Torque V'sBHP

poreilly101

Can someone help me explain the difference of Torque v's BHP

In my head i understand it but to try an explain it to my other half - it's like trying to explain the off side rule.

You hear about max torque at one point in the rev clock yet max BHP at another...Hmm,I'm confused where is the sweet spot of the engine,max torque or max bhp

When buying a car,should we not be looking at power to weight ratio rather than BHP or Torque?

Thanks ... P

Cuddlesworth

I would have thought it was fairly obvious.

tossy

Torque is for livestock trailers and lorries!

The best explanation of some of them more important motoring terms i heard was...

Understeer is when you hit the fence with the front of the car
Oversteer is when you hit the fence with the rear of the car
BHP determines how fast you hit the fence
Torque determines how far you push the fence into the field!

Torque figures are used by dirty diesel drivers to make themselves feel better.

Graham_B18C

tossy wrote: »

Torque is for livestock trailers and lorries!

The best explanation of some of them more important motoring terms i heard was...

Understeer is when you hit the fence with the front of the car
Oversteer is when you hit the fence with the rear of the car
BHP determines how fast you hit the fence
Torque determines how far you push the fence into the field!

Torque figures are used by dirty diesel drivers to make themselves feel better.

Now thats a bloody good way of puttin it!

Delta Kilo

torque is the turning power of the engine, e.g. pulling a trailer - will the wheels still turn when more of a load is added to the trailer. The more you can pull, the higher the torque.

bhp is Brake Horse Power. Its a measure of engine power. Its the power available at the engine's flywheel which does not take into account the power loss in transmission, wheels, etc. The actual power available at the wheels is lesser than the rated bhp.

BHP and torque are measured using a De Prony brake. To see how it works read this:
http://en.wikipedia.org/wiki/De_Prony_brake

Seweryn

poreilly101 wrote: »

Can someone help me explain the difference of Torque v's BHP

In my head i understand it but to try an explain it to my other half - it's like trying to explain the off side rule.

You hear about max torque at one point in the rev clock yet max BHP at another...Hmm,I'm confused where is the sweet spot of the engine,max torque or max bhp

When buying a car,should we not be looking at power to weight ratio rather than BHP or Torque?

Thanks ... P

Torque is the tendency of a force to rotate an object about an axis. Just as a force is a push or a pull, a torque can be thought of as a twist.
Power is a function of torque and engine speed:
Power = Torque x rotational speed.
To understand it better, just have a look at the torque and power graphs.
When buying a car... You should be looking at what you need really. If the performance is the only factor that you are looking for, then power to weight ratio should be as high as possible (a small Lotus or Ferrari should be OK).

Regards.

tossy

I also have a humdinger of an explanation of the offside rule for women if anyone wants it,they will get it straight away!

EPM

lads, ye obviously dont do big mileage do ye?



PS-you can have fun with torque...

Rowley Birkin QC

EPM wrote: »

PS-you can have fun with torque...

Try 12.0 producing 404 bhp and 1428 ft.lb of torque, thats pretty fun. Pity the top speed was only 36 MPH though.

I've the same problem, understand torque in my head but absolutely no idea how to explain it.

I've attempted to explain it using, small words and visual aids but always resort to waving my hands about and doing a kind of pushing/pulling motion, very strange. I think its just one of those things that you understand or you don't.

Matt Simis

God not again!

Get a drive in a torquey car then in a fast un-torquey car, the difference on the butt dyno is clear as day.

Rowley Birkin QC

Matt Simis wrote: »

God not again!

Get a drive in a torquey car then in a fast un-torquey car, the difference on the butt dyno is clear as day.

Is the Phaeton available for this comparison test?! :pac:

Matt Simis

bigkev49 wrote: »

Is the Phaeton available for this comparison test?! :pac:

Its forsale, tell me you are thinking of buying* and you can see for yourself. I pulled out of a junction on a hill today in sports mode and smacked my head, its insane if you get careless.


*Like the tyrekickers so far!

UhOh

Torque = Pulling power
BHP = Pushing power

Dartz

Engine power is also expressed in kiloWatts, where a Watt is 1 Joule of energy *used* in one second. It is a measure of the rate which the engine does work.

