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What is the difference between Power ( BHP ) & Torque in technical & laymens terms for Cars? What is the significanse of The same at given RPM , i.e. Whether the same at lower RPM is better or higher RPM ?
By Deepam Morparia 10 October 2009

power is the critical determining factor for maximum acceleration, and torque is necessary for driveability.
An engine with high torque throughout the RPM range will have good low-RPM and part throttle response.
Power is important rather than torque at the engine which in modified by the gearing (gearing is torque multiplier) not power multiplier
It is therefore clear that in order to maximise your acceleration, it is very important to have high power, rather than high torque.

Answer by Ali 10 October 2009

well, The usual way of understanding this is ... Diesel engines had more torque than a petrol engine.. so diesels accelerate slower than petrol even though they have high torque. Good torque helps in pulling power, like a safari can pull 8 ppl easily and the same safari with petrol engine cannot pull 8 ppl as easily as a diesel, but it can accelerate faster due to power !!

Answer by Krishna 10 October 2009

See, Torque is the amount of force produced at the end of the crankshaft whic stands connected to the gearbox. In common words, torque is pulling power. The torquier your vehicle is, the more weight it can effortlessly pull. Torque is dependant on two major points

1- The Size of the bore
2- The Higher air/fuel mixture (Lean Mixture)

Take for example, a door. Try opening a door by pushing the handle. Its fairly easy to do so. Now try pushing the door from near the hinges, its harder right? Mark me, its torquier. Get it? It is a lil' difficult to explain in words.!

Coming to Bhp which stretches to Brake Horse Power. Its a measure of how quickly your vehicle (specifically the engine) accelerate. Its basically a rate measure and shows how quickly your engine can attain speed.

Coming to RPM. If you're vehicle produces higher torque at lower engine speed, then :

1- You're gonna get more mileage :)
2- You're gonna be able to enjoy in city drives as there will be minimum gear changing.
3- You ccan quite easily overtake the other vehicle on road.

If you're vehicle produces higher torque at higher engine speed, then :

1 - You'll get bad mileage!
2- But hey, its a race bred engine, you can beat the hell outta your opponents in any racing form :)

Wish it helped :)

Answer by Siddharth 10 October 2009
Expert`s comment:

BHP is the break horse power available at end of crank shaft.
BHP= IHP-FHP ie Indicated horse power minus frictional power. BHP is the total actual power developed at end of crankshaft at given RPM . RPM indicates to the rotations per minute at end of crankshaft.Torque is the twisting effort that is develped at end of crankshaft at given RPM expressed in Newton Meter.More torque in lesser rpm indicates better utilisation of power.The Torque developed in an engine depends upon the constructional features and design parameters, generally diesel engines are more heavier and power to weight ratio is more resulting in better torque.The terms can best be explained in terms of technical formulae than the general terms. As the gears are engaged to lower gears.The total torque available will be more than that available at higher gears due to design of gears depending upon design considerations including number of teeth.The total torque available at end of wheels depend upon gear ratio of transmission as well as the differential which will be constant for a given vehicle.

Answer by Shiva Shankar 10 October 2009

u shouldnt compare Disel and Petrol on the same platform as Petrol engines Run ar Higher RPM and Diesel comaparitively Lower ,,so when u make use of the Gear system the Extra Torque produced at the Crank shaft in Diesel engine is offset by the gear Ratios so a Petrol engine Get a Higher 'Pickup",, compared to a disel engine.

Answer by Vij 10 October 2009

in short
bhp is total power dat an engine can generate @ rate of given rpm,for eg
78@7500rpm & 78@6600
in dis 2nd option is better coz it generates same power at lower rpm dat leads mor acceleration,less wear n tear,n a guuud engine

Answer by Amit 10 October 2009
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