How does torque affect car performance?

[Vegard]

Logic time
1. Gears multiply torque
2. Put gears on that "double your torque"
3. Make 400hp car race with 800hp car because it's torque has been doubled!

A 2:1 gearing doubles the wheel torque but it also reduces the wheel speed by 50 %, leaving wheel power unaffected.

At the wheels: 2 (torque) x 0.5 (rpm) = 1 (power).

 

[Scaff]

2 x 0.5 = 1.

A 2:1 gearing doubles the wheel torque but it also reduces the wheel speed by 50 %, leaving wheel power unaffected.

Exactly.

 

[Griffith500]

Let's make it simpler.
Show me an engine, with torque ratings, change the gearing, and show me the new higher torque readings.

I already know it doesn't exist.

Also, torque is defined as a rotational force. Horsepower is torque per minute. Rotational force per minute. But it's rotational force that isn't torque? Ok.

Torque is a force applied at a distance from an axis, which would indeed induce rotation if free to do so. The crucial difference is that you can have torque without rotation, but you don't do any work if you don't move something.

Power is specifically energy per time, not rotational force per time, which doesn't really mean anything. In the typical calculation of the work done by applying a torque over a rotation, the distance aspect gets obscured thanks to imperial units - it is captured in the 5252 figure, follow the link for details:
http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm#equation

It is important to keep track of the speeds of things in order to properly assess power; torque can vary, but in thermodynamic terms, the total power must remain constant (IN = OUT).
By doubling the rotation speed, you double the distance per unit time, and hence double power output for a constant torque (force) output. Conversely, by doubling torque through gearing, you must consequently halve the output speed, and so power is unaffected.

 

[7HO]

You can increase the torque applied, at a given speed.
I detailed this for you already.
But I'll do it a bunch of times in every post so it gets ignored even more.

A gear optimized for torque(horsepower) at 30mph, has more torque at 30mph. What about 40mph? Will a gear optimized for maximum torque applied at 30mph apply even more torque at 40mph? Nope, but a longer gear (that, as you claim) doesn't "multiply torque as much") that is optimized for 40mph will give you more torque at 40mph.
"Without multiplying torque more???" Gears don't multiply torque.

Gears multiply torque applied at a given speed, on the concept that what is attached to them(engine) has more power at a faster speed.

Oh my god, you haven't read anything and couldn't be much more wrong.

Multiplied.
*Applied torque at a given speed. A gear that "multiplies" torque optimally for 30mph, won't be applying as much torque at 40mph as a longer gear optimized for 40mph.
You're also completely ignoring the fact the engine might make significantly more or less than half the power at half the rpm.
You also seem to be ignoring that horsepower and torque, are both torque.
But obviously you either didn't read or understand my post.

Sorry mate but you don't understand what you are talking about. Read the links, it isn't hard to understand and you are arguing with science here. To simplify what you will find

Input torque multiplied by gear ratio = output torque

In other words gears multiple torque, it doesn't get much simpler than that.

This is a universal principle engineering depends on.

Your nonsense of talking about speed is irrelevant as torque is a moment of rotational force, it is independent of speed. Power is a function of speed and torque but torque does not have a speed component, it is simply a measure of rotational force and torque can be measured when stationary.

Throughout your post you seem to be confused and you seem to use torque and power interchangeably. They are not the same thing. Power is a function of torque and speed. But Torque is just a measure of how much force is being applied at that point. And yes the torque changes in an engine at different RPM but that is a factor of engine design and efficiency and not in itself a result of speed. We can measure the torque an engine produces at any speed and then we can multiply that with gears, the result will be constant, the gears will multiply the torque the engine is producing. If the engine produces 100Nm at 1000 rpm a 4:1 gear ratio will multiply that to 400Nm at 250 rpm at the other side. But that engine might produce 200Nm at 4000rpm and those same gears will then produce 800Nm at 1000rpm of output torque.

Whatever torque the engine produces will be multiplied by the gears, your confusion seems to stem from you not properly understand how torque is developed by an engine and how torque is not constant at rpm in an engine and varies according to the torque curve designed into that engine. But just know that gears always multiply that torque and if an engine produces a certain amount of torque at 100 rpm the gears will multiply that according to their ratio and they will do the same at 200 rpm. The output will always be the same, input torque x gear ratio = output torque. Yes there is a trade for rpm at an equal ratio because the gears can't invent power and power is a function of torque and speed. What this means is torque is multiplied, power remains the same, speed is divided. The relationship between these will always stay constant so by understanding this relationship we can use gears and calculate the result.

