Horsepower vs Torque - Explained

What's the difference between horsepower and torque? What does it mean to me? An explanation of horsepower and torque, and a way of explaining it so everyone can understand what they mean. Cars with high torque are powerful and strong; cars with high horsepower are fast, but ultimately it all depends on gearing.

NOTE 1: The G force you feel when accelerating is 'proportional' to the torque curve at the wheels, not the engine torque or horsepower. The engine torque is quite meaningless by itself, because it is modified by the gearbox and final drive, but losses withstanding, it does determine what people 'feel'. Torque is a force, and hence produces thrust. Horsepower is not a force, and does not magically 'take over' at some point as some people seem to imagine. Think wheel torque!

NOTE 2: Looking back, the analogy wasn't such a good idea; what I implying is that many vehicles with high torque that are geared low tend to be heavy, so added weight affects them little, where as small engines have lower torque, but rev higher, and are used in lighter vehicles where additional weight makes a large impact.

Category:

Autos & Vehicles

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• torque
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[andrewcovie]

you earned yourself a sub! ,fair play good work

[EngineeringExplained]

@andrewcovie Woohoo! Thanks!

[StefSyros]

@EngineeringExplained Ok! I thought about it before and understood it completely,so i wanted to get online an correct my self..

What i wanted to say is that the point where the highest torque of an engine is,is the most officient way to drive it in terms of energy you give and energy you get,so every hp you get before or after that,it may be less or more,but in order of consumption/torque it wont be officient...

the 5252 mark confused me a little bit...Is this just a theoretical number?

[EngineeringExplained]

@StefSyros Umm, well the number is based on the definition of horsepower. 1 hp = 33000 ft/lb-min / (2*pi) = 5252. And based on the equation, this is where the two will always meet. However, it is important to note the HP and Torque are measuring different things, they do not have the same unit. So saying they're "the same" at 5252 rpm isn't really accurate, it's just where it occurs.

[StefSyros]

So..simple said,at 5252 rpm its the most officient way to opperate any kind of ICE,cause then you get the best analogy of torque/HP for the minimum possible fuel??

I mean,everything less than 5252 would give you off course less fuel consumption,but you wont get the maximum amound off power from it??And everything more than that would produce more power ok,but with more energy needed to produce it??

I dont know if i understood it right..

[EngineeringExplained]

@StefSyros Uhh I wouldn't necessarily say that. At greater RPMs, there is an increase in friction. The more friction you have, the less efficient your engine is. I believe there are some hybrids that have a setup with the engine running at a constant rpm, and I think they're in the 2000-3000 rpm range, this being this specific engine's most efficient range.

[RFID666]

Great explanation. This kid will go far

[EngineeringExplained]

@MrAxmea Fluffy kitten videos are probably a better option at 3 in the morning.

[saurabhreigns]

u r jus 2 good at explainin things....really very helpful ...:)

keep up the good work.:)

[MK3504]

Awesome videos! Just subscribed

[William9alex]

great videos

[desertfox2020]

Also, I've heard of some engines producing their bhp and max torque at the same RPM, is there any specific reason why this sometimes happens, but not always? Is it all down to valve timing?

[desertfox2020]

Something I'm not quite clear on, If I understand you correctly you would accelerate faster holding the RPM at which you get max torque, regardless of the gear you're in? Ex. If I'm entering the freeway, my truck makes 300 lb/ft of torque @ 3200 RPM. To get up to highway speed ASAP, is it best to hold the engine at that RPM and build speed, or just let it go up to about 4k, when it will shift up and fall back to 1750 and continue like that?

[StefSyros]

@EngineeringExplained Well i never said it was the same thing but for sure the one depends of the other. A nice easy way to show it, would be with a long crankshaft and a short one...that shows both torque and HP in each case...

Ok i get the 5252 number...thx