Im having a debate can someone explain what is torque and how it applies to cars ?

 

torque is an instantaneous force. It's how hard the crank can twist.

horsepower is a measure of power. How much work you can do in a given time.

Properly set-up, the car with more power will always win.

hope that helps in your debate...

 

Imagine tightening a bolt with a wrench. The harder you pull on
the wrench to tighten the bolt the more torque you are applying.

It is the rotating force created by the engine which is applied to
the rear wheels.

1 horsepower is the energy required to lift 550lbs one foot in one
second.

 

The torque figure is what is pushing the car down the street.
Horsepower is roughly an equation of torque over time .

 

Torque is the twisting force at the end of a 1 ft lever attached to the crank, measured in pounds of force applied at the end of the lever. Thus pounds per foot, lbs/ft.
John

 

but b/c the motor is rotating you can not really take that foot thing
so someone came up with this formula

HP = (torque*rpm)/5252

though that is exluding driver, weight, gearing, aerodynamic, friction and drivetrain loss, and also the power curve

there are times when a car might put out more peak power but b/c it is over such a narrow band that when he shifts it will throw him out of his power range so now he is moving a lot slower
this should fall under your "everything setup right" though

 

Yea, what rx7speed said.

 

This is probably the best way I've ever heard it put.....
Horsepower is how FAST you hit the wall,
Torque is how HARD you hit it! :rockon: :rockon:

 

my dad used to race formula one cars in the 70's and he said that for street cars the car with the most torque will win a race hands down on the street. but at the track he said the car with the most hp will win hands down. he said street cars will not use the hp to their full extent but they will use the torque.

 

that is such a over simplification on what will win a race

you can not even come close to saying that

that is why a S2000 which almost NO torque can still run with most 305 tpi cars and prolly even give a 350 a good run

even in a street race

you can't have hp without torque
hp just says when you make the power for the most part
though ask me I would rather make a motor that has power higher up then use some gears to help quite a bit

 

It might sound :rockon: but unfortunately it doens't mean anything.

In a racing sense, torque is useless. You can always make up for low torque with gearing. Conversely, you can have all the torque in the world, but if you don't have any power you're not going anywhere.

-Power is the rate at which you can do work.
-Work is a measure of force applied over time.
-Force over time....hmm, that sounds like drag racing.
-So more power means you can do the same work in less time (or more work in the same time).

Now sure, torque is a factor in power, but it's important to note that the concept of torque does not play into the above example, only power. Just don't forget that average power is what you're talking about in a race. Torque only matters as it relates to power.

A simple example to look at would be my vert. TPI so gobs of low end torque right, but also very heavy. Below 3k rpms i'm a complete slug. Even though i'd bet i make more torque at 2400 rpms than at 5000, there is a very pronounced difference in my rate of acceleration between coming out of the hole and when i'm coming up on the 1-2 shift. Gear reduction is the same. Hell, the converters STR is even helping out at 2400. Yet still, i'm pulling harder at 5k than at 2.4k. Why? Simple. Power. At 2400 i'm not making any power. At 5k, even though torque is falling off, it still is making some power, at least more than at 2400. Because i am making some power i am still accelerating.

edit, thought i'd add rough numbers to illustrate for the physics impaired:

Let's say
300lbft @ 2400. (300*2400)/5252 = 137hp
200lbft @ 5000 (200*5000)/5252 = 190hp

That's why it's all about the POWER band, not the TORQUE band. You can feel the difference in acceleration even though i'm making LESS torque at 5000 rpms. Thats also why my weenie little LB9 can run with most of the stockish L98s here even though if you drove in it you'd think it was a yugo. I do make the power, even if i do have the torque to weight characteristics of a minivan out of the hole.

re: more power always wins...
Properly set-up the car with more power always wins. Of course this is an ideal physics experiment. Even a car w/ just a good peak HP number wins here cuz i can assume a perfect CVT (continuously variable transmission) to always keep it on the power peak Or i could have meant more average power and it would work with normal gearboxes.

 

Just when you think ya know everything, someone will come
along and relearn ya.

I never looked at it that way but sure makes a lot of sense now
why my car pulls alot harder in the upper rpm's .

 

Power=Work / Time

Or:

Power = (Force x Distance) / Time

Work=Force x Distance
When talking about torque: Work=Force x Lever Arm

I think you were just thinking faster than you were typing. You got power right, but if you had just put "Work is a measure of force applied over distance" and put "Work over time....hmm, that sounds like drag racing" you'd have it all right.

 

OMG you're right. Actually i worked it out on paper even to make sure i was thinking right. I swear my notes said something like:

P = W/T

W = FD = (ma)d

P = mad/T

a = PT/md

or something like that, integrated over time, x=, etc, etc, lol

so yeah i was typing w/o paying attention

 

I always tried to use this analogy when understanding torque and horsepower. Whether its correct or not, is up to you, but I feel its as correct as I could get it without thowing numbers around.
>We all know football right? Of course, well hopefully we do. Well lets say you're at practice and you're hitting the dummy pads right. Now you usually get in a stance a couple feet in front of it, and then WAM hit it, and push. Not just hitting it, you want to move it.
>Your muscles in this analogy are Horsepower.
>The distance from the pads are considered your Stall Speed.
>The tensing of your muscles are the Torque.
>And the pad can be considered the Car.
>And umm.. your breathing can be considered the back pressure... LOL Rx7Speed, jus kidding.

Aight, now use the above terms, excluding the last one hehe, jus jokin. Now in a High Horsepower, Low Torque situation, this is what would happen. Your muscles are very strong enough to push this pad. However you would not tense up muscles (no torque) that much, to not at all. And your distance (stall speed low) is close to the pad. Now you goto hit the pad, and what happens? Hardly nothing, you might move the pad a little, but don't you need a lot more torque to get that thing moving? OF COURSE! Sure you have a good amount of Horsepower, but right now you have fight off inertia, to be able to unleash it. So after straining to get it moving, you might be able to start moving it, but hey isn't there and easier way? Yup!
In this situation you would either A) Need to achieve more torque some how, by tensing up muscles. B) Or at the very least get a higher stall, give your self some distance, so there will be some torque being transfered, a little leverage.

Now in a High Torque, Low Horsepower situation. You are scrawny, hardly no muscle mass. You would tense up your muscles tight. Even give your self some distance, stall speed, to utilize the torque optimally. Now you go to hit it, and WAM you hit it hard. It might even move it a little, but remember you're not that strong (no horsepower), so now the torque atleast got you to hit it hard, however, you don't have much horsepower to keep it moving. What do you need to do? Gain more horsepower, hit the gym.. hehe.

And in a Low Torque, Low Horsepower situation. Stall speed doesn't matter here, cuz you don't have enough power or torque to take advantage of it realisticly. So practicly in this scenario you're just leaning on the pads. Just like those civic ricers, theyre leaning on those pads, going no where. What do you need to do? Well hmm maybe get some stickers, some appearance mods, cuz I mean hell if the car aint moving fast, that means I can see it too well, might as well make it look good.
..While for our cars, theres no purpose to appearance mods, I mean all they can see is a blur, so whats it matter, hehe.

I really hope this helps out, even if my words don't make sense, try to use this analogy, like the terms above. See if you can try to make more sense out of it if you need to. I like to think of Torque as the Clutch pedal. And Horsepower as the gas pedal. See what ya can do with that idea. The clutch is used, then its slowly let out, then the gas pedal takes over. Just like how torque is used, then its slowly let out, then horsepower takes over.
Peace...