What is torque in relation to car power?
- Thread starter mgblks
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centurion
Well-Known Member
Re: What is torque in relation to car power?
From the purely seat of the pants perspective, TORQUE is the PULL you feel.
Torque is the FORCE which makes your driving wheels rotate, thus making your car move. The more the torque, the more POWERFUL you feel the car is.
horsepower is the rate of doing work. screw it.
From the purely seat of the pants perspective, TORQUE is the PULL you feel.
Torque is the FORCE which makes your driving wheels rotate, thus making your car move. The more the torque, the more POWERFUL you feel the car is.
horsepower is the rate of doing work. screw it.
jinooi
Well-Known Member
Re: What is torque in relation to car power?
erm...
the best layman illustration is the more torque, the faster the acceleration (to a certain extent), and the greater the hp, the higher the top speed?
not really sure about this. but this is the best analogy i can think of...
erm...
the best layman illustration is the more torque, the faster the acceleration (to a certain extent), and the greater the hp, the higher the top speed?
not really sure about this. but this is the best analogy i can think of...
edlms
Well-Known Member
Re: What is torque in relation to car power?
let me try in my layman terms?
torque is the twisting power (eg imagine to overcome inertia) that rotates the drive shaft that in turn, rotates the wheels. eg a large cc diesel engined vehicle usually has high torque and that would enable to push/pull/tow a heavy trailer/load/mass.
hp is the pulling/pushing power that enables the vehicle to sustain acceleration and reach higher speeds.
some thing like that...?
cheers
let me try in my layman terms?
torque is the twisting power (eg imagine to overcome inertia) that rotates the drive shaft that in turn, rotates the wheels. eg a large cc diesel engined vehicle usually has high torque and that would enable to push/pull/tow a heavy trailer/load/mass.
hp is the pulling/pushing power that enables the vehicle to sustain acceleration and reach higher speeds.
some thing like that...?
cheers
Re: What is torque in relation to car power?
Old thread.. http://www.bmw-sg.com/forums/engine-performance-transmission-section/14358-torque-vs-hp.html
mgblks;427728 said:
Old thread.. http://www.bmw-sg.com/forums/engine-performance-transmission-section/14358-torque-vs-hp.html
Girettom
Well-Known Member
Re: What is torque in relation to car power?
... this is why high revving cars are so cool, because they use the rev range and gearing to make the best use of the torque.
Jack, when you say peak torque, the torque curve is relatively flat through the rpm range right? This is why hp charts have their distinctive curve.
... this is why high revving cars are so cool, because they use the rev range and gearing to make the best use of the torque.
Jack, when you say peak torque, the torque curve is relatively flat through the rpm range right? This is why hp charts have their distinctive curve.
Re: What is torque in relation to car power?
Wheel torque gives you thrust to get moving and there are different ways to arrive at high wheel torque across a sufficiently wide speed range.
Must differentiate between engine torque and wheel torque.
Not really. Depending on the type of engine, it is possible to spend either more or less (or the same) time close to peak torque. It is entirely possible not to use peak torque engine speed at all at certain tracks - as long as you have gears customized to the track.
It's all in the old thread.
centurion;427786 said:
Wheel torque gives you thrust to get moving and there are different ways to arrive at high wheel torque across a sufficiently wide speed range.
Must differentiate between engine torque and wheel torque.
Not really. Depending on the type of engine, it is possible to spend either more or less (or the same) time close to peak torque. It is entirely possible not to use peak torque engine speed at all at certain tracks - as long as you have gears customized to the track.
It's all in the old thread.
