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More Horse or torque?

  • Horse Power wins!

    Votes: 15 31.3%
  • Torque wins!

    Votes: 19 39.6%
  • 135mph in a spider is possible:eek:

    Votes: 14 29.2%

  • Total voters
    48
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Discussion Starter #1 (Edited)
Might as well make a thread dedicated just to it!
Torque Multiplication: The gaining of torque by use of gears, belts and/or pulleys.
Horsepower Multiplication: Power of a point (relative to a given curve), the result of substituting the coordinates of any point in that expression which being put equal to zero forms the equation of the curve; as, x^2 _ y^2 - 100 is the power of the point x, y, relative to the circle x^2 _ y^2 - 100 = 0.
Add them together: Maximum acceleration at any speed occurs at the HP peak.
Maximum acceleration in any gear occurs at the torque peak.
Oh, ya, I know, confusing, lets break this down a bit:
A while back, a gentleman by the name of Watt made some observations, and concluded that the average horse of the time could lift a 550 pound weight one foot in one second, thereby performing work at the rate of 550 foot pounds per second, or 33,000 foot pounds per minute, for an eight hour shift, more or less. He then published those observations, and stated that 33,000 foot pounds per minute of work was equivalent to the power of one horse, or, one horsepower.
For purposes of this discussion, we need to measure units of force from rotating masses (crankshafts), so we'll use terms which define a *twisting* force, such as foot pounds of torque. A foot pound of torque is the twisting force necessary to support a one pound weight on a weightless horizontal bar, one foot from the fulcrum (pivot point).
Now, it's important to understand that nobody on the planet ever actually measures horsepower from a running engine. What we actually measure (on a dynamometer) is torque, expressed in foot pounds (in the U.S.), and then we *calculate* actual horsepower by converting the twisting force of torque into the work units of horsepower. That is what is meant by SAE CORRECTED HP!
OK. Remember Watt? He said that 33,000 foot pounds of work per minute was equivalent to one horsepower. If we divide the 6.2832 foot pounds of work we've done per revolution of that weight into 33,000 foot pounds, we come up with the fact that one foot pound of torque at 5252 rpm is equal to 33,000 foot pounds per minute of work, and is the equivalent of one horsepower. If we only move that weight at the rate of 2626 rpm, it's the equivalent of 1/2 horsepower (16,500 foot pounds per minute), and so on. Therefore, the following formula applies for calculating horsepower from a torque measurement:

Torque * RPM
Horsepower = ------------
5252

This is not a debatable item. It's the way it's done. Period.
Now, what does all this mean in carland?

First of all, from a driver's perspective, torque, to use the vernacular, RULES :). Any given car, in any given gear, will accelerate at a rate that *exactly* matches its torque curve (allowing for increased air and rolling resistance as speeds climb). Another way of saying this is that a car will accelerate hardest at its torque peak in any given gear, and will not accelerate as hard below that peak, or above it. Torque is the only thing that a driver feels, and horsepower is just sort of an esoteric measurement in that context. 300 foot pounds of torque will accelerate you just as hard at 2000 rpm as it would if you were making that torque at 4000 rpm in the same gear, yet, per the formula, the horsepower would be *double* at 4000 rpm. Therefore, horsepower isn't particularly meaningful from a driver's perspective, and the two numbers only get friendly at 5252 rpm, where horsepower and torque always come out the same.

In contrast to a torque curve (and the matching pushback into your seat), horsepower rises rapidly with rpm, especially when torque values are also climbing. Horsepower will continue to climb, however, until well past the torque peak, and will continue to rise as engine speed climbs, until the torque curve really begins to plummet, faster than engine rpm is rising. However, as I said, horsepower has nothing to do with what a driver *feels*.

You don't believe all this?

Fine. Take your non turbo car (turbo lag muddles the results) to its torque peak in first gear, and punch it. Notice the belt in the back? Now take it to the power peak, and punch it. Notice that the belt in the back is a bit weaker? Fine. Can we go on, now? :) 3 things that win every race: Torque. Cubic Inches. Traction....
 

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3 things that win every race: Torque. Cubic Inches. Traction....
In most race series engine size is set, or atleast the max size is, thus this basically specs out the torque figure.

Thus in this case the engine that can produce more power wins (as remember the torque is the same). Usually this is done by making a stronger engine that can rev higher. With this advantage they can play more with the gear ratios and thanks to gear ratios improve their acceleration (thanks as you say to torque multiplication). This is why race cars are so obsessed with power ... if the class was open, as you say torque wins, think CanAm and 8 litre v8's.