 

[RichiPuppy]

Not without the right gearing it doesn't.

I'm fairly certain that every big-rig has significantly more torque than my V40 D4, yet I know who would win in a drag race.

That has a lot more to do with weight than it has anything to do with gearing.

 

[Scaff]

That has a lot more to do with weight than it has anything to do with gearing.

Weight is a factor, but that's what determines the gearing.

You need the gearing to overcome the much higher level of rolling resistance.

 

[Zenmervolt]

Weight is a factor, but that's what determines the gearing.

You need the gearing to overcome the much higher level of rolling resistance.

Another big factor is that an over-the-road diesel engine in a semi typically has only about 1,000 to 1,500 rpm between idle and redline. They have very, very narrow powerbands.

 

[Scaff]

Another big factor is that an over-the-road diesel engine in a semi typically has only about 1,000 to 1,500 rpm between idle and redline. They have very, very narrow powerbands.

Yep, which you resolve once again with gearing.

 

[Griffith500]

Another big factor is that an over-the-road diesel engine in a semi typically has only about 1,000 to 1,500 rpm between idle and redline. They have very, very narrow powerbands.

This is something that can be hooked back into the original point of the thread, more in terms of the kinds of vehicles found in the game.

Typically, "high torque" engines - i.e. those designed to generate their peak lower down in the rev range - have something of an advantage over those that generate the peak higher up. That advantage relates to gearing: the low-lugger can use wider gearing, whilst the high-revver needs more gears closer together.

Since engine tuning is based on acoustics (at least once you start chasing the big figures for volumetric efficiency / BMEP), the nature of the "power band" is somewhat linear. E.g. it may extend from 6000 to 8000 rpm in your typical NA road super-sporty machine, a spread of 2000 rpm - but that same spread applies to a lively muscle car from say 4000 rpm to 6000 rpm, or a big V-Twin cruiser from 2000 to 4000 rpm.

The difference is that 4/2 is larger than 6/4 is larger than 8/6 - 2 vs. 1.5 vs. 1.33.

So gearing clearly has to be closer to stay in the power band for the higher revving engine, which means more gears to cover the same speed range. This is "torque's" principle advantage - think back to those old 3-speed Chaparrals and the 9-speed Honda GP bikes of the '60s etc.

Not only can you use fewer ratios and compromise less for a dual purpose vehicle (sporty / practical), but you find that in-gear flexibility is also improved because you're never that far away from the power-band, in relative terms, when cruising or caught "between gears" - the latter especially on track.

 

[Zenmervolt]

Yep, which you resolve once again with gearing.

In the case of OTR semis, lots and lots of gearing. 18-21 speeds in many cases. :-D

 

[Scaff]

In the case of OTR semis, lots and lots of gearing. 18-21 speeds in many cases. :-D

Yep.

My own main experience of it is from off-roading, so a much smaller 8 to 12 depending on the car in question.

Teaching people how to drive low ratio boxes is fun, can take a while for the penny to drop as to what is going on, particularly a low ratio 1st gear hill descent with feet off the pedals. So slow that it freaks people out.

 

[SleezyBigSlim]

Not without the right gearing it doesn't.

I'm fairly certain that every big-rig has significantly more torque than my V40 D4, yet I know who would win in a drag race.


Yes they do.



Nope. Torque and power are related by they are most certainly not the same thing at all.

The base values will be the same at the engine for any given gear, but they will not be the same at the wheels, as gears are force multipliers but not power multipliers. Its basic physics. Its why crowbars, wreaking bars, levers, pulleys and gears work.

If they were not force multipliers the entire industrial age would not have happened!



It does indeed, but bhp isn't torque.



Nope. You can potentially accelerate faster with different gears because they increase the work the wheel is doing by multiplying the torque from the engine to the driven wheels.



BHP's still not torque.


Which has nothing to do with torque.


No one has said it does, because BHP still isn't torque.



Strawman based on your own inability to understand that BHP isn't torque.

Its really quite simple.

