Why do some cars make allot more torque than bhp, why do others have figures about the same and why do some have torque figures less than the bhp.

 

What's best combination and why?

 

also what's the best figure to go by, bhp or torque??

 

Are the different ways to measure torgue or is it all done by Nm?

 

explain away, i'm stupid :D

Elementary Definitions

 

1) Work

 

Is the ‘physical effort’ required to do some thing, such as pulling a Bucket of Water out of a Well. Its measure or ‘Unit’ is ‘foot-pounds’ or ‘kg-meters’. As an example, consider pulling a bucketful of water weighing 15 Kgs from a depth of, say, 10 Meters. So the ‘work’ done is 15 x 10 = 150 ‘kg-meters’.

 

2) Power

 

It’s the ‘Rate’ of doing ‘Work’, such as pulling 10 buckets as above in one hour or a part of it.

 

The most popular unit of Power is the ‘Horse Power’, which from ancient times was the rate of work an ‘average horse’ could do. In scientific parlance today, it translates into 4,500 kg-m/min or 33,000 ft-pounds/min. In Metric System of Measurement, therefore, one ‘horsepower’ = 746 Watts.

 

In post-war Germany, ‘PS’ was and is still used – which was/is a functional equivalent of the ‘British’ Horse Power. In reality, it equates as 1.0 HP = 1.07 PS. Today, it seems the Car/Advertisers use ‘PS’ atleast in India to mislead the gullible public - as the same HP/BHP ‘sounds’ a little higher when expressed in PS!

 

3) Energy

 

It’s defined as ‘the Capacity’ of doing work, such as lifting a 10kg weight up to a height of 5 Meters and then ‘giving up’. Or like a Tank full of a Car that can take you, say, 500km before it needs to be filled up again. It’s measure, therefore, is ‘kg-meters’ or Watt-hours etc. A ‘KW/Kilo-Watt’ is simply = 1000 Watts.

 

4) Torque

 

While most of us can imagine that ‘Force’ is a ‘linear’ thing – like 2-people applying ‘X’ amount of force to ‘push’ a Car weighing ‘Y’ kgs, when it comes to ‘Torue’, most people find it difficult to comprehend as to what it is.

 

In other words, it can be defined as the force required to ‘twist or turn’ some thing, For example, like kicking down the starting lever of a Mobike, which actually ‘rotates’ the Bike’s engine to get it going. The measuring ‘Unit’ of such a ‘rotary-force’, therefore, is ‘kg-meters’ or ‘Foot-Pounds’ as its FPS equivalent (not to be confused with the unit of work).

 

Here, ‘kg’ is the ‘linear or tangential force’ applied to the kick pedal – say ‘F’ and ‘meter’ being the ‘radial length’ of the kick-starting lever – say ‘R’. Therefore, the ‘torque’ applied in this instance to the kick-pedal shaft, to rotate the engine, is ‘F x R’ kg-meters.

 

Suffice to say that all ‘rotating’ machines like Engines/Elect. Motors etc., essentially produce a ‘rotary force’ at their 'output shaft’. Since they also

‘rotate’ over a designed range of ‘speeds’ – RPM in their case - they inevitably have a ‘Speed vs Torque Characteristic’ when the two variables/Torque and RPM are plotted on an X-Y axis.

 

Since by definition ‘Power’ is the ‘rate’ of doing work, in case of a Rotating machine or an ICE, Power is simply a straight ‘multiple’ of ‘torque’ and ‘rpm’ - at that particular ‘rpm’. It follows, therefore, that the ‘shape’ of the ‘Power vs Rpm’ Curve of an ICE is quite similar to that of its ‘mother’ Torque vs Rpm’ Curve.

 

Practical difference between Torque and Power

 

We have thus seen that ‘Torque’ is the prime ‘driving force’ that is produced by an Engine and in its units of measurement, there is no ‘time factor’. It’s the Torque, therefore, that’s transmitted to a Vehicle’s drive wheels via its Gearbox. Further, it’s capable of being ‘multiplied’ by its Gearbox Ratios.