In the end it is this simple:
Torque in each gear dictates acceleration.
Power in each gear distates top speed.

Pete
 

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Horsepower = work.

The area under the horsepower graph is what makes it move, torque is nothing without revs. You can have 5000Nm on the crank but if it doesn't turn over the car doesn't accelerate. Pretty simple.

Your little example with "gunning it at peak" is not valid because normally you will have a lot of other factors involved at the higher revs/speed, air resistance for instance which raise by the square of the speed increase...

It does not matter what anybody thinks, it's not something someone can change with arguments. It's like arguing that earth gravity is less when you're swimming because you feel lighter. ;)
 

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I'm writing this r e a l slow so that DD can get it.

Force is force and it does not move.

When it moves in space and time it does work, which is measured in units of power--the most popular is HP.

Torque is a turning moment of a static force--no movement.

When this force moves it does work which can be calculated in the usual units of power.

End of story.
 

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Why did I ever waste all those years and $$$ on college and an advanced science degree? Now, if only someone wold explain mass versus density, or volts versus amps . . .

Someone else, that is.
 

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Perhaps member Does135 would care to comment ?
Funny aside - I was taking care of a patient the other night, and I got him talking about cars while I was working on him, to relax/distract him. As it turns out, back in the 70's he had an Austin-Healey 3000 that went 172 mph, across one of the local causeways from Tampa to St. Pete. Of course, he was pretty heavily sedated at the time, so at least he had an excuse.
 

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Why does it matter? Horsepower is measured in cubic $$$$ PERIOD...
I don't care what you build if I throw enough money at it I'll out run you.
Since I'm over the age of 18 I don't have anything to prove to anyone, so I'm outta here
 

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Why did I ever waste all those years and $$$ on college and an advanced science degree? Now, if only someone wold explain mass versus density, or volts versus amps . . .

Someone else, that is.
Dean

Don't get anyone going on the difference between mass and weight.:eek:
 

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Discussion Starter #13
With this advantage they can play more with the gear ratios and thanks to gear ratios improve their acceleration
Torque in each gear dictates acceleration.

Pete
Exactly my point! Acceleration is still gaining mph, true or false? You can't be accelerating if your speed isn't increasing, so that is the importance of torque to begin with. Changing gears is the other thing, numerically lower gears will allow for higher top speeds if you have the torque to spin those gears...coming together now?
 

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Discussion Starter #15
Horsepower = work.

Your little example with "gunning it at peak" is not valid because normally you will have a lot of other factors involved at the higher revs/speed, air resistance for instance which raise by the square of the speed increase...
Ah, but even with what you say: Horsepower=work, then if you don't feel the kick at your Max HP RPM in say 5th gear, what exactly does that tell you?? Work is work, rolling resistance, aerodynamics effect it, but work is still work, either you have it or you don't. You know you'll feel it at max torque rpm:rolleyes:
 

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Discussion Starter #17
I'm writing this r e a l slow so that DD can get it.

Force is force and it does not move.

When it moves in space and time it does work, which is measured in units of power--the most popular is HP.

Torque is a turning moment of a static force--no movement.

When this force moves it does work which can be calculated in the usual units of power.

End of story.
You still don't get it which is fine, some do get it. HP is derived from torque, I don't care what you are running or how high your RPMs get. Dynometers measure torque and then calculate (SAE corrected) the HP for different RPMs. You almost had it when you said "When it moves in space and time it does work, which is measured in units of power--the most popular is HP." but then you had a brain fart or something and didn't read or didn't understand the origins of this thread.
 

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I'm real tired of this discussion - already.
Speaking of tires - now what do you guys use to get that horsePOWER or torquePOWER to the ground?
Maybe a healthy discussion of tire brands/sizes/models/specifications/inflation will overPOWER this thread:D

ps - This is a Spider forum isn't it? If we're going to talk POWER maybe we should include other bbers?
 

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Discussion Starter #20
I'm real tired of this discussion - already.
Speaking of tires - now what do you guys use to get that horsePOWER or torquePOWER to the ground?
Maybe a healthy discussion of tire brands/sizes/models/specifications/inflation will overPOWER this thread:D

ps - This is a Spider forum isn't it? If we're going to talk POWER maybe we should include other bbers?
#1 Don't hi jack this thread!:mad:
#2 Any BBer is welcome to this thread as long as it stays on topic, no more train wrecks and no more disrespecting other members!
 
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