The Torque Thread. And other little things you might find useful...
- Thread starter yannagas
- 107 comments
- 48,055 views
- 31
- United States
To be clear your talking about peak numbers only?
The limiter is reducing both horsepower AND torque at a given rpm. The reason peak torque stays the same is because