Power (kW= T (N/m) x W(rad/sec, or how fast it's turning)

The higher an engine rev's, to more power it will make. This is partly why a 1 litre motorcyle engine at 13,000 RPM, makes two-three times the power of a 1 litre car engine The actual work done by the engine, is the Torque. And, all other things being equal, for the 1 litre bike engine, and 1 litre car engine (Of course they aren't equal at all, but examples...examples), the torque will be the same, but the higher revving engine will have more power.

Same as you pushing a box. You might push it a hundred yards in an hour, or you might do it in ten minutes. The same amount of work has been done, but one way, you do the work faster, you have more power.

Engine power is the rate at which it makes torque. God I hope that makes sense.

amacachi

Would an easy way of explaining it be that torque is how hard the wheels are turned while horsepower/kilowatts are how quickly the wheels are turned?

Mr.David

UhOh wrote: »

Torque = Pulling power
BHP = Pushing power

Sorry mate, that makes no sense.

Oh, and torque is fun its wicked. So is power, as you cannot really have one without the other....

conneem-TT

Have a read

http://www.vettenet.org/torquehp.html

tossy

BHP,KW,PS call it what you want the power rating of an engine rules.

Fishtits

This old chestnut again

Torque is defined as a turning force and is measured as the force exerted at a distance, ie the instantaneous force at the edge of a flywheel could be 400 Newtons at 0.5 Meter = 200NM

Power is by definition, a measure of work done ie its historical and is not measured but calculated. Work is said to be done when a force moves a distance, so using the above example, 200NM instantaneous force measured on a flywheel turning at 3000 RPM

2Pi x N x T / 60000

= 125 kW

Typically, most engines are designed to produce their peak torque at lower rpm ranges to enhance their driveability and economy. Turbo diesels are particularly good in this respect. If you could check you'd find that most cars are designed that approx 100kph in top gear coincides with max torque, this is usually where the rolling resistance graph crosses the aerodynamic resistance one and is accepted as the optimum cruise speed.

However, don't be fooled by the old adage that torque = acceleration, acceleration depends on the ability of an engine to do work ie there is a time factor. Power = acceleration, it may mean having an engine screaming, but a car will always accelerate faster when its engine is producing max power than when it is producing max torque.

then there's also tractive effort... but we won't go there

Fishtits, a little rusty, Saturday night, sad b***erd...

-Chris-

The way I explain the difference to customers is:

Imagine yourself cycling your bike. When you were going hard uphill - out of the saddle, swinging out of the handlebars, using all the strength your thighs could muster - that was you at max torque.

Now imagine when you were buzzing along on a flat road, legs spinning fairly comfortably, but going as fast as you could comfortably go. You could probably spin your legs faster, but the additional effort you put in wouldn't make an equivelant difference in your speed (due to air resistance etc.), that was you at max power.

Matt Simis

You could expand on the cycling analogy even further

On the hill;
Same bike/gears, a muscle clad (torque) man could likely cycle up a steep hill smoothly and consistantly but a more athletic man (bhp) could cycle on less severe inclines faster.

On the flat;
The strong man will push the stationary pedal harder from a stop for the first couple of pedel revolutions, hence the feeling torque is faster for acceleration. It is, but only from 0 to slightly moving.
The athletic man starts slower but quickly increases his bikes speed, in a more linear and rapidily accellerating fashion.

Simply, if you have sufficient momentum you no longer need torque, like pushing a kid on a swing, once its going, a light push keeps it going.

robbie99

From the driver's perspective....

Torque is how strong an engine feels when you're accelerating.

How fast you can ultimately go is determined by power.

UhOh

Mr.David wrote: »

Sorry mate, that makes no sense.

oh course it does. Torque is more important for pulling loads. Same as if you've ever driven a high torque car up a hill. It'll have great pull in the low revs so you dont need to down change gear. It'll sail up a steep hill at low rev's whereas something with low torque will splutter & struggle forcing you to change to a lower gear & higher revs.
The power then determines how fast the engine can push the car along the road

Neilw

UhOh wrote: »

oh course it does. Torque is more important for pulling loads. Same as if you've ever driven a high torque car up a hill. It'll have great pull in the low revs so you dont need to down change gear. It'll sail up a steep hill at low rev's whereas something with low torque will splutter & struggle forcing you to change to a lower gear & higher revs.
The power then determines how fast the engine can push the car along the road

Push or pull it's the same thing, a force acting on an object.
It will make no difference if the force is from the front or the rear.

