What's the difference between torque and horsepower?

This is hard to explain in good o'l American units, so excuse the metrics.

Watts = Newton Meters per second = power. One watt is 0.00134102209 hp

Torque = Newton Meters only.

To make it easier to understand power is equal to force times velocity. Torque is the radial force and power is multiplying with the revolutions per minute.

So here is the formula Power in kW = (2x Pi x RPM x Torque in kN)/60

It follows that a motor with a lot of torque like the Hayabusa can push more power at low RPM compared to 1K that needs to get the RPM much higher to deliver the same power.

If you arm wrestle with a guy who has bigger muscles, he will exert more torque and kick your butt.

If you ride a bicycle against a guy who has 30% stronger legs than you, (more torque) but you can spin the the pedals 40% faster than him, you will put out more power and kick his butt.
 
Tq puts you in the back of the seat hp keeps you there.

Just think of the Tq as your low end power and hp is more upper end.

Because of the formula they are equal at 5252rpms and that's when tq starts going lower and hp goes higher.

Edit tq could still go up but hp will always be higher then tq after 5252rpm
 
Torque is a force acting about a center of rotation at a fixed distance. Nothing is moving. If you put a breaker bar on a spindle and push on the ar one foot out from the center with a force of 100 pounds, you are applying 100 foot pounds of torque. Get a 2 foot breaker bar and you are generating 200 foot pounds of torque.

Horsepower is a unit of work. Something has to move in order for work to occur. Once that spindle starts to turn you have horsepower (Horsepower = (Torque X RPM)/5252) You continue to apply that 100 pound force as the spindle turns and accelerates. As it speeds up you are doing more work and are making more horsepower. Now you are thinking "hey, I'll just use the 2 foot breaker bar and make more torque, and therefore more horsepower". Yea, well you are able to accelerate the spindle faster but soon find out that you can't go any faster. If you had that 1 foot breaker bar you could do more rpms. In the end, with either bar, your body can only generate so much horsepower (work) so the formula comes out the same either way. The 2 foot breaker bar gave you more torque multiplication, but not more horsepower so you could accelerate that spindle quicker at first.
 
I was gonna use the wall example, but had I actually read all the previos replies I woulda seen it had been done! Therefore I second the wall reply!
 
HP = Top speed
Tq = How quickly you get there.

Not picking on you specifically, but these generalizations really aren't right. The relationship between hp and torque is a fixed mathematical formula so you can use hp and torque interchangeably at any rpm as you describe the outcome.
 
Example 2012 FJR1300 moded to hell 102 pounds of tq 60" wheel base and 0 to 60 in 2.6 seconds , but 0 to 100 everything has killed it . 120 hp stock
1300 hayabusa same 0 to 60 , amazing 0 to 100 , and still pulling like a bullet .

Both bikes have same Tq but the later has 40 plus hp in stock form , 50 plus with mild moding .
 
Not picking on you specifically, but these generalizations really aren't right. The relationship between hp and torque is a fixed mathematical formula so you can use hp and torque interchangeably at any rpm as you describe the outcome.

OP said explain it simply :)
 
OP said explain it simply :)

Sure, but not simply incorrect.

Torque is what you see on a torque wrench when you torque a bolt and hold it still at the required torque. Power happens when you see torque on the torque wrench while you are turning the bolt.

"HP = Top speed
Tq = How quickly you get there."

Both those statements are totally incorrect.
 
The "SIMPLE" description of the relationship between torque and HP is:

Torque is what does the work
Horse Power is how quickly the work is done

The next step in Motorcycling is learning how this relationship affects traction and how to manage that traction with the throttle. In the classroom we call it "Powerband Management" !
 
HP = Top speed
Tq = How quickly you get there.

This is the most accurate and clear simple answer ive seen yet! Hp determines what your top speed is, Torque determines how quickly you reach top speed!
Thats what makes the Hayabusa such a beast is the insane torque AND horsepower!



 
Last edited by a moderator:
This is the most accurate and clear simple answer ive seen yet! Hp determines what your top speed is, Torque determines how quickly you reach top speed!
Thats what makes the Hayabusa such a beast is the insane torque AND horsepower!



Not accurate. Neither determines either or both determine both. Take your pic. It's a circular argument.
 
Last edited by a moderator:
Back
Top