Horsepower and Tourqe

Can someone explain the two for me? ive tried google search, and everything that came up didnt make sense. Can any of you explain to me better?

Also, can you explain what RPM has to do with both horsepower and tourqe too?

Thanks alot guys

Caveat - blatantly borrowed.

Horsepower is a measure of the amount of Work the engine does over a given Time.

The basic definition of Work is:

Work = Force x Distance

Therefor: Horsepower = ( Force x Distance ) / Time

But what we are talking about here is the relationship between Horsepower and Torque. Torque is basically the force that we are talking about in the above equation. So if we substitute that, and clean things up a bit, what we are left with is the following equation:

Horsepower = (Torque X RPM ) / 5252

This actually tells us a lot of interesting things. The first is that at 5252 RPM, an engine’s Horsepower should equal its Torque. I think that you will find that if you look at pretty much any dyno plot of any car, the torque curve and horsepower curve will cross right around 5,200 rpm’s.

The next is that no matter how much torque our engine makes, the amount of horsepower that it produces is directly dependent on how fast the engine is spinning.

Ever wonder how a Honda S2000 can make 230 Horsepower, but less than 200 Ft Lbs. of torque? Well, the early 2.0 Liter S2000’s have a 9,000 rpm redline. If it is spinning that fast, it doesn’t have to produce a lot of torque to make a lot of power. If you plug 230 horsepower and 8,000 rpm’s into the equation above, you should find that you only have to make 150 Ft Lbs. of torque to generate that much power.

Now, the flip-side of this is a diesel truck can make 1000 Ft Lbs. of torque, but only makes 500 – 600 horsepower. This is because a typical diesel engine might have a redline of only 3,500 rpm. If you plug in 1,000 Ft Lbs. of torque, and 2,000 rpm’s in to the equation above, you should see that you would only be making about 380 horsepower.

Lastly, what this means is that there is no reason that an engine will make its maximum horsepower when it makes maximum torque.

So if we want to make more horsepower, we really have two choices. The first is to make more torque at a given rpm. The second is to make our torque curve fall off more slowly, or in other words to make more torque at a higher rpm. And actually, if we could get our engine to make the same amount of torque over a wider rpm range, that would also produce more horsepower.

Lastly, to get a sense of how torque and horsepower relate, here are a few comparisons keeping horsepower or torque constant over an rpm range:

200 Hp at 2,500 rpm = 420 Ft Lbs. of torque

200 Hp at 5,000 rpm = 210 Ft Lbs. of torque

200 Hp at 7,500 rpm = 140 Ft Lbs. of torque

200 Hp at 9,000 rpm = 116 Ft Lbs. of torque

200 Ft Lbs. of torque at 2,500 rpm = 95 Hp

200 Ft Lbs. of torque at 5,000 rpm = 190 Hp

200 Ft Lbs. of torque at 7,500 rpm = 285 Hp

200 Ft Lbs. of torque at 9,000 rpm = 342 Hp

horsepower makes you go fast.

torque makes you go fast quicker.

Yep. I have always gone off Horsepower is how much work the engine can do and torque is how fast it can do it.

Don't you mean the opposite?

I hate these discussions.

Horsepower is the result of an equation. Nothing more. Torque is the measurement of the power your engine is making. If normal internal combustion engines didn't spin faster than 5000rpm, no one would have even heard of the term "horsepower."

True definition of 1 horsepower is the power it takes to raise 33,000lbs 1 foot high in 1 minute. How does that apply to your motor? It doesn't.

Heard of a torque wrench? "yup"

Heard of a horsepower wrench? "no"

/thread

I hate these discussions.

 

Horsepower is the result of an equation. Nothing more. Torque is the measurement of the power your engine is making. If normal internal combustion engines didn't spin faster than 5000rpm, no one would have even heard of the term "horsepower."

 

 

True definition of 1 horsepower is the power it takes to raise 33,000lbs 1 foot high in 1 minute. How does that apply to your motor? It doesn't.

 

Heard of a torque wrench? "yup"

 

Heard of a horsepower wrench? "no"

 

/thread

Are you, by any chance, a hot 26 year-old girl?

Don't you mean the opposite?

mother fer. Yup. I got that one backwards.

In reality - it's the torque curve that's important.

You want it to be wide and relatively flat over a wide rpm range.

Below is one for the diesel:

http://i42.photobucket.com/albums/e344/dpmiller/curve.jpg

And here is one for the GT:

http://i96.photobucket.com/albums/l177/ean611/dyno2.jpg

lmao way to bring the debate here rao

I am just bringing knowledge that I learned from this forum to the discussion. If it was true in the other thread then surely it it true here. I also learned that slow cars are faster and fast cars are slower

In reality - it's the torque curve that's important.