BHP is a measure of power, Torque is a measure of force (ratational force in this case) and gearboxes are a torque multiplier.

https://en.wikipedia.org/wiki/Horsepower
https://en.wikipedia.org/wiki/Torque
https://en.wikipedia.org/wiki/Torque_multiplier
https://en.wikipedia.org/wiki/Gear_train#Torque_ratio

https://www.google.co.uk/search?q=e...69i59j69i57.5876j0j7&sourceid=chrome&ie=UTF-8

You are correct in that the right gearing is needed to take advantage of high torque but thats self explanatory. Doesnt change the fact that real life sports cars that come stock from the delearship are already tuned from the factory so it really isnt worth mentioning. I plan on buying the 2018 Mustang GT wich will come with a 10 speed automatic transmission paired to a 450hp 5.0 v8. The torque is already there, what you're saying is irrelevent we're talking about road cars here. My point is the torque to have fast acceloration is already there in a sports car. You wont need to tune the gears unless you're going to a race track but you will need to add hp too because just tuning the gears without adding power which in turn will also add torque is useless.

 

[7HO]

This is something that can be hooked back into the original point of the thread, more in terms of the kinds of vehicles found in the game.

Typically, "high torque" engines - i.e. those designed to generate their peak lower down in the rev range - have something of an advantage over those that generate the peak higher up. That advantage relates to gearing: the low-lugger can use wider gearing, whilst the high-revver needs more gears closer together.

Since engine tuning is based on acoustics (at least once you start chasing the big figures for volumetric efficiency / BMEP), the nature of the "power band" is somewhat linear. E.g. it may extend from 6000 to 8000 rpm in your typical NA road super-sporty machine, a spread of 2000 rpm - but that same spread applies to a lively muscle car from say 4000 rpm to 6000 rpm, or a big V-Twin cruiser from 2000 to 4000 rpm.

The difference is that 4/2 is larger than 6/4 is larger than 8/6 - 2 vs. 1.5 vs. 1.33.

So gearing clearly has to be closer to stay in the power band for the higher revving engine, which means more gears to cover the same speed range. This is "torque's" principle advantage - think back to those old 3-speed Chaparrals and the 9-speed Honda GP bikes of the '60s etc.

Not only can you use fewer ratios and compromise less for a dual purpose vehicle (sporty / practical), but you find that in-gear flexibility is also improved because you're never that far away from the power-band, in relative terms, when cruising or caught "between gears" - the latter especially on track.

That's part of the puzzle. The advantage you speak of has been drastically reduced with modern gearbox/transmission design and other technologies.

As I'm sure you appreciate this isn't a simple subject that can be answered with a simple post.

Top speed is determined primarily by power, drag coefficient and frontal area.

Power is determined by HP = Torque x RPM ÷ 5252.

Acceleration is far more complex. Ultimately Chrysler were right to simplify acceleration as a result of power to weight because the result is accurate enough for general use but at the bleeding edge of competition it is a far more complex subject.

Available grip
Torque in the operating range
Gearing
Time lost to gear changes
and Weight

are all critical in the performance of a vehicle for racing purposes.

Grip limit is important because too much torque will overcome the limits and result in less acceleration. Grip limits are a factor of tyres, chassis design and Weight on the tyres. The torque seen at the tyres is a result of the Torque produced by the engine multiplied by the gearing. In a dream world the torque at the tyres should be at the limit of grip but not exceed it and this would result in the ultimate acceleration. At this point you could be forgiven for thinking torque is more important than power in regards to acceleration but you would be wrong.

Ultimately average Power is more important than Torque for the purpose of acceleration but remember from the equation Power is a product of Torque and RPM. The reason for this is we always use Gearing so by understanding the formula earlier and how gearing can be applied it should be easy to understand why more power at a higher RPM can be more effective than higher torque at a lower RPM. Ultimately whichever results in a higher torque number at the tyres after optimal Gearing is applied that remains within the limits of the tyres grip will result in better performance.

So Gearing is how we effectively use the power/torque available and at that point considering our effective operating range, a significant factor is average power/torque in that range not the peak. The peak is only important to top speed.

Unfortunately in the real world as pointed out by Griffith500 Time is lost to gear changes. Thankfully this issue is being reduced with advances in technology.

And then there is Weight. While weight is a factor effecting grip more weight is harder to move. Just look to Colin Chapman when it comes to weight. "Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere." but he was also know for variations of the William Bushnell Stout quote "Simplicate, and add lightness". I've also seen quotes that indicate he was familiar with Antoine de Saint-Exupéry idea "Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." and Colin Chapman is reported to have said "Any car which holds together for a whole race is too heavy."

