How Horsepower Is Measured In Cars

How Horsepower Is Measured In Cars


This car is spinningup to a whopping 8,200
revolutions per minute.At 8,200 rpm, it screams.It’s a Ford Mustang GT350,and though its wheels are spinningat what should carry the car to 140 mph,it’s obviously not moving anywhere.But what you’re seeing
is an important testthat helps us understand
what the car is capable ofand, in this case, could
even help Ford decidehow much they could sell it for.It’s impossible to watch a car commercialwithout seeing torque
and horsepower numbers.Commercial: Bred to deliver 412 horsepowerand 390 foot-pounds of torque.Narrator: Car manufacturers
would have you believehigher horsepower and torquetranslate to “faster” and “stronger.”That’s not exactly true.What those two numbers do, more precisely,is give us an idea of
what a car is capable ofin different road situationswithout having to see the car in person.Before we examine how horsepower
and torque are measured,let’s break down what they are.Simply put, torque is
the capacity of a forceto twist something.Think of a torque wrench, where you fitthe mouth of the wrench to a boltand push down on the handle.The wrench’s ability to
turn the bolt is torque.The same exact twisting
action is happeninginside of a car engine, except, this time,instead of your hand and arm
pushing down on the handle,tiny explosions happen
inside each engine cylinder,pushing a piston down that
causes the crankshaft to rotate.No hands required!Torque!The harder this piston
pushes on the crankshaft,the harder the crankshaft spins,the more total energy a
car’s engine puts out.So, to recap, in the case of our car,torque is how much force
an engine produces.How does horsepower relate?Well, if torque is how much
force an engine produces,horsepower is how quickly
it can produce that force.So, we have a bunch of horsepower.What can we do with it?If we have, say, 5 horsepower,we’ll have enough to
move a 2,750-pound carone foot in one second,given weight and power
are the only two factors.If we had a heavier car, we would needmore horsepower to move it one foot.So, how exactly does one
measure torque and horsepower?Well, engineers use a
device called a dynamometer,of which there are a couple of types.This dynamometer, called
a chassis dynamometer,is a treadmill of sorts for cars.Here, the car’s wheels sit on a rollerthat lets the wheels spin without causingthe car to go anywhere.Various amounts of weight, or load,are applied to the car using straps.With the car chained
down, an engineer pusheson the gas pedal to see
how the car interactswith each load at a different rpm.The dynamometer outputs a
chart that looks like this.On it, two lines are plotted:a line for torque and
another for horsepower.Peak torque is where the
engine produced the most force.Peak horsepower is where
the engine producedthe most force the most quickly.The figures for torque and horsepowerthat are put on dealership stat sheetsand in commercials are, generally,the numbers at the peak
of each of these lines.While big torque and horsepower numberson a stat sheet surely are impressive,they only clue a new
car buyer into a coupleof many facets of a car’s personality.Those numbers, though, are
still the best ones we’ve gotof telling how capable a car really is.

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About the Author: Oren Garnes

100 Comments

  1. that was very basic and soo un-informative LOL its like explaining cars for toddlers. I'm sure your audience have slightly more IQ to understand more complex information regarding torque and horsepower…

  2. thank you, business insider, for providing me with the knowledge that I never knew I needed, nor questioning it and present it in a very informative, easy to understand and interesting way

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  4. Maybe mention that factory horsepower ratings are measure at the engine crank not at the wheels like the video implies.

  5. 4:24 …(HP and torque) those number are the best one we have for telling how capable a car really is.
    0-60: Am I a joke to you?

  6. Dude. It's a SHELBY MUSTANG GT 500 . Don't call it Ford Mustang. Shelby models, Shelby tuned cars are whole different game.

  7. you didnt explain how the companies mislead you with the power numbers, they rate it at the crank, not to the wheels of the car so really its not 760 horsepower to the WHEELS its to the CRANK which is misleading

  8. For mustangs, horsepower is how fast you will hit the wall, and torque is how many people you will drag with you.

  9. The guy speaking in this video sounds like he doesn't know a lick about cars.

    BI should just stick to business related topics.

  10. Well, manufacturers usually advertise Brake horsepower (bhp). This is measured at the crankshaft just outside the engine, (with the engine outside the vehicle and no auxiliary components [alternator, water pump, etc..] attached) before the gearbox and drive train.
    The Wheel Horsepower (whp) numbers are ALWAYS lower than what's advertised.
    The Challenger Demon is advertised at up to 840HP but only puts out around 700HP at the rear wheels.

  11. they tie a string to a horse and see how much power the horse has to use to pull the car. thats how they check for horsepower

  12. Certified motorcycle mechanic here. Fuel doesn't explode inside the combustion chamber. It burns. The dynamometer load is applied by the rollers and not the straps. Please get your facts straight before misinforming the general public.

  13. They didn't mention drive train loss. Crank vs Wheel Horse Power. I can already see the clickbait they can do with it "CAR DEALERSHIPS ARE LYING TO YOU ABOUT HP!"

  14. horsepower is fake if you take one care that has 350 hp and tie a rope to it vs 350 actual horse on the other end of a tug of war no way that car will even come close so its fake

  15. As a car guy I can speak for all car guys and say thank you for explaining things that matter to us to other people. But you forgot a few things like that some other manufacturers hp and lb-ft are measured at the crankshaft rather than the wheels. Let’s say that 707hp Dodge Challenger hellcat you showed actually has about 650 to the wheels. Basically wheel hp is just crank hp after taxes. But great work on the research

  16. Electric r future more horsepower and torques and it decides it is cheaper it is just a different way of thinking and building manufactuing a car so I never wonder to be a knowledgeble person of engineering the engines but different way to be knowledgeble of a Tesla motor. Horsepower decides how many it sells but the Tesla more horsepower but cheaper and why horsepiwer is about how fast u produce the power?

  17. When I saw them took apart the things of a Tesla motor I felt they r very knowledgeble about things but when I felt they r good and deep in something I felt hard to stand the Tesla side I think go took apart engines r good and knowledgeble too u dont have to do that

  18. "Those numbers are still the best ones we've got to tell how capable a car is" 4:23. Just look up 0-60 and 1/4 mile times, there are a lot of better ways of looking into a car's performance.

  19. As an engineer, I loathe the fact that they omitted the torque-axis in the last graph. The graph they used had a vertical horsepower line and a horizontal RPM-line. If you're going to plot two lines in one graph, make sure to include the proper axis!!

  20. Lmao the americans XD
    6.2L Supercharged V8 and all that is just for some 760HP XDDDDDD outta friggin 6.2L V8 thats some weak ass engine a 5.0L V8s with twin turbos coulda like 1360HP and 4.0L with 2 Superchargers around like 1156HP in Zenvo cars XD

  21. This is a very pointless video. All this does is tell that vehicles are dyno tested, and a little about torque, but doesn't explain anything beyond that. 2.28 million subs and this is the garbage quality content you produce? What has this world come to?

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