UhOh

Neilw wrote: »

It will make no difference if the force is from the front or the rear.

when I say push & pull I dont literally mean the force is coming from the front or the rear. Obviously the engine remains in the same place. So the push & pull is an analogy of what torque & power do

preilly79

UhOh wrote: »

So the push & pull is a bad analogy of what torque & power do

FYP

gears

I may be wrong but how I always thought of power and torque was....
Imagine the old school example of using a lever to move a rock, power could be equated to the force applied on the end of the lever and torque the length of the lever.
It's not a motoring explaination but it does explain the use of two forces (for want of a better word) to achieve a single task, be it moving a rock or a car.

UhOh

preilly79 wrote: »

FYP

lets see if you can explain it better so

preilly79

UhOh wrote: »

lets see if you can explain it better so

Gladly.

You're fond of analogies so i'll stick with those.

1. Let's say you have a jam jar - the lid is closed and you want to open it, but it's on very tight.
2. you grip the jar in your left hand and the lid in your right. you try to twist the lid off. it doesn't budge. right now you're applying a torque.
3. this torque can be measured. it has no time-factor. you could be doing this for 5 seconds or a year, you'd still be applying a torque.
4. Finally, the lid lets go and you can unscrew it. You're still applying a turning force, or torque, but after a turn or two the lid comes off. it's taken two turns, or lets say two revolutions to remove the lid.
5. you've applied a torque (t), over two revolutions (r). There's a time factor involved (the time taken to do the two revolutions).
6. Power is the amount of torque applied DURING the opening of the lid. it has a time factor. it can't be measured, it's calculated.

OR to make even simpler:

Torque is a measure of work. Power is the RATE at which the work is being done (see the time value?).

peasant

historically, horse power is the unit taken to measure the power of a steam engine.

Horses were used to pump water out of mine shafts by walking round in circles, driving the shaft of the pump. Your average horse could pump x gallons of water per hour ...that's one horse power. The new fangled steam engines then could be sold as having the power of so many horses ...a unit that made sense at the time.


But as you can see ...horse power has nothing to do with speed, acceleration, force or the push in your back when you hit the loud pedal ...at least not directly.

All it does is tell you which machine is capable of how much work over time.
Good for comparing machines/engines ...not so good once you bring speed, acceleration, hills and big boys into it

poreilly101

Some great posts , thanks for everyone taking the time to reply

By the sound of things, we should be looking at KW? Not torque nor bhp?

preilly79

poreilly101 wrote: »

Some great posts , thanks for everyone taking the time to reply

By the sound of things, we should be looking at KW? Not torque nor bhp?

KW, aka BHP, is power

Actually, I should be more specific. both are a measure of power, but are not the same numerical values.

HashSlinging

Torque seems to win races. A lot of races.

All this torque is cheap.

Matt Simis

HashSlinging wrote: »

Torque seems to win races. A lot of races.

"BHP sells cars, torque wins races.."
That adage has been debunked, there are some articles online about it. The car with the highest torque figure is still slower than a car with somewhat less torque that has aggressive gearing or high RPM, or both.

HashSlinging

I know fecking US journo's never heard of the Le Mans 24hr and the BTCC.

PirateShampoo

Torque wins races
BHP sells cars

grateface

poreilly101 wrote: »

Some great posts , thanks for everyone taking the time to reply

By the sound of things, we should be looking at KW? Not torque nor bhp?

No mate. BHP is the same thing. 1 horsepower is 746Watts. or .746KW
The Horsepower rating of cars is determined under lab conditions by measuring the output from the cylinders. The actual power transmitted to the wheels is usually 10-20% less than from what was achieved from the pistons. Mainly frome heat losses in the exhaust, transmission and a load of other sh1te on the way to the wheels.