 

[rex1825]

Torque drives car, horsepower sells it

Take for example the Mazda 6 featured in latest N200 daily race. It is a diesel, so it is a torque powerhouse, it's max power comes around 4500 rpm, so anything between 3000-4500 is what it will give it more accel.
It is sad to see how people are using AT, and it is simply not adjusted for this car, since it does go all up to almost 5500rpm, where this car has no power. Try shifting it at or below 4500rpm, then try pulling it up to 5500rpm, and watch how speed is going up...

Cheers...

 

[Dragonwhisky]

I'm not certain I fully understand all the points and counterpoints being made in this discussion but I've always read and been told that HP is a calculated value derived from measurable, in foot pounds and inch pounds of pressure, torque values and, up until this conversation, unknown to me, revolutions per minute with constant of 5,252 for peak HP values. Is that RPM value the point at which the HP and torque curves always intercept?

I look at horsepower in basically the same way I understand the derivative nature of watts in an electrical environment. Watts are a product of voltage and amperage. I'm not sure if the comparison is apt here but in my mind amperage would equate to torque while voltage correlates to RPMs. For instance, an electrical device that draws 2 amps at 120volts will, as a general rule, draw 1 amp at 240 volts. In either case it's still a 240watt device. Thinking about this comparison has me wondering if it's actually any good as an example but I can't think of why it's bothering me that it isn't.

As far as vehicles are concerned, be them cars, motorcycles, bicycles or trucks, horsepower is how fast you can go, torque determines how long it takes to get to how fast you can go. Near as I can tell there is only one other value to take into account for how fast you can go and how long it takes you to get there and that is how much mass you have to move. Aerodynamic, friction and any other factors can all be lumped in that weight value.

As an example of how weight affects the top speed and how fast you get there, I have 2 vehicles that can go about the same top speed. The one has less than a third of the horsepower of the other but is a full 3 seconds and 30mph faster in the quarter mile. Why? Because even with me on it and a full load of fuel it weighs less than 1/5th of the car but its torque is a quarter of it. If you were to factor all those other things that would add to its mass at speed the difference in weight would probably be closer to 1/8th that of the car and it's still rockin' the torque at 1/4th. I've had the car on 3 different tracks, road, autocross and dragstrip and would really like to do the same with my bike but it's unlikely to ever see any track of any sort because of all the special treatment a bike has to have to be allowed. I have had both up to similarly scary high speeds and the bike just flat gets there faster.

Just my mostly incoherent 2 pennies here.

 

[7HO]

@Dragonwhisky Weight isn't a factor in top speed but it is a factor in acceleration. Read my post 2 up from yours.

 

[BarbarianGoth]

As what others have said, to put it simply, horsepower (and aerodynamics) dictates a car's top speed. Torque is what gets it there. Lots of torque = lots of low end power and acceleration and (unfortunately) wheel spin.
Weight of a vehicle works in tandem with torque: low weight will amplify the effects of torque, and heavy weight will diminish it.

 

[Dragonwhisky]

@7HO , sure it does, but only when you include the shape of the mass and how much air that shape displaces as it accelerates in your "weight" value, otherwise known as aerodynamics. The faster you move any shape through the air the more torque, or perhaps thrust might be a better term, is required to move it faster. There will come a point at which the torque/thrust you have can no longer overcome the resistance the air presents to the shape you're moving and is part of the "weight" of that shape. If that Bloodhound doesn't fly apart before it reaches it, even it will likely find a point at which it can no longer accelerate. If there's enough room for it to get there anyway.

 

[Skygrasper550]

It seems it's more complex than I thought. because I initially thought torque = acceleration and horspower = top speed. Was gonna reply to the comments that quoted mine, but this turned into quite the discussion so I'm just gonna follow this thread for now.

 

[7HO]

@7HO , sure it does, but only when you include the shape of the mass and how much air that shape displaces as it accelerates in your "weight" value, otherwise known as aerodynamics. The faster you move any shape through the air the more torque, or perhaps thrust might be a better term, is required to move it faster. There will come a point at which the torque/thrust you have can no longer overcome the resistance the air presents to the shape you're moving and is part of the "weight" of that shape. If that Bloodhound doesn't fly apart before it reaches it, even it will likely find a point at which it can no longer accelerate. If there's enough room for it to get there anyway.

