Who's faster? Explained and Simulated - Horsepower vs Torque
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Published 2023-08-20
Well that’s the question we will answer today and by answering it we will gain a more profound understanding of horsepower torque and vehicle dynamics and possibly also a headache. So let’s get started
Now these numbers are peak torque and peak horsepower numbers but before we use them we need to know at what engine rpm do these peak numbers occur. To make things fair we will say that peak horsepower and peak torque occurs at the same rpm for both vehicles. So let’s just say that peak horsepower occurs at 5000 rpm and let’s say that peak torque occurs at 2500 rpm.
Now if you already know a bit about torque and horsepower you might be able to tell that there’s something wrong with one of our engines. And to demonstrate the issue as well as our first lesson of this video I will use this convenient little formula and it says that horsepower is equal to torque times rpm divided by 5252. The same formula for metric units would be Kilowatts equal torque in Nm times rpm divided by 9549, but I’ll be using imperial units today because later in the video we’ll be plugging numbers into a simulation software that’s programmed in imperial units. But the lessons and concepts explored in this video are completely independent from and are equally valid whether you use metric or imperial.
Now we’re going to learn something about horsepower and torque by demonstrating how our horsepower biased engine is actually impossible. We will then fix this engine to make our drag race fair and possible.
Let’s say that we want to find out what kind of torque this engine generates at peak horsepower rpm which is as we said 5000. So according to our formula 1000 = x times 5000 / 5252. If we solve for X This gives us 1050.4 pound feet of torque. Which is higher than our peak torque of 500. Things don’t add up. As you can see from our simple formula horsepower is torque times rpm divided by a constant, so horsepower is essentially torque times rpm. In other words horsepower within itself contains both the amount of torque and the frequency of torque application. In the simplest terms possible: horsepower is torque over time where time is represented by rpm, rotations per minute.
So if we are achieving 1000 horsepower at 5000 rpm than our peak torque simply cannot be 500 pound feet. And that’s because horsepower is a product of both torque value and frequency of its application. If both torque and the frequency of it’s application is high then horsepower will of course also be high. It is impossible to have high horsepower with very low torque. The only way to achieve that is to make up for the low torque with a very high frequency of torque application, or very high rpm. If you can’t punch very hard then you have to deliver more punches im the same period of time to deliver the same amount of damage.
In our case we have a high horsepower figure, 1000 at a relatively low rpm, 5000, and this tells us our torque must be high. In other words we’re dealing a lot of damage with a relatively low number of punches and this tells us that each of our punches definitely packs a punch. This teaches us how torque, horsepower and rpm are inter-connected. It is incorrect and misleading to try and observe and compare them isolated from each other.
So if we want to have a 1000 horsepower and 500 pound feet of torque engine then peak horsepower cannot be delivered at 5000 rpm. If we want to do the same damage but keep our punches weak then we must increase the number of punches delivered.
A special thank you to my patrons:
Daniel
Pepe
Brian Alvarez
Peter Della Flora
Dave Westwood
Joe C
Zwoa Meda Beda
Toma Marini
Cole Philips
#d4a #horsepower #torque
00:00 Explanation
05:40 Simulation
11:56 Results
All Comments (21)
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This man always sounds like he's recording at 1am and trying not to wake up his roommates
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Something that wasn't considered : if you make a lot of horsepower at high rpm, you can use shorter gearing to have higher wheel torque and still benefit from the high hp figure.
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Love the analogy of Torque = damage per hit, HP = DPS. A lot of people that are knowledgeable with cars will keep parroting that "torque = acceleration and power = top speed". Engine performance is 100% determined by power in the power band. People are under the impression that low torque is unresponsive but that's because casual drivers avoid the sound of high RPM.
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i love how calm you are and how you talk with a low voice, it is soothing to watch
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I'm a race engineer. It's a little different now, but we used to change intake trumpets and exhaust lengths to change the power curve and we had about 40 ratios to choose from (5 speed gearbox) to optimize the rev band. The goal is to achieve the highest average engine power per lap, or greatest fuel consumption (a good surrogate), which usually means you're the fastest.
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easily the best automotive science channel on youtube. your ability to efficiently breakdown concepts with effective examples is so helpful to anyone learning about automotive technology.
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But why is he whispering
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You’ve explained something that I have been wondering in a long time in just 14 minutes perfectly for newbies, kudos to you sir!
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The punches explanation is actually awesome, as it helps describe how transmissions work. The horsepower you put in to the transmission is the same as the horsepower you get out, so the same damage per second. But in first gear, you do less frequent but more powerful punches. In higher gears your damage is reduced but your attack speed is increased! Same damage output, different speed and torque. Thank you so much!
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The reason the high torque car is faster in some of the scenarios is because it actually has more horsepower than the high horsepower car at the rpms the cars are being forced to operate in. At 2500rpm the high horsepower car only has half the horsepower of the high torque car (because it has half the torque at the same rpm).
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This is absolutely fascinating and a wonderful explanation. Thank you!!. Just amazing how you always explains everything so clearly. Thank you!.
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Thanks man.. I've been a car guy forever, but never really properly understood the difference until now. Appreciate you making this 🤌🏼
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Refreshing to hear someone talk about this who actually understands that power and torque are not independent of each other, but in fact fundamental to each other. So many people just don’t understand it, and also don’t grasp the fact that a peak number is only telling a fraction of the story. Good work.
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Your delivery is so relaxing
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This is such a good video and you are an amazing teacher. I have watched a few of your videos and it is easy to see why you are getting a million subscribers. I'm happy for you and cheering for your continued success. Thanks for the content.
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I think a pretty good way of tackling the subject would be comparing two engines that make the same horsepower but at different RPMs (for example 700 HP @8000 RPM vs @2000 RPM); naturally the transmission ratio should be varied accordingly. Nice content as always :)
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Amazing video. I already knew this but I've never seen it illustrated in such a straightforward manner and really enjoyed it as always. The punching analogy is just genius. Would love to see a video on tires and grip, ie bigger tires, stretch vs bulge, lower profile with more unsprung weight vs smaller wheels with a higher tire profile. I must confess I feel like I know frighteningly little about which of the aforementioned factors/choices are best for performance for a car enthusiast.
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Good explanation. Thx for such an effort you've put into this. Subscribed
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Great video! I haven't ever seen your channel before this video was recommended to me, but this was something I really struggled to understand growing up. I wish I had a video like this to learn from 10 years ago 😂 I really liked the analogy with the punches/damage done too. Thats a great way to explain it to someone who has a hard time understanding the difference.
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Over thousands of videos of simar subjects over the years... this is the perfect and most definitive explanation of what torque and horsepower really mean. You sir are brilliant, keep at it! ❤