 

 

And here is one for the GT:

http://i96.photobucket.com/albums/l177/ean611/dyno2.jpg

That looks like mine!!

COBB has released AccessTuner Race for free! Lets Share some maps!

Visit this page at COBB and submit the form with your AccessPort SS# and Cobb will give you the AccessTuner software for Free!!!

http://www.cobbtuning.com/info/?id=4431

Are you, by any chance, a hot 26 year-old girl?

Sorry, broskie. I'm a 24 y/o dood. Though, I do have plenty of girls to spare, but they're mostly in the 18-20 year range.

Caveat - blatantly borrowed.

 

Horsepower is a measure of the amount of Work the engine does over a given Time.

 

The basic definition of Work is:

 

Work = Force x Distance

 

Therefor: Horsepower = ( Force x Distance ) / Time

 

 

But what we are talking about here is the relationship between Horsepower and Torque. Torque is basically the force that we are talking about in the above equation. So if we substitute that, and clean things up a bit, what we are left with is the following equation:

 

Horsepower = (Torque X RPM ) / 5252

 

 

This actually tells us a lot of interesting things. The first is that at 5252 RPM, an engine’s Horsepower should equal its Torque. I think that you will find that if you look at pretty much any dyno plot of any car, the torque curve and horsepower curve will cross right around 5,200 rpm’s.

 

The next is that no matter how much torque our engine makes, the amount of horsepower that it produces is directly dependent on how fast the engine is spinning.

 

Ever wonder how a Honda S2000 can make 230 Horsepower, but less than 200 Ft Lbs. of torque? Well, the early 2.0 Liter S2000’s have a 9,000 rpm redline. If it is spinning that fast, it doesn’t have to produce a lot of torque to make a lot of power. If you plug 230 horsepower and 8,000 rpm’s into the equation above, you should find that you only have to make 150 Ft Lbs. of torque to generate that much power.

 

Now, the flip-side of this is a diesel truck can make 1000 Ft Lbs. of torque, but only makes 500 – 600 horsepower. This is because a typical diesel engine might have a redline of only 3,500 rpm. If you plug in 1,000 Ft Lbs. of torque, and 2,000 rpm’s in to the equation above, you should see that you would only be making about 380 horsepower.

 

Lastly, what this means is that there is no reason that an engine will make its maximum horsepower when it makes maximum torque.

 

So if we want to make more horsepower, we really have two choices. The first is to make more torque at a given rpm. The second is to make our torque curve fall off more slowly, or in other words to make more torque at a higher rpm. And actually, if we could get our engine to make the same amount of torque over a wider rpm range, that would also produce more horsepower.

 

Lastly, to get a sense of how torque and horsepower relate, here are a few comparisons keeping horsepower or torque constant over an rpm range:

 

200 Hp at 2,500 rpm = 420 Ft Lbs. of torque

200 Hp at 5,000 rpm = 210 Ft Lbs. of torque

200 Hp at 7,500 rpm = 140 Ft Lbs. of torque

200 Hp at 9,000 rpm = 116 Ft Lbs. of torque

 

200 Ft Lbs. of torque at 2,500 rpm = 95 Hp

200 Ft Lbs. of torque at 5,000 rpm = 190 Hp

200 Ft Lbs. of torque at 7,500 rpm = 285 Hp

200 Ft Lbs. of torque at 9,000 rpm = 342 Hp

Awesome. I've been trying to explain that equation to people for months but nobody around here would understand. That's why diesels have so much torque and so little horsepower.

An old saying,

Horsepower is how fast you hit the wall...

Torque is how far you take the wall with you.

Regarding dyno plots - this was my supra.

http://jsalmi.com/coolimages/dynoplot.jpg

http://img352.imageshack.us/img352/821/supraresizedfk0.png

I found a picture of your Supra!

I hate these discussions.

 

Horsepower is the result of an equation. Nothing more. Torque is the measurement of the power your engine is making. If normal internal combustion engines didn't spin faster than 5000rpm, no one would have even heard of the term "horsepower."

 

 

True definition of 1 horsepower is the power it takes to raise 33,000lbs 1 foot high in 1 minute. How does that apply to your motor? It doesn't.

 

Heard of a torque wrench? "yup"

 

Heard of a horsepower wrench? "no"

 

/thread

Torque is a measure of twisting force, so of course a wrench will be a 'torque' wrench and not a horsepower wrench.

Horsepower is a measure of (force x distance) / time, so when you turn the wrench you are generating HP.

http://www.vettenet.org/torquehp.html

Torque is a measure of twisting force, so of course a wrench will be a 'torque' wrench and not a horsepower wrench.

 

Horsepower is a measure of (force x distance) / time, so when you turn the wrench you are generating HP.

 

http://www.vettenet.org/torquehp.html