No this isn't correct. Weight isn't a factor in top speed, only in acceleration.

F=ma Since at top speed acceleration = 0 m*0=0 This means mass is irrelevant but not really because mass could effect rolling resistance and rolling resistance is a factor in top speed. But when we bring engineering into play we can reduce rolling resistance through engineering to the point where mass is again irrelevant. I'm sure you could find a Reddit discussion or an Engineering forum on this topic if you doubt what I just said.

 

[CSLACR]

Torque is a force applied at a distance from an axis, which would indeed induce rotation if free to do so. The crucial difference is that you can have torque without rotation, but you don't do any work if you don't move something.

Power is specifically energy per time, not rotational force per time, which doesn't really mean anything. In the typical calculation of the work done by applying a torque over a rotation, the distance aspect gets obscured thanks to imperial units - it is captured in the 5252 figure, follow the link for details:
http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm#equation

It is important to keep track of the speeds of things in order to properly assess power; torque can vary, but in thermodynamic terms, the total power must remain constant (IN = OUT).
By doubling the rotation speed, you double the distance per unit time, and hence double power output for a constant torque (force) output. Conversely, by doubling torque through gearing, you must consequently halve the output speed, and so power is unaffected.

That's my issue.
People say "gears multiply torque", and it implies and leads a lot of people to believe that you actually have more power* in lower gears than higher.
*A quick browse of this thread shows how many people think torque is some totally different animal than power, and have no concept of horsepower.

Furthermore, leaving the part out about moving half the speed leaves half of the equation off the table.
It's misleading at best.

It also implies that you have more "torque" in 1st gear than 2nd. By "torque", I mean an engine's output of a stroke.(like 350 ft-lbs turning into 700 with 2-1 gearing)((yes it kind of does, but the engine's output is still 350, and the speed is cut, so there isn't actually any extra power being delivered))

All in all, the saying just isn't really true, not completely. (because halving the speed negates the extra torque in terms of usable power.)
What gearing actually does, is change the speed(s) of which you have maximum usable power.

 

[Scaff]

That's my issue.
People say "gears multiply torque", and it implies and leads a lot of people to believe that you actually have more power* in lower gears than higher.
*A quick browse of this thread shows how many people think torque is some totally different animal than power, and have no concept of horsepower.

Only if you believe that torque and power are the same thing, which as has been repeatedly said they are not.

Furthermore, leaving the part out about moving half the speed leaves half of the equation off the table.
It's misleading at best.

Not as missleading as claiming that gear have no affect on output torque or attempting to suggest that people are claiming that it means the engine power will be changed!

It also implies that you have more "torque" in 1st gear than 2nd. By "torque", I mean an engine's output of a stroke.(like 350 ft-lbs turning into 700 with 2-1 gearing)((yes it kind of does, but the engine's output is still 350, and the speed is cut, so there isn't actually any extra power being delivered))

At the driven wheels you will, which is what everyone has been saying, what all the linked sources say.

Oh and once again power and torque are not the same.

All in all, the saying just isn't really true, not completely. (because halving the speed negates the extra torque in terms of usable power.)

No it doesn't.

Delivering more torque at a lower speed is exactly whats needed in lower gears, or your not going to be able to overcoming the rolling resistance of the tyres, or control the descent of a vehicle going downhill. Without gearing having this affect on the driven wheels you would never move any form of commercial vehicle, tractor or heavy plant machinery.

And less torque at higher speeds is required so you can reach a higher vehicle speed without obliterating the tyres in a cloud of smoke.

What gearing actually does, is change the speed(s) of which you have maximum usable power.

No it does both.

However you have spent pages attempting to say that it doesn't multiple torque, that gears are not force multipliers and attempting to say (inaccurately) that people were actually claiming it affected engine torque!

Quite frankly given how wrong you have been and some of the accusations you've leveled at people this is one of the most disingenuous posts I've seen in a very long time.

 

[CSLACR]

Only if you believe that torque and power are the same thing, which as has been repeatedly said they are not.

They are inevitably entwined in this case.

Not as missleading as claiming that gear have no affect on output torque or attempting to suggest that people are claiming that it means the engine power will be changed!

