Horsepower vs Torque – Explained


so this video is made to explain the difference between horsepower and torque now I’m going to start off by going a little into the math and the units of horsepower and torque and then I’m going to give you an analogy so that you can better understand what a car with a high torque means or a car with high horsepower means so horsepower is in units of foot-pounds per unit time for example if you were unit of time those minutes one horsepower would be equivalent to 33,000 foot-pounds per minute torque however is in units of pound-feet so horsepower is basically torque per unit time now there’s a direct relationship between horsepower and torque involving rpms there are revolutions per minute of your engine the engine speed so horsepower is equal to torque multiplied by our RPM multiplied for 2 pi one full revolution divided by 33 thousand foot-pounds per minute so this actually creates an interesting phenomena and so you’ve got horsepower is equal to torque times rpm over five thousand two hundred fifty two so this number right here is pretty important on a diameter when you look at the horsepower and torque here’s just a little fake one that I made up your horsepower will cross with torque at that RPM 52 52 and that’s because once your RPM exceeds 52 52 you’re going to be multiplying the torque by a number greater than one and that’s going to give you your horsepower so for example say we’re looking at 10,500 for rpms that your cars revving at pretty high but I’m just doing this for simplicity so you’re going to have 10,000 54 times your torque divided by 52 52 so your horsepower is going to be twice your torque at that rpm that will always be the case so at 5252 your horsepower then becomes greater than your torque and that doesn’t necessarily mean though that your torque will be going down they could both still be increasing but your horsepower is going to be greater than your torque once you pass 5252 and it will be less than your torque below 5252 um so what does this mean horsepower versus torque a good analogy just let’s just look at two engines so we’ve got a truck and a sports car the truck has a lot of torque but it’s low revving so it’s got low horsepower but it’s very strong a sports car has lower torque but it’s very high revving say 8,000 9,000 rpms so it’s got high horsepower but it’s weak now you can have a little analogy with um say a bodybuilder and a sprinter think of a bodybuilder as a lot of torque so say you put 50 pounds in a backpack on a bodybuilder and tell me run 100 meters he’ll run it in about the exact same time that he ran 100 meters without the backpack now Taylor sprinting around 100 meters and then put a 50 pound backpack on the Sprinter it was weaker and just built for moving fast and it’s got really going to affect his time so that’s a good way of looking at it as if you add weight to a sports car or a high revving low volume engine say like a 2-liter turbo it’s really going to affect its performance it’s not gonna be able to accelerate whereas you put a thousand pounds in the back of a truck it’s still going to accelerate relatively at the same rate