 

In other words, if an Engine is producing ‘X’ amount of Torque at its Flywheel and the net gear ratio between it and the drive wheels is 1:Y, then the torque available at the drive wheels would be ‘X x Y’ Units/Kg-Meters. And if the Wheel radius is, say’, 0.5 Meters, then the ‘linear’ force available at the wheels circumference and the road will be X x Y/0.5 or = 2 x X x Y Kgs.

 

To sum-up presently, it’s the Torque capability of an Engine that determines its ‘Acceleration’ abilities.

 

On the other hand, ‘Power’ is a multiple of the Engine Torque AND its ‘Rpm’ – the latter having a ‘Time’ factor in it. It, therefore, follows that the ultimate speed that a vehicle can achieve in any gear is a function of the ‘Power output’ capabilities of an Engine – coz ‘Speed’ has ‘time’ element in it too.

:shock: Never let Professor Gaz of the University of Bournemouth be accused of oversimplification .

Next week Prof. Gaz explains the meaning of life ,the universe and everything .

 

:rofl: :rofl: :rofl:

BHP is how hard you hit a wall

 

Torque is how far the wall moves after you've hit it

WOW, good work dude!!!,

 

I just use the example of a punch when asked that question, ie Horse power is the speed of a punch and torque is the amount of force behind it....

lol, The plot thickens, which of us is right

What he's saying is more torque = more low down grunt = quicker of the mark.

http://www.nitrouskits.co.uk/Technical/torque-horsepower.htm

 

bhp is calculated from your torque figure in relation to engine revs.

 

higher revving engines will produce a higher bhp figure than their torque figure

cool, thanks for all the info, hellraiser that is one detailed reply :D

 

thanks.....

Just to be a little more specific, BHP is related directly to Torque and Revs as shown in the following equation:

 

bbbbbbtorque x revs

BHP = ------------

bbbbbb5252

 

What this means in practice is the at 5252 revs/minute the torque and bhp figure will be the same...

Elementary Definitions

 

:rofl: :rofl: :rofl: elementary! :rofl: :rofl: :rofl:

 

Question: so does that mean that the more torque and bhp you have the better? :smw:

 

Ok, ok - how about a more serious question, but i'm expecting "as elementary" and answer if you wil... and what about bhp/ton or torque per ton... thought i'd throw mass into the equation to get a more practical, applicable answer...

:rofl: :rofl: :rofl: elementary! :rofl: :rofl: :rofl:

 

Question: so does that mean that the more torque and bhp you have the better? :smw:

 

Ok, ok - how about a more serious question, but i'm expecting "as elementary" and answer if you wil... and what about bhp/ton or torque per ton... thought i'd throw mass into the equation to get a more practical, applicable answer...

:xxx:

only joking...

only joking...

and after bhp/ton i was then going to ask about how much power is lost on delivery through gears, wheels, tyres, etc, etc, etc... the "elementary" explanation - as per usual... :smw:

thought i'd be thorough :rofl:

thought i'd be thorough :rofl:

come on, dude - share the knowledge - SET! US! FREE! :hyper: :hyper: :hyper:

come on, dude - share the knowledge - SET! US! FREE! :hyper: :hyper: :hyper:

google is your friend :p

bhp=strength of the arm

torque=size of the spanner

 

thats the way i get my head round it lol, probably wrong like

i use the imagine a wieghtlifter, the bhp is the amount of weight he can lift , the torque is how fast and easy he can lift it

i use the imagine a wieghtlifter, the bhp is the amount of weight he can lift , the torque is how fast and easy he can lift it

 

Other way round ;)

ive always been told, BHP determins your top speed, torque determines how quick ya get there

Correct

 

Torque=acceleration

BHP=top speed

oooh, do win a prize lol, new zed maybe

Torque is often mistaken for power low down the rev range.

Torque is often mistaken for power low down the rev range.

Torque is often mistaken for power low down the rev range.

Stop repeating yourself lol