No, I say it's not really true, because it's worded poorly. Like I also said, it's only part of the equation.
Leaving half of an equation out is not what I call "accurate".

At the driven wheels you will, which is what everyone has been saying, what all the linked sources say.

Oh and once again power and torque are not the same.

Once again, half the equation is missing.
The claim of "more torque" implies more power, because torque and power are so strongly associated.

No it doesn't.

Delivering more torque at a lower speed is exactly whats needed in lower gears, or your not going to be able to overcoming the rolling resistance of the tyres, or control the descent of a vehicle going downhill. Without gearing having this affect on the driven wheels you would never move any form of commercial vehicle, tractor or heavy plant machinery.

That's based entirely on the structure of engines as we know them. There are absolutely other ways to move heavy things, though they may be more expensive, or less efficient.

And less torque at higher speeds is required so you can reach a higher vehicle speed without obliterating the tyres in a cloud of smoke.

Oh, I had no idea you could possibly reach high speeds in a quick gear, even if you wanted to. Must be a 50k rpm motor.

No it does both.

However you have spent pages attempting to say that it doesn't multiple torque, that gears are not force multipliers and attempting to say (inaccurately) that people were actually claiming it affected engine torque!

It doesn't multiply the total torque output, it multiplies the torque output at the cost of reducing speed, leaving the total applied torque, identical.

Quite frankly given how wrong you have been and some of the accusations you've leveled at people this is one of the most disingenuous posts I've seen in a very long time.

I "leveled accusations"?
I don't recall.

And yes, it does matter if a saying misleads most people, that's what defines a good saying, and a bad one.
A saying that misleads most people (be it through lack of understand or anything else) leads to the majority of people thinking something untrue. How's that good?

The reason(s) gearing is needed, is because engine's spin too fast to be making power (yes, power, really) at low speeds.
An engine running 1-1 gearing that reaches 30mph, will move exactly as well as an engine that reaches 30mph with 4-1 gearing.

Gears are need for both, having power (yep, power) at low speeds, and also being able to go past certain speeds, and of course, fuel mileage.
You can't set a car up with 1-1 gearing that reaches 30mph without gears, because it would suck at driving, with a top speed of 30mph. On the opposite side, you can't set an engine stuck in a 1-1 gear that reaches 120mph, because you won't have any (yes, power) at low speeds.

The entire thing is a semantic, based on the fact that engines spin so quickly a 1-1 ratio is useless at low speeds.
If it wasn't, you'd be arguing that gearing multiplies speed, and we wouldn't be talking about torque at all.(because that's all most gears would be used for, if engines reached 20-30mph @1-1 ratios)

 

[Tekku]

Just got the LaFerraria and the torque for this car is unreal. Whenever you put your foot on the gas pedal it feels like you're starting up a jet and is about to take off.

 

[CSLACR]

There's another one mislead by all the torque-talk.
What a good saying.

 

[Scaff]

They are inevitably entwined in this case.

But not the same.

No, I say it's not really true, because it's worded poorly. Like I also said, it's only part of the equation.
Leaving half of an equation out is not what I call "accurate".

What's the si unit for torque?

Once again, half the equation is missing.
The claim of "more torque" implies more power, because torque and power are so strongly associated.

No that's something that you are infering.

I've never implied it once, in fact I've been quite clear in pointing out that's not the case.

That's based entirely on the structure of engines as we know them. There are absolutely other ways to move heavy things, though they may be more expensive, or less efficient.

Good job were talking about ICE's then.

It doesn't multiply the total torque output, it multiplies the torque output at the cost of reducing speed, leaving the total applied torque, identical.

Torque is not a measure of speed, speed is not a factor in the value of torque.

Torque can be delivered at differing speeds and that is a part of gearing, but the two are not the same value or the same measure.

The si value of torque is nM, with kgm and ftlb also being commonly used, no part of that value is time or speed based.

Nor is speed or time a value in the formula to derive torque, which is

T = r x F
t = ||r||F||sin o

where

T is the torque vector and T is the magnitude of the torque,
r is the position vector
F is the force vector,
o is the angle between the force vector and the lever arm vector.
None of which are time or speed based.

I "leveled accusations"?
I don't recall.

Quite a few.

And yes, it does matter if a saying misleads most people, that's what defines a good saying, and a bad one.
A saying that misleads most people (be it through lack of understand or anything else) leads to the majority of people thinking something untrue. How's that good?

