Love this guy. Love his channel. This video is so relevant for this forum.

In canada, we're buried in snow. Two months left before i get my bike back.

 

Good info, thanks for posting.

 

He does have one small mistake. He states you can not have one with out the other.

That is not true. You can not have horse power with out torque, and that part of his statement is true.

You can however have torque with out horse power. To be simple lets say a bolt is tightened to 100 lb-ft of torque. I can use a torque wrench and try to turn the bolt, but if I only use 80 lb-ft of torque the bolt does not turn. Torque was applied, but the bolt did not move. There for there is no horse power. Horse power is the measure of the rate of work.

 

I think as applied to an internal combustion engine, he's mostly correct if the engine were to stay running. In that case, just as your torque wrench scenario, if there is not enough torque for HP to be measured, then the engine stalls. It just won't run.

Horsepower is a fairly glamorous term for torque X RPM, and what a lot of people focus on. For our purposes, I believe that torque is the important number. Without that, we go no where!

But it is fun to say "She's makin' X amount of horsepowers on the dyno!"

 

The way I think about it is:
Torque is the force that gets you going (overcoming inertia)
Horsepower is the force that keeps you going (or going faster)

 

I get the question all the time "How much horsepower is this transmission rated for?" It's not, it's rated for torque.

 

“Under-steer is when you hit the wall with the front of the car and over-steer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you.”
-- Jacques Schnauzee "World Famous Racecar Driver"

and here is a good explanation about ABS:

 

Or more simply stated:

Torque is force applied to a lever arm about a pivot point.
Horsepower is what let’s you spin it at certain speeds.


For example. If you put a breaker bar with a socket on an axle nut. And you apply 10 lbs of force at 2’ from the nut, you have applied 20 ft-lbs of torque.

Then assuming you are not loosening the axel nut, but turning the drive mechanism with the same 20 ft-lbs of torque, it will take a certain amount of horsepower to turn it at 100 RPMs, and it will take more horsepower to turn it faster.

Edit: and a simpler example:
* Torque gets a vehicle up a hill
* Horsepower enables that vehicle to climb the hill at certain speeds.

 

It's why nineteenth century steam tractors outpull modern tractors. All that torque at low rpm.

 

I was told that Horsepower is how hard you hit the wall. Torque is how much of the wall you take with you. Just what I was told. Carry on.