Lets Get TECHNICAL!!!

[1987HondaAccord]

Hey...

I was hoping someone out there could give me a really technical explanation of the difference between horsepower and torque. I know torque is measured in ft. lbs. but what exactly is horsepower measured in? What do both of them mean in terms of acceleration?

thanks is advance.

[Jareds 89 LX-i]

Here's a pretty decent explanation....

http://www.clubhonda.com/6/ubb.x?a=tpc&s=316602881&f=274606891&m=9176073502


I've seen others too, but I've forgotten where they were :rolleyes:

:)

[smufguy]

okay, me being a lousy Mech Engg student, lemme try to explain.

Horsepower, that is widley used, is actually a unit of power. As you may recall in Europe, they measure it in KW (Kilo Watt). Power is how much work you can do in a given period of time. And if you say your car has 120hp, In abstract sense, it means that your car has the work power of 120 horses. So higher hp means, you can get a lot of work done, in a given period of time

Torque in very basic sense Force X Radius. This is because torque is an angular force, ie it acts on the surface creating a moment about a fixed point, which in daily use is an axis of an object. Having a larger torque means you are strong. Its just simple as that.

So you gotta have a decent amount of torque and a decent amount of hp to have a good acceleration. Thats the key to Know where ur car makes its peak hp and thats where u wanna have ur rpm around if ur racing someone.

[anchovies]

For the lazy ppl,
torque is what you feel and pushes you back in your seat when you accelerate
hp is derived from torque.

[AvgWhtMale]

Yeah, torque is basically the force that pulls the car along and pushes you back in your seat. The more the car pulls, the more torque it has. Horsepower is how fast the engine can deliver torque. In fact, it is torque times RPM (divided by a factor, which I think is 550). So cars with lots of horsepower, that means they can deliver torque at high RPM's, like VTEC engines. Torque is roughly equivalent to how much an engine can pull. Big cars need lots of torque. Horsepower is roughly equivalent to how fast it can pull. Race cars need lots of horsepower. If you want a big car to be quick, you need torque AND horsepower (and stock in oil companies).

[Einstein]

Torque is like a person with strong legs.

Horsepower is like a person who can run very fast.

[AvgWhtMale]

Horsepower is a unit itself. That is, horsepower is measured in "horsepower." It is a unit of power, as mentioned above. 1HP is roughly equivalent to the amount of power that one horse takes to plow one acre, or some such nonsense (blame the Brits). Nobody uses it except motor heads. As for acceleration, both torque and horsepower help. High torque gets you off the line in a hurry. High horsepower means you are still banging out torque at high RPM's (i.e. still accelerating), while the other guy has to upshift (the credo of VTEC). For most the engines mentioned in 3geez, you'll notice the torque is relatively low (100-120) even though horsepower can approach 200 (for the B18C5, I think). This is because our cars are relatively light compared to what is out on the road today, so not a lot of torque is required. An exception is the B20Z and the other CRV engine, which have on the order of 140 lb.ft of torque. Why? Because CRV's are bigger than Civics and Accords. They need more force to get off the line. It can be confusing, but it does all make sense eventually.

Just remember, when you are looking at a torque curve (torque vs. RPM), you are seeing all you need to know about the engine. If the torque stays high as RPM's get up there, then you know you've got lots of power and you can put on the beeotch slap down at the track on Sunday afternoon.

Sorry for the lengthy explanation, but I'm a mechanical engineer. Ask a geek a technical question and...

-A Geek

[AvgWhtMale]

That's a good way to put it, Einstein :)

[Einstein]

Originally posted by AvgWhtMale
That's a good way to put it, Einstein :)

I'm a Mechanical Engineer, but I get tired of doing reports. You'll find people just want the bottom line anyway.

[AvgWhtMale]

Good point.

[Einstein]

Here is a technical discussion of torque vs. horsepower:

http://www.s2ki.com/forums/showthread.php?s=&threadid=106592

[1987HondaAccord]

thanks for the tip...

That's pretty Technical!!

[ACCORD EX]

some nice relations >

1 HP = 75 KG.meter/second = 550 lb.ft/second = 746 watt

hope this helps anyone !