What does horsepower determine?

[Fox5]

For instance, say my car is 1500 pounds, and has 142 horsepower, what exactly does that mean? Can the horsepower be used to determine the maximum speed, or what?

 

[Safeway]

It's a measure of output. Google it. Wikipedia it.

 

[suicidalpigeon]

wow with that weight that car should count as a lotus elise

 

[everman]

Torque and aerodynamics are also important factors, not to mention hauling around sumo wrestlers which will also kill top speed and acceleration.

 

[Kalvin00]

 

[b0mbrman]

Originally posted by: everman
Torque and aerodynamics are also important factors, not to mention hauling around sumo wrestlers which will also kill top speed and acceleration.

Don't forget your ratios...

 

[ElFenix]

horsepower is nothing more than torque at a high rpm. it means you don't have to shift as much.

the manufacturers put emphasis on hp because power figures aren't changed by the lever action of a transmission, while torque, as a type of force, is. so, each time you change gears your torque at the wheels is changing, but your horsepower isn't. which is why you accelerate harder in first gear than any other.

 

[QuitBanningMe]

WTF car do you have that is 1500 ponds?

I have a "light" car and it is 2600 pounds.

 

[suicidalpigeon]

500lb gokart with a honda civic engine= :thumbsup:

 

[quakefiend420]

Originally posted by: QuitBanningMe
WTF car do you have that is 1500 ponds?

i think its just a hypothetical situation

 

[QuitBanningMe]

Originally posted by: quakefiend420

Originally posted by: QuitBanningMe
WTF car do you have that is 1500 ponds?

i think its just a hypothetical situation

ahhhh...my reading comprehension is lacking....sorry

 

[Pacfanweb]

Originally posted by: Fox5
For instance, say my car is 1500 pounds, and has 142 horsepower, what exactly does that mean? Can the horsepower be used to determine the maximum speed, or what?

Yes, there are calculations that can tell you how fast any particular combination of power/weight/gearing/aerodynamics can go.

There are also calculations that can predict your 1/4 mile time and speed if you know your HP and weight, too. These also are affected by gearing, and traction.

Anyway, HP is a result of a dyno test that measures torque, and the dyno uses a calculation to figure the HP.
They are inseperable. To have HP, you must have torque. The more torque you have at a higher RPM, the more HP you will have. They are not independently obtainable.

 

[Injury]

So, in layman's terms, would you guys say that horsepower is a measurement of the force at which a car is propelled foward?

And if horsepower is a constant, then the scope of its power is directly related the weight it must push?

Does a car deliver the same horsepower no matter how far in a person pushes the gas pedal?

yeah yeah, I'm a bit of a car n00b, but cars are one of the things I'd love to know much much more about than what gran turismo can teach

 

[Pacfanweb]

Originally posted by: Injury
So, in layman's terms, would you guys say that horsepower is a measurement of the force at which a car is propelled foward?
No, HP is a measurement derived from torque, which is basically what you described.

And if horsepower is a constant, then the scope of its power is directly related the weight it must push?
No, the power is the same, the weight determines how quick/fast you can go with that amount of HP. So do other factors, like traction and aerodynamics. Most passenger cars would not be able, if they didn't have rev limiters, to reach max. rpm in high gear...the wind resistance would be too great for their engines to turn up in high gear.

Does a car deliver the same horsepower no matter how far in a person pushes the gas pedal?
No. Max HP is only obtained at WOT. (wide open throttle)

yeah yeah, I'm a bit of a car n00b, but cars are one of the things I'd love to know much much more about than what gran turismo can teach

Google is your friend.

 

[TomKazansky]

Originally posted by: ElFenix
horsepower is nothing more than torque at a high rpm. it means you don't have to shift as much.

the manufacturers put emphasis on hp because power figures aren't changed by the lever action of a transmission, while torque, as a type of force, is. so, each time you change gears your torque at the wheels is changing, but your horsepower isn't. which is why you accelerate harder in first gear than any other.

actually, hp = torque x rpm / 5252, which means when u rev ur engine hp does rise up. Why would racecar drives redline their car if they don't need peak hp?

hp + gearing matters more on a racecar. Torque makes everything run; excessive torque makes everythign smooth. However on turns torque sometimes can help a car accelerate out of a corner a lot faster than a car with little torque.

 

[Pacfanweb]

Originally posted by: infestedgh0st

Originally posted by: ElFenix
horsepower is nothing more than torque at a high rpm. it means you don't have to shift as much.

the manufacturers put emphasis on hp because power figures aren't changed by the lever action of a transmission, while torque, as a type of force, is. so, each time you change gears your torque at the wheels is changing, but your horsepower isn't. which is why you accelerate harder in first gear than any other.

actually, hp = torque x rpm / 5252, which means when u rev ur engine hp does change.

hp + gearing matters more on a racecar. Torque makes everything run; excessive torque makes everythign smooth.