No its not.

Gearing is a force multiplier, that is a fact.

To overcome the rolling resistance of a tyre sufficient force needs to be applied to it, how quickly that force is delivered is not the issue, its that sufficient force is delivered to overcome the rolling resistance, particularly from a standstill, with requires a singnificant degree more force than to keep a tyre rolling.

A rolling tyre on a 1,400 kilo car would need around 100N per tyre of force to applied just to keep it moving (so 400 for the entire car - roughly 100lbs of force), however if its stationary that is going to increase by at least 200 to 400% per tyre depending on the slip percentage the tyre generates.

A 44,000 kilo truck with six axles would have a total of 12 tyres and require at least 4,400N per tyre, so 52,800N just to keep moving, which is around 13,200 lbs of force.

If torque was effectively unchanged because its being delivered more slowly you would struggle to get even a light unladen car moving, let alone a fully loaded HGV.

Gearing multiples force, it also delivers it more slowly, but they do not cancel each other out to leave the force unchanged because they are two different measures.

The reason(s) gearing is needed, is because engine's spin too fast to be making power (yes, power, really) at low speeds.
An engine running 1-1 gearing that reaches 30mph, will move exactly as well as an engine that reaches 30mph with 4-1 gearing.

Torque and power - still not the same.

You see the only person conflating these repeatedly is you.

Gears are need for both, having power (yep, power) at low speeds, and also being able to go past certain speeds, and of course, fuel mileage.
You can't set a car up with 1-1 gearing that reaches 30mph without gears, because it would suck at driving, with a top speed of 30mph. On the opposite side, you can't set an engine stuck in a 1-1 gear that reaches 120mph, because you won't have any (yes, power) at low speeds.

Gears don't multiply power, they multiple force, because power and force are still not the same thing.

The entire thing is a semantic, based on the fact that engines spin so quickly a 1-1 ratio is useless at low speeds.
If it wasn't, you'd be arguing that gearing multiplies speed, and we wouldn't be talking about torque at all.(because that's all most gears would be used for, if engines reached 20-30mph @1-1 ratios)

No its really not semantics.

Power is not force. They are related but not the same thing.

Gearing is a force multiplier, gearing also changes how quickly force is applied, but they do not cancel each other out to result in the same level of force as was input, as they are two different measures. were they not then the SI and way in which we calculate force would have a speed or time element, it doesn't.

If what you are claiming were true gears would not work, levels would not work, pulleys would not work.

 

[Vegard]

@CSLACR I think you're confusing ft lb for lb ft.

The foot-pound is a unit of work/energy while the pound-foot is a measure of torque.

 

[CSLACR]

No that's something that you are infering.

I've never implied it once, in fact I've been quite clear in pointing out that's not the case.

No, I'm saying the common statement (which isn't yours, you're repeating it, and no that isn't a jab) "gears multiply torque" leads most people to believe that "torque" (the single stroke) is more important for acceleration than torque X speed.(horsepower)

Good job were talking about ICE's then.

You could do it with an ICE.

Torque is not a measure of speed, speed is not a factor in the value of torque.

Torque can be delivered at differing speeds and that is a part of gearing, but the two are not the same value or the same measure.

The si value of torque is nM, with kgm and ftlb also being commonly used, no part of that value is time or speed based.

Nor is speed or time a value in the formula to derive torque, which is

T = r x F
t = ||r||F||sin o

where

T is the torque vector and T is the magnitude of the torque,
r is the position vector
F is the force vector,
o is the angle between the force vector and the lever arm vector.
None of which are time or speed based.

I understand that, I am not arguing it.
What I am saying, is that cars are driven by torque X speed, and not torque alone. When multiplying torque divides speed, in the case of ICE's, it cancels itself out.

I know quite a few people that truly believe, and cannot be convinced otherwise, that you actually have more total driving force at the wheels in lower gears, because of this saying.
They also believe that you shift around your peak torque for maximum acceleration, because of this saying.

Quite a few.

I don't know what I said specifically, but I like you Scaff, I really do. You're smart and I respect your intelligence. Don't let my attitude make you think otherwise, I'm just an ass sometimes.

No its not.

Gearing is a force multiplier, that is a fact.