As for the main question:
Torque (J or Nm) = work done per cycle
Power (J.s-1 or W) = work done per unit time

Power is got from the torque. Ther actual torque is mainly determined form the gearing and how efficient it is. This graph from the car we study in UCD might help ya picture it better.

PirateShampoo

Force, Work and Time
If you have a one pound weight bolted to the floor, and try to lift it with one pound of force (or 10, or 50 pounds), you will have applied force and exerted energy, but no work will have been done. If you unbolt the weight, and apply a force sufficient to lift the weight one foot, then one foot pound of work will have been done. If that event takes a minute to accomplish, then you will be doing work at the rate of one foot pound per minute. If it takes one second to accomplish the task, then work will be done at the rate of 60 foot pounds per minute, and so on.
In order to apply these measurements to automobiles and their performance (whether you're speaking of torque, horsepower, newton meters, watts, or any other terms), you need to address the three variables of force, work and time.

Awhile back, a gentleman by the name of Watt (the same gent who did all that neat stuff with steam engines) made some observations, and concluded that the average horse of the time could lift a 550 pound weight one foot in one second, thereby performing work at the rate of 550 foot pounds per second, or 33,000 foot pounds per minute, for an eight hour shift, more or less. He then published those observations, and stated that 33,000 foot pounds per minute of work was equivalent to the power of one horse, or, one horsepower.

Everybody else said OK. :-)

For purposes of this discussion, we need to measure units of force from rotating objects such as crankshafts, so we'll use terms which define a *twisting* force, such as foot pounds of torque. A foot pound of torque is the twisting force necessary to support a one pound weight on a weightless horizontal bar, one foot from the fulcrum.

Now, it's important to understand that nobody on the planet ever actually measures horsepower from a running engine. What we actually measure (on a dynomometer) is torque, expressed in foot pounds (in the U.S.), and then we *calculate* actual horsepower by converting the twisting force of torque into the work units of horsepower.

Visualize that one pound weight we mentioned, one foot from the fulcrum on its weightless bar. If we rotate that weight for one full revolution against a one pound resistance, we have moved it a total of 6.2832 feet (Pi * a two foot circle), and, incidently, we have done 6.2832 foot pounds of work.

OK. Remember Watt? He said that 33,000 foot pounds of work per minute was equivalent to one horsepower. If we divide the 6.2832 foot pounds of work we've done per revolution of that weight into 33,000 foot pounds, we come up with the fact that one foot pound of torque at 5252 rpm is equal to 33,000 foot pounds per minute of work, and is the equivalent of one horsepower. If we only move that weight at the rate of 2626 rpm, it's the equivalent of 1/2 horsepower (16,500 foot pounds per minute), and so on. Therefore, the following formula applies for calculating horsepower from a torque measurement:


Torque * RPM

Horsepower =

---

5252


This is not a debatable item. It's the way it's done. Period.
The Case For Torque
Now, what does all this mean in carland?
First of all, from a driver's perspective, torque, to use the vernacular, RULES :-). Any given car, in any given gear, will accelerate at a rate that *exactly* matches its torque curve (allowing for increased air and rolling resistance as speeds climb). Another way of saying this is that a car will accelerate hardest at its torque peak in any given gear, and will not accelerate as hard below that peak, or above it. Torque is the only thing that a driver feels, and horsepower is just sort of an esoteric measurement in that context. 300 foot pounds of torque will accelerate you just as hard at 2000 rpm as it would if you were making that torque at 4000 rpm in the same gear, yet, per the formula, the horsepower would be *double* at 4000 rpm. Therefore, horsepower isn't particularly meaningful from a driver's perspective, and the two numbers only get friendly at 5252 rpm, where horsepower and torque always come out the same.

In contrast to a torque curve (and the matching pushback into your seat), horsepower rises rapidly with rpm, especially when torque values are also climbing. Horsepower will continue to climb, however, until well past the torque peak, and will continue to rise as engine speed climbs, until the torque curve really begins to plummet, faster than engine rpm is rising. However, as I said, horsepower has nothing to do with what a driver *feels*.

You don't believe all this?

