Hp vs. Torque

[kko]

Horsepower versus torque,
Wich one is Better to have on a race track and drag strip , what would be better to have more of in what situation, How much is too much?
I know that this is kind of broad but give it a shot.

ex comming out of a turn, of the line, what having one but little of the other would mean.

[KnifeEdge_2K1]

torque is a measure of force, horse power is ... a measure of power
torque is the force which turns the wheel, force usually only has one direction but since this is a wheel its more of a "twisting" force (forgive my bad vocab)

power is a measure of how quickly work can be done, and work is displacement times force, but the displacement vector must be the same as the force ... wow starwars flashback ...

neways power is usually only relevent in the top end of the rev range, remember how i said work = displacement * force
well in an engine the displacement is always the same (the stroke), and unless you have some sort of variable crankshaft i dont know how this can be changed

the force is the torque so the engine is actually doing less work at the high end of the rev range then at the lower end (the torque curve drops off i believe because the air cant get into the cylinders as quick since the valves are open for shorter amount of time)

neways power is a measure of how quickly work is done, although the engine is doing less work per stroke at 7000rpm then say 3500rpm its moving twice as fast

the equation for horsepower is torque*rpm/5252
this is why the horsepower is always = to torque (in lb-ft) at 5252rpm
this is also why power is always less then torque (in lb-ft) at any rev below 5252 and always more then torque at above 5252

[Sweeney921]

one wont work without the other

[KnifeEdge_2K1]

p.s i hvnt done physics in a long time so maybe one of you can correct me on my mistakes

[kko]

great now can any one answer my question?
sry if that sounded rude

[motorhead]

basically torque is the pulling power of the vehicle. How much weight the engine of the vehicle can pull in any specific gear. Horsepower is actually the outright amount of force the car can exert on opposite forces relative to weight. You are right in saying each will not work without the other.

[Hell_Unleashed]

torque is a measure of force, horse power is ... a measure of power
torque is the force which turns the wheel, force usually only has one direction but since this is a wheel its more of a "twisting" force (forgive my bad vocab)

power is a measure of how quickly work can be done, and work is displacement times force, but the displacement vector must be the same as the force ... wow starwars flashback ...

neways power is usually only relevent in the top end of the rev range, remember how i said work = displacement * force
well in an engine the displacement is always the same (the stroke), and unless you have some sort of variable crankshaft i dont know how this can be changed

the force is the torque so the engine is actually doing less work at the high end of the rev range then at the lower end (the torque curve drops off i believe because the air cant get into the cylinders as quick since the valves are open for shorter amount of time)

neways power is a measure of how quickly work is done, although the engine is doing less work per stroke at 7000rpm then say 3500rpm its moving twice as fast

the equation for horsepower is torque*rpm/5252
this is why the horsepower is always = to torque (in lb-ft) at 5252rpm
this is also why power is always less then torque (in lb-ft) at any rev below 5252 and always more then torque at above 5252

Wow... I worship you

[Benz_Boy_1]

me too

[Ferrari Tifosi]

Knife did answer you question KKO, not directly but enough so you could put two and two together.

Anyways for coming out of turn torque is valuable because you'll be low in the rev range. Same with off the line on a drag run, need torque to mobilize things. In a F1 look at it, tracks like Monaco (tight, twisty track with many slow sections) a more torquey engine is more beneficial that a high hp engine, this could be seen with Renault this year. On the opposite side, a track like Monza requires a higher hp engine setup because of the long straights and fast sections. In the end both are great to have and with a proper design of an engine a great power and torque curve can be attained, to give you the best of both worlds.

[kko]

I under stood What Knife said, but i just wanted someone to simplify it, (to tired to think)
thanks too both of you.

[Renesis]

hmmm....

hp= (torque x rpm)/5252

[Alastor]

I under stood What Knife said, but i just wanted someone to simplify it, (to tired to think)
thanks too both of you.

It is hard to explain the difference between power (horsepower or watts) and torque without using mathematics. But as KnifeEdge_2K1 explained using physics basically work and power are related. Work has to with “how much”, and power refers to “how quickly”.

In terms of the internal combustion engine the amount of work and power that the engine produces changes with engine speed (RPM). So at some RPM the engine will be able to do more work than at any other RPM, this corresponds to the peak torque. Also at some RPM the engine will produce the most power (work per unit time), and this is referred to the peak power.

In terms of automobile performance the peaks are less important than actual profiles of the power or torque curves. This is because the automobile engine has to operate over a variety of engine speeds. The more area under either curve will provide better overall performance.

Although it is interesting to note for a vehicle with a fixed gear transmission maximum acceleration occurs at the peak torque. However, maximum acceleration for any given speed will occur at peak power.

So what does it all mean? Well a fast car should have both lots of power and torque. In other words it should be able to perform a lot work and it should be able to work quickly. Also, the power and torque should be available across the largest engine speed possible.

[fpv_gtho]

Power, be it HP or kW is a measure of energy transfer pretty much. Energy is rated in joules, and 1 joule of energy transfered in 1 second is 1 watt.

Torque is the twisting force of the engine, it moves the weight of the car basically. A heavier car will need more torque than a lighter car to move.

[Alastor]

Power, be it HP or kW is a measure of energy transfer pretty much. Energy is rated in joules, and 1 joule of energy transfered in 1 second is 1 watt.

Torque is the twisting force of the engine, it moves the weight of the car basically. A heavier car will need more torque than a lighter car to move.

Actually if you look at the units torque would be a measure of "energy transfer". Torque has the same units of work (force * distance), and work can be measured in joules (J). As you stated above energy is also measured in joules. The J/s is an equivalent unit of power, so power is a measure of "energy per unit time".

[fpv_gtho]

perhaps "energy conversion" wouldve been a better way to put it...the rate the chemical energy in the fuel is converted to kinetic energy on the crankshaft