Torque and Horsepower?

Question

Can someone please tell me in detail what is torque and what is horsepower? Also how can an engine produce more torque in the pistons at a lower rpm than high rpm? How is torque tested? How is horsepower the most at 7,000 rpm rather than maximum? Wouldn't the engine be able to handle more at a higher rpm? Basically i jus want a detailed explanation of torque and horsepower and how then engine produces more torque at lower rpm and higher horsepower not at the redline?

Answer 1

Roughly speaking, horsepower is what makes your rpm needle go UP the gauge when you step on it, it is the accelerant.
Torque is what manages to keep the rpm needle steady regardless of load, it is the stamina, the staying power.

One can manufacture an engine any which way, tune it for horses or tune it for torque... Oddly enough one can not have one without the other, but one can have more of one than the other.

In a race, an engine with more horses than torque would benefit from a closed transmission, while an engine with more torque would benefit from wider spaced gears, this changes in trucks that sport both high ends of torque AND closed transmission, mostly for superior PULL power.

Take two cars, equip one with more horses than torque, tune the other with more torque than horses, and set them up to race:
When unloaded, the car with more horses wins, hands down.
Start adding weight, put a thousand pound trailer on each car, and the torque based engine continues to plod along, torque is not phased by load, horses are.
Eventually, with enough of a load, the horsepower-based engine won't move the car, while if the other car has enough torque it will still move, if slowly.

However, in the ultimate competition between torque and horsepower, if modifications are no issue then in the end horses always win.

As a rule, only vehicles that have to deal with severe loads will be tuned or geared for torque (like trucks) so they can maintain speed going uphill, for instance. Obviously, torque sacrifices acceleration, while horses sacrifice stamina.

As for when or where an engine produces its max output, all engines have a power curve that peaks at a certain rpm, it is also part of the tune but as a rule the peak is around 4-5000 rpm, we allow it to go further but it is best to shift gears before the line drops too far... This peak and curve can be controlled or tuned, some cars have variable timing camshafts, and some cars DO peak later than others, the bmw is one of a kind that does not lose power all the way to the redline, thou it only starts to gain power at 3000 rpm, hence the curve only covers 3-4000 rpm's or so.

Hope that made sense, it's rather basic.

Answer 2

Torque is part of the basic specification of an engine: the power output of an engine is expressed as its torque multiplied by its rotational speed. Internal-combustion engines produce useful torque only over a limited range of rotational speeds (typically from around 1,000–6,000 rpm for a small car). The varying torque output over that range can be measured with a dynamometer, and shown as a torque curve. The peak of that torque curve usually occurs somewhat below the overall power peak. The torque peak cannot, by definition, appear at higher rpm than the power peak.

Understanding the relationship between torque, power and engine speed is vital in automotive engineering, concerned as it is with transmitting power from the engine through the drive train to the wheels. Typically power is a function of torque and engine speed. The gearing of the drive train must be chosen appropriately to make the most of the motor's torque characteristics


http://en.wikipedia.org/wiki/torque...
This explains it pretty good. Click the shortcut.

Answer 3

torque is the twisting force that an engine will develop, horse power is the measured amount of work an engine can do. there is a mathematical equation that uses one to calculate the other but i dont have it right now. either is usualy measured with a dynomometer.

Answer 4

torque is when your trying to pull something---horsepower is the size of your engine