Fine. Take your non turbo car (turbo lag muddles the results) to its torque peak in first gear, and punch it. Notice the belt in the back? Now take it to the power peak, and punch it. Notice that the belt in the back is a bit weaker? Fine. Can we go on, now? :-)


The Case For Horsepower
OK. If torque is so all-fired important, why do we care about horsepower?
Because (to quote a friend), "It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*.

For an extreme example of this, I'll leave carland for a moment, and describe a waterwheel I got to watch awhile ago. This was a pretty massive wheel (built a couple of hundred years ago), rotating lazily on a shaft which was connected to the works inside a flour mill. Working some things out from what the people in the mill said, I was able to determine that the wheel typically generated about 2600(!) foot pounds of torque. I had clocked its speed, and determined that it was rotating at about 12 rpm. If we hooked that wheel to, say, the drivewheels of a car, that car would go from zero to twelve rpm in a flash, and the waterwheel would hardly notice :-).

On the other hand, twelve rpm of the drivewheels is around one mph for the average car, and, in order to go faster, we'd need to gear it up. To get to 60 mph would require gearing the wheel up enough so that it would be effectively making a little over 43 foot pounds of torque at the output, which is not only a relatively small amount, it's less than what the average car would need in order to actually get to 60. Applying the conversion formula gives us the facts on this. Twelve times twenty six hundred, over five thousand two hundred fifty two gives us:

6 HP.

Oops. Now we see the rest of the story. While it's clearly true that the water wheel can exert a *bunch* of force, its *power* (ability to do work over time) is severely limited.


At The Dragstrip
OK. Back to carland, and some examples of how horsepower makes a major difference in how fast a car can accelerate, in spite of what torque on your backside tells you :-).
A very good example would be to compare the current LT1 Corvette with the last of the L98 Vettes, built in 1991. Figures as follows:


Engine Peak HP @ RPM Peak Torque @ RPM

---

---

---

L98 250 @ 4000 340 @ 3200

LT1 300 @ 5000 340 @ 3600


The cars are geared identically, and car weights are within a few pounds, so it's a good comparison.
First, each car will push you back in the seat (the fun factor) with the same authority - at least at or near peak torque in each gear. One will tend to *feel* about as fast as the other to the driver, but the LT1 will actually be significantly faster than the L98, even though it won't pull any harder. If we mess about with the formula, we can begin to discover exactly *why* the LT1 is faster. Here's another slice at that formula:


Horsepower * 5252

Torque =

---

RPM


If we plug some numbers in, we can see that the L98 is making 328 foot pounds of torque at its power peak (250 hp @ 4000), and we can infer that it cannot be making any more than 263 pound feet of torque at 5000 rpm, or it would be making more than 250 hp at that engine speed, and would be so rated. In actuality, the L98 is probably making no more than around 210 pound feet or so at 5000 rpm, and anybody who owns one would shift it at around 46-4700 rpm, because more torque is available at the drive wheels in the next gear at that point.
On the other hand, the LT1 is fairly happy making 315 pound feet at 5000 rpm, and is happy right up to its mid 5s redline.

So, in a drag race, the cars would launch more or less together. The L98 might have a slight advantage due to its peak torque occuring a little earlier in the rev range, but that is debatable, since the LT1 has a wider, flatter curve (again pretty much by definition, looking at the figures). From somewhere in the mid range and up, however, the LT1 would begin to pull away. Where the L98 has to shift to second (and throw away torque multiplication for speed), the LT1 still has around another 1000 rpm to go in first, and thus begins to widen its lead, more and more as the speeds climb. As long as the revs are high, the LT1, by definition, has an advantage.

Another example would be the LT1 against the ZR-1. Same deal, only in reverse. The ZR-1 actually pulls a little harder than the LT1, although its torque advantage is softened somewhat by its extra weight. The real advantage, however, is that the ZR-1 has another 1500 rpm in hand at the point where the LT1 has to shift.

There are numerous examples of this phenomenon. The Integra GS-R, for instance, is faster than the garden variety Integra, not because it pulls particularly harder (it doesn't), but because it pulls *longer*. It doesn't feel particularly faster, but it is.

