Torque....what the hell is it?

[trim007]

Please could someone tell me the difference between BHP and torque, and what does torque actually mean in car tems. why do diesels have a high torque to BHP ratio.?

Many Thanks

Trimmy

[Toureman]

In simple terms,

BHP is the measurement of power an engine produces at maximum revs.

Torque is a measurement of power throughout the rev range of an engine.

A vehicle with high BHP and low torque has to be driven with max revs to accelarate quickly, A vehicle with high torque will accelarate throughout the rev range making it easier to drive.

[Clanad]

Although I agree with Toureman in general, a more specific definition of Torque could help understand his/her explanation. Simply put, horsepower is a linear measurement, i.e., how much force is applied along a line in the direction the object being moved, whereas torque is a measurement of force applied in a rotational manner, such as an internal combustion engine, which, of course rotates as it produces power. It's usually defined in foot/pounds for measuring purposes. It does require a consideration of RPM as well, as previously explained, and the resultant is a combination of both... Additionally, using a dynamometer, horsepower is a calculated value by measuring the torque.. The dynamometer measures torque and rpm and then from these calculates horsepower.

[Toureman]

Good explanation Clanad, I am a his.

[Melliexr]

In really simple terms:-
Torque is what gives a 1970's 8-litre Cadillac the power to pull tree stumps out of the ground on tickover.
BHP is what gives Schumacher the ability to tear round a racetrack so long as he keeps the rev counter up near the red-line.

[Andyvon]

Even more simply -
BHP (brake horse power) is a measure of the power that an engine can deliver to the wheels. The more BHP the faster the car can go.
The 'torque' is a measure of the 'twisting' ability of the engine to turn the flywheel which then turns the clutch and wheels. It comes more into play when accelerating. The more torque your engine has the quicker you can accelerate.

[trim007]

Answeres you have been brilliant in your answers. However Andyvon (or anyone else)for the purposes of clarifing a query in the office how can a BMW 330d have more torque than an M3 but a not accelerate as quick?


Many thanks in advance

[tali122]

330d has more torque because inhererntly diesels have more "pulling power" than a petrol car (a fiat 2.4td has more torque than a ferrari 308) , now an m3 will accelerate quicker 0-60 , but "thru the gears" ie 30-50 mph or 50-70 mph in 3rd /4th .5th gear the 330d the acceleration times will be a lot closer

[Andyvon]

Hi trim007!

I was trying to keep it simple. Its a hell of a tough question to answer simply though.

[Jay70]

The best way to imagine the difference itsto think of a hammer being used. BHP is equivalent to the speed the hammer is being swung and torque is equivalent to the weight of the hammer head. I told a guy at work about the BMW 535d having nearly as much torque as the new V10 M5 and he wouldn't have it even though it's quoted in Top gear magazine. But then he is an IT engineer.

[trim007]

your right Andyvon. I reckon i have the answer no

Thanks for the advice and help:)

[trim007]

your right Andyvon. I reckon i have the answer now thanks to all the answerers!

Thanks for the advice and help:)