To overcome the rolling resistance of a tyre sufficient force needs to be applied to it, how quickly that force is delivered is not the issue, its that sufficient force is delivered to overcome the rolling resistance, particularly from a standstill, with requires a singnificant degree more force than to keep a tyre rolling.

A rolling tyre on a 1,400 kilo car would need around 100N per tyre of force to applied just to keep it moving (so 400 for the entire car - roughly 100lbs of force), however if its stationary that is going to increase by at least 200 to 400% per tyre depending on the slip percentage the tyre generates.

A 44,000 kilo truck with six axles would have a total of 12 tyres and require at least 4,400N per tyre, so 52,800N just to keep moving, which is around 13,200 lbs of force.

If torque was effectively unchanged because its being delivered more slowly you would struggle to get even a light unladen car moving, let alone a fully loaded HGV.

Gearing multiples force, it also delivers it more slowly, but they do not cancel each other out to leave the force unchanged because they are two different measures.

Unless you're saying that a vehicle with a 1-1 ratio that reaches 30mph would be slower than the same vehicle, using a 4-1 gear to reach 30mph, we're not disagreeing.
They'll both be at the same rpm, the entire time, and they'll both make the same amount of driving force at the wheels. One will do it by multiplying torque and dividing speed, the other will do it with the engine's exact torque and speed.

Torque and power - still not the same.

You see the only person conflating these repeatedly is you.

Have you not read a single one of the totally incorrect posts in this thread?
I would argue that quite a substantial amount of people conflate the two, particularly because of blanket statements like "gears multiply torque". (don't forget "torque wins races" and "torque is how far you move the wall" and "torque is what you can tow")

And if we get really picky, some gears keep torque exact, and yet more actually decrease torque.

Gears don't multiply power, they multiple force, because power and force are still not the same thing.

They multiply force, by dividing speed.
Driving force is comprised of both.
How can you not see that it's leaving half the equation out?

No its really not semantics.

Power is not force. They are related but not the same thing.

But power is what moves the vehicle down the road. The engine already has speed at idle. Even with a 500rpm idle and 5-1 gears, that torque is being multiplied with speed by more than 1.5x per second.

Gearing is a force multiplier, gearing also changes how quickly force is applied, but they do not cancel each other out to result in the same level of force as was input, as they are two different measures. were they not then the SI and way in which we calculate force would have a speed or time element, it doesn't.

If what you are claiming were true gears would not work, levels would not work, pulleys would not work.

I'm saying that 300 x 100 equals the same as 100 x 300.
If changing 300 to 100 requires 100 to change to 300, there is no difference.(at least in the case of power applied from an engine)

Likewise, an engine making 300lb of torque and 300hp, isn't more powerful than an engine making 200lb and 300hp. When the engine is at the same power level, the car accelerates the same.
I understand that torque and power are not the same, but it equals the same power, and power is what drives the vehicle.

It doesn't make the engine have more driving force, and that's how it's generally perceived, even on the internet.

@CSLACR I think you're confusing ft lb for lb ft.

The foot-pound is a unit of work/energy while the pound-foot is a measure of torque.

Not really, I get those things backwards too much to bother, kind of like toe in and out. I probably have a few posts where I used both, for absolutely no reason.

 

[MightyL]

To pull the whole discussion back to the game: in cockpit view, the drivers hand shifting animation is activated at a certain point through the revs. Even if you are not yet gearing up or down. Because the point at which the animation starts is different fr every car n even what gear you are in, I always thought that was GTs personal view on what wd be the best point for changing gears considering the torque and power curve.
But in doing the very first driving school test i noticed, at least for the mx-5, that is not the case...
We really need some podi ingeneer explaining how they implemented torque n power curves in GTS

 

[dudejo]

I know this is an old topic but I think I have something worthwhile to add.

If gear ratios don't multiply torque, why do certain axle application guides specify input or output torque limits that are WAY beyond anything a production engine could generate?

For example, the Dana 44 axle, used in the Dodge Viper among others, is rated for ~4,500 ft/lb of output torque. Obviously, no production car engine on earth will generate that much.

As for the general question of Horsepower vs Torque, my opinion is that torque is mostly a factor when launching in 1st gear. Having more torque means either more kick off the line or a higher top speed with the same acceleration, all depending on your gear ratio. After that, you're going fast enough that you can simply maintain your RPMs at peak horsepower by changing gears.