A final example of this requires your imagination. Figure that we can tweak an LT1 engine so that it still makes peak torque of 340 foot pounds at 3600 rpm, but, instead of the curve dropping off to 315 pound feet at 5000, we extend the torque curve so much that it doesn't fall off to 315 pound feet until 15000 rpm. OK, so we'd need to have virtually all the moving parts made out of unobtanium :-), and some sort of turbocharging on demand that would make enough high-rpm boost to keep the curve from falling, but hey, bear with me.

If you raced a stock LT1 with this car, they would launch together, but, somewhere around the 60 foot point, the stocker would begin to fade, and would have to grab second gear shortly thereafter. Not long after that, you'd see in your mirror that the stocker has grabbed third, and not too long after that, it would get fourth, but you'd wouldn't be able to see that due to the distance between you as you crossed the line, *still in first gear*, and pulling like crazy.

I've got a computer simulation that models an LT1 Vette in a quarter mile pass, and it predicts a 13.38 second ET, at 104.5 mph. That's pretty close (actually a tiny bit conservative) to what a stock LT1 can do at 100% air density at a high traction drag strip, being powershifted. However, our modified car, while belting the driver in the back no harder than the stocker (at peak torque) does an 11.96, at 135.1 mph, all in first gear, of course. It doesn't pull any harder, but it sure as hell pulls longer :-). It's also making *900* hp, at 15,000 rpm.

Of course, folks who are knowledgeable about drag racing are now openly snickering, because they've read the preceeding paragraph, and it occurs to them that any self respecting car that can get to 135 mph in a quarter mile will just naturally be doing this in less than ten seconds. Of course that's true, but I remind these same folks that any self-respecting engine that propels a Vette into the nines is also making a whole bunch more than 340 foot pounds of torque.

That does bring up another point, though. Essentially, a more "real" Corvette running 135 mph in a quarter mile (maybe a mega big block) might be making 700-800 foot pounds of torque, and thus it would pull a whole bunch harder than my paper tiger would. It would need slicks and other modifications in order to turn that torque into forward motion, but it would also get from here to way over there a bunch quicker.

On the other hand, as long as we're making quarter mile passes with fantasy engines, if we put a 10.35:1 final-drive gear (3.45 is stock) in our fantasy LT1, with slicks and other chassis mods, we'd be in the nines just as easily as the big block would, and thus save face :-). The mechanical advantage of such a nonsensical rear gear would allow our combination to pull just as hard as the big block, plus we'd get to do all that gear banging and such that real racers do, and finish in fourth gear, as God intends. :-)

The only modification to the preceeding paragraph would be the polar moments of inertia (flywheel effect) argument brought about by such a stiff rear gear, and that argument is outside of the scope of this already massive document. Another time, maybe, if you can stand it :-).


At The Bonneville Salt Flats
Looking at top speed, horsepower wins again, in the sense that making more torque at high rpm means you can use a stiffer gear for any given car speed, and thus have more effective torque *at the drive wheels*.
Finally, operating at the power peak means you are doing the absolute best you can at any given car speed, measuring torque at the drive wheels. I know I said that acceleration follows the torque curve in any given gear, but if you factor in gearing vs car speed, the power peak is *it*. An example, yet again, of the LT1 Vette will illustrate this. If you take it up to its torque peak (3600 rpm) in a gear, it will generate some level of torque (340 foot pounds times whatever overall gearing) at the drive wheels, which is the best it will do in that gear (meaning, that's where it is pulling hardest in that gear).

However, if you re-gear the car so it is operating at the power peak (5000 rpm) *at the same car speed*, it will deliver more torque to the drive wheels, because you'll need to gear it up by nearly 39% (5000/3600), while engine torque has only dropped by a little over 7% (315/340). You'll net a 29% gain in drive wheel torque at the power peak vs the torque peak, at a given car speed.

Any other rpm (other than the power peak) at a given car speed will net you a lower torque value at the drive wheels. This would be true of any car on the planet, so, theoretical "best" top speed will always occur when a given vehicle is operating at its power peak.

