As you may have already read, horsepower is just a function of torque and engine speed.
First some definitions:
Horsepower is the rating that describes how powerful an engine is.
Torque can be described as how flexible or how much force can be expressed in a given gear.
How fast the car accelerates, its top speed, how fast it “feels” are all results of the tuning of other components of the car – such as transmission, suspension, programming, etc.
What many people neglect to notice is that horsepower and torque figures are almost always expressed at a certain engine speed.
For example, you may read:
130 hp @ 3,400 RPM
109 ft-lb @ 2,800 RPM
For most drivers, a car will feel more responsive and generally “faster” when the RPM requirements are low. Because most divers do not like to have their engine racing along at 6,000 RPM.
Compare this to a Honda S2000:
237 hp @ 8,300 RPM
153 ft-lb @ 7,500 RPM
What you may or may not know is that most cars can’t even run their engines this fast.
The S2000 is has a considerable amount of power available for the size of the car, but in order to access it, the driver needs to get into the accelerator and get the engine really spinning. This is not how many drivers want to experience driving and will result in the driver experiencing less than the peak capabilities of the car. This probably had some effect on the poor sales of the car.
How does this get back to your original question?
The peak numbers only tell a part of the story. But generally, the higher the HP, the more powerful the car is: more power typically = faster overall acceleration, higher maximum speeds, higher weight limits/towing capacities, etc.
Higher torque numbers result in: better in-gear acceleration (useful for passing or getting the car under way), lower engine speed at a given load (towing a trailer up-hill in an Accord and a F-150 may be possible for both, but the gearing and torque of the Accord will make it sound the engine is racing all the way up).
I should mention that one of the downsides of high torque is when there is limited traction. In a muddy ground, gravel, or wet pavements, high torque can make it easier to spin out. This could impact your ability to get moving from a stop, to making the vehicle more prone to losing control when in motion.
N.B The Formula: Horsepower = Torque x RPM / 5252
(5252 is just a conversion factor depending on what units you are using. Sometimes people use 5250.)
SOURCE: quora.com