Wrong. Once again, HP and Torque are NOT mutually exclusive. Gearing and weight matters to every single vehicle made.
You can't have HP without torque.

 

[TomKazansky]

Originally posted by: Pacfanweb

Originally posted by: infestedgh0st

Originally posted by: ElFenix
horsepower is nothing more than torque at a high rpm. it means you don't have to shift as much.

the manufacturers put emphasis on hp because power figures aren't changed by the lever action of a transmission, while torque, as a type of force, is. so, each time you change gears your torque at the wheels is changing, but your horsepower isn't. which is why you accelerate harder in first gear than any other.

actually, hp = torque x rpm / 5252, which means when u rev ur engine hp does change.

hp + gearing matters more on a racecar. Torque makes everything run; excessive torque makes everythign smooth.

Wrong. Once again, HP and Torque are NOT mutually exclusive. Gearing and weight matters to every single vehicle made.
You can't have HP without torque.

obviously, the equation shows that they are NOT mutually exlusive. If torque = 0 then u can't have hp. hp is the measurement of how much work can be done with the torque from the engine at this rpm. Basically the higher you rev, the more hp u get. Torque however has its own torque curve.

 

[imported_Phil]

Oooh, it's a few days ago again! Spooky.

 

[Murphy Durphy]

Horsepower is the amount of raw power output times the power of a single horse.

1HP = the power of 1 horse.
500HP = a lot of horses.

You geeks are thinking too hard! Torque, friction, meh. It's horses damnit.

 

[TomKazansky]

Originally posted by: HajikuFlip
Horsepower is the amount of raw power output times the power of a single horse.

1HP = the power of 1 horse.
500HP = a lot of horses.

QFT

 

[Forsythe]

745,6999 W or J/s, that's the equivalent of a horsepower, it's an older measurement still used.

 

[Forsythe]

Originally posted by: infestedgh0st

Originally posted by: HajikuFlip
Horsepower is the amount of raw power output times the power of a single horse.

1HP = the power of 1 horse.
500HP = a lot of horses.

QFT

And no, even though it would seem so, it doesn't have any relation to actual horsepowers, the two numbers can't be compared.

 

[Pacfanweb]

Originally posted by: Forsythe

Originally posted by: infestedgh0st

Originally posted by: HajikuFlip
Horsepower is the amount of raw power output times the power of a single horse.

1HP = the power of 1 horse.
500HP = a lot of horses.

QFT

And no, even though it would seem so, it doesn't have any relation to actual horsepowers, the two numbers can't be compared.

Wrong, the term "horsepower" was most certainly derived from making calculations of power based on how much work one horse (mine pony, actually) could do.
It's evolved from there quite a bit, but an actual horse is where the calculations came from.

 

[Viperoni]

Originally posted by: ElFenix
horsepower is nothing more than torque at a high rpm. it means you don't have to shift as much.

the manufacturers put emphasis on hp because power figures aren't changed by the lever action of a transmission, while torque, as a type of force, is. so, each time you change gears your torque at the wheels is changing, but your horsepower isn't. which is why you accelerate harder in first gear than any other.

/thread

Also it should be added that your cars rate of acceleration is directly proportional to the shape of the torque curve. This is why a car with a torque curve that falls off quickly (IE: engine can't breathe well at higher RPM's) isn't as much fun to drive and isn't as fast as as car that does have the torque up high.

This is because when you accelerate from a stop, you wind 1st from idle to say 6krpm, then you shift into 2nd, but you're accelerating from say 3500rpm to 6k, then you hit 3rd, and you're going from 4k to 6k... and so on.

If you don't have a nice torque curve in that 3500-6000rpm range... then your acceleratino wont be as good as it could.

Thing is, is that even if you open up the upper end, you really dont' feel it much. I gained ~15hp/15ftlb @ ~5200rpm just by swapping a bigger MAF on my car, but I couldn't tell the difference in the seat of my pants. It definetely showed on the dyno and against other cars I raced though

 

[IHateMyJob2004]

Originally posted by: ElFenix
horsepower is nothing more than torque at a high rpm. it means you don't have to shift as much.

the manufacturers put emphasis on hp because power figures aren't changed by the lever action of a transmission, while torque, as a type of force, is. so, each time you change gears your torque at the wheels is changing, but your horsepower isn't. which is why you accelerate harder in first gear than any other.

You are a retarded. Sorry about name calling rules, but this most accurately descirbes this post.