"Modernizing" The 18th Century
OK. For the final-final point (Really. I Promise.), what if we ditched that water wheel, and bolted an LT1 in its place? Now, no LT1 is going to be making over 2600 foot pounds of torque (except possibly for a single, glorious instant, running on nitromethane), but, assuming we needed 12 rpm for an input to the mill, we could run the LT1 at 5000 rpm (where it's making 315 foot pounds of torque), and gear it down to a 12 rpm output. Result? We'd have over *131,000* foot pounds of torque to play with. We could probably twist the whole flour mill around the input shaft, if we needed to :-).

The Only Thing You Really Need to Know
Repeat after me. "It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*."

preilly79

PirateShampoo wrote: »

Force, Work and Time
If you have a one pound weight bolted to the floor ...

Wouldn't it have been easier to paste the links where you copied all that from?

peasant

preilly79 wrote: »

Wouldn't it have been easier to paste the links where you copied all that from?

nevermind fairer to the people that wrote the initial articles

seanybiker

I normally explain it as bhp is how hard ya hit a wall and torque is how for ya push the wall. Keep it simple then everyone understands it.

PirateShampoo

preilly79 wrote: »

Wouldn't it have been easier to paste the links where you copied all that from?

I would but its from a private forum

Merch

torque is turning power, it could be described as rotational force
T=Fr thats like torque is = to force by distance

HP or BHP is the ability to do work in a certain amount (unit) of time

Power is work/time and work is force x distance

Power = force x distance/time

Joule (J) is SI the unit of work
1J is when a force of 1N (newton)moves an object 1m (metre)
1J= 1Nm

The unit of torque is the Nm

That kinda makes it look like torque is = work

Power seem to be the ability to do that work or torque in a given time.

The bigger the engine theoretically the greater the ability to do work but I guess people who are more in tune with 2/4stroke engines can give the practical details of how that can be different (smaller engines with super/turbochargers) or refute that.

Fishtits

This subject is so simple in terms of physics, or engineering science yet tends to get dragged to infinity by your average poster...

You can't f*ck with physics, take it or leave it.

UhOh

preilly79 wrote: »

Gladly.

excellent analogy but can anyone clearly explain it in terms of how it relates to a car, not jam jars.

I drive a Focus ST & I remember Jeremy Clarkson's original TG review saying the torque it chucks out is immense. I know what he means from driving it so I guess it goes right back to the original point of the thread. I know what it is I just cant put it into words. My explaination makes perfect sense to me, obviously not to others

Fishtits

OK, I'm throwing the towel in. its all been explained in infinite detail previously.

Wheres the Shiraz

Sqaull20

Agree UhOh lots of instant shove from the torque for easy progress is great.Focus ST are no performance slayers but modded, real world, in-gear whatever its quick.It depends what you want from a car.If you get the ST in the right gear, at the right time, it can feel a LOT faster than much bigger cars, but other times they feel quicker.

preilly79

UhOh wrote: »

excellent analogy but can anyone clearly explain it in terms of how it relates to a car, not jam jars.

Sorry if the jam jar analogy doesn't work for you, that's as much as I could distill the forces at work

the concept is the same: turning forces being generated either by your hand, or an engine, are exactly the same no matter where they are applied. applying the theory to your car is easy ... if you understand the basics. clearly the concept is too complicated for some.

wanting it expressed in terms of "push-you-into-your-seat" force is pointless, as both an engine with large amounts of torque or high Bhp will result in the same sensation. indeed an engine with no torque whatsoever can give that kick in the pants feeling.

conneem-TT

preilly79 wrote: »

Wouldn't it have been easier to paste the links where you copied all that from?

peasant wrote: »

nevermind fairer to the people that wrote the initial articles

PirateShampoo wrote: »

I would but its from a private forum

It's all copied from the link I posted on page 2 here , not a forum.

http://www.boards.ie/vbulletin/showpost.php?p=59789695&postcount=17

Cyrus

isnt it true that if a car with 300bhp and say 200 torques (to use the TG phraseology) and car with 270 bhp and 400 torques, all other things being equal, both raced up a hill, the higher bhp would be faster....

PirateShampoo

conneem-TT wrote: »

It's all copied from the link I posted on page 2 here , not a forum.

http://www.boards.ie/vbulletin/showpost.php?p=59789695&postcount=17

Actually i copyed it from http://www.isdc.ie/discussion/index.php?topic=6778.0
And whats the problem?