accelerationSo for example CVT transmissionsWhich can adjust the gear ratio constantlyIf they adjust that gear ratio to maintain the engine at peak horsepowerThey will accelerate the fastest rather than if you were to manually shift gears, or have an automatic transmissionWhich shifts between gears and you'll feel that peak sensationthat peak force against the seat at peak torque as you cross over it, but the actual true amount of peak accelerationThat's possible with that engine would be if you manipulated gearing if youManipulated leverage to allow you to be at the highest horsepowerLevel with the most aggressive gear ratio possibleso a quick review, torque is simply a force acting at a distanceHorsepower is how quickly you can accomplish work, now both of them require each otherThey're a function of each other horsepower is torque multiplied by rpm, so you've got a specific torqueand then you spin the engine at a certain speed, that will give you powerAnd so ultimately they are you know they require one another you can't have horsepower without torqueBut the most important figure if you're looking at \"how fast will a car be able to accelerate?\"\"What will its top speed be?\" that comes down to power because that's telling you how quickly?Can you accomplish a certain amount of workSo hopefully this has cleared things up; the differences between torque and horsepowerIf you have any questions or comments, feel free to leave them below. Thanks for watching\n"