Re: What is torque in relation to car power?
the peak torque simply refers to the chart where the highest tq no is dotted vs the rpm it's run on...
eg for S54 engine
365Nm at 4900rpm and 343 bhp...all crank numbers
Here's the chart of the factory car for US market (power is slightly down as u know due to the emission law ie 333bhp 355Nm at 4900rpm )
Girettom;427835 said:
the peak torque simply refers to the chart where the highest tq no is dotted vs the rpm it's run on...
eg for S54 engine
365Nm at 4900rpm and 343 bhp...all crank numbers
Here's the chart of the factory car for US market (power is slightly down as u know due to the emission law ie 333bhp 355Nm at 4900rpm )
Girettom
Well-Known Member
Re: What is torque in relation to car power?
Yup: what I am saying is though, given that hp is a function of torque (as per you equation), the dyno curves we see are because torque is pretty constant on a well tuned engine throughout the rev range. The attached graph from an ariel atom with both torque and bhp.
In other words, I always thought it was better that if you want to compare the power of the car, bhp is only relevant if you are talking about peak bhp, and therefore depends on a whole load of other things like how high the car can rev etc. - a better comparison is probably the torque number, torque being pretty flat.
A high revving car with low torque can give out just as big a bhp number as a not high revving car with lots of torque (aka the american muscle cars)
Yup: what I am saying is though, given that hp is a function of torque (as per you equation), the dyno curves we see are because torque is pretty constant on a well tuned engine throughout the rev range. The attached graph from an ariel atom with both torque and bhp.
In other words, I always thought it was better that if you want to compare the power of the car, bhp is only relevant if you are talking about peak bhp, and therefore depends on a whole load of other things like how high the car can rev etc. - a better comparison is probably the torque number, torque being pretty flat.
A high revving car with low torque can give out just as big a bhp number as a not high revving car with lots of torque (aka the american muscle cars)
Breyton
Well-Known Member
Re: What is torque in relation to car power?
Eh, I thought the dude wanted a layman's explanation? lol
Ok, imagine you are trying to twist the cap off a bottle and it's pretty much stuck. That twisting force you are applying is a torque. Now bear in mind, torque can exist even though there is no motion - you can definitely feel that you are applying that twisting force trying to turn the cap, even though it's stuck and not moving.
So, in engine terms, torque is the ability of the engine to twist/turn the wheels/drive shaft. Imagine you start to twist the wheel of a car to move it forward. Since you cannot humanly apply a large enough force, the car will not move at first. But if you maintain that twisting force long enough, the car may eventually start moving. That's an illustration of low torque.
If you were a giant/superman, you can give a great big twist right from the start and the car immediately starts moving. That's high torque.
So if your engine has high torque, it can start the car moving forward much quicker and you feel that the car is 'powerful'.
Now, as the car moves forward, it is covering distance. The force you are applying, mulitplied by the distance moved, gives you the 'work done'. Work done divided by time taken, gives you power. So if you have high power, you can cover a fixed distance in a shorter time than a car with low power. In the context of the giant/superman example, your power is your ability to maintain that twisting force to move the car forward, in a given timespan.
Eh, I thought the dude wanted a layman's explanation? lol
Ok, imagine you are trying to twist the cap off a bottle and it's pretty much stuck. That twisting force you are applying is a torque. Now bear in mind, torque can exist even though there is no motion - you can definitely feel that you are applying that twisting force trying to turn the cap, even though it's stuck and not moving.
So, in engine terms, torque is the ability of the engine to twist/turn the wheels/drive shaft. Imagine you start to twist the wheel of a car to move it forward. Since you cannot humanly apply a large enough force, the car will not move at first. But if you maintain that twisting force long enough, the car may eventually start moving. That's an illustration of low torque.
If you were a giant/superman, you can give a great big twist right from the start and the car immediately starts moving. That's high torque.
So if your engine has high torque, it can start the car moving forward much quicker and you feel that the car is 'powerful'.
Now, as the car moves forward, it is covering distance. The force you are applying, mulitplied by the distance moved, gives you the 'work done'. Work done divided by time taken, gives you power. So if you have high power, you can cover a fixed distance in a shorter time than a car with low power. In the context of the giant/superman example, your power is your ability to maintain that twisting force to move the car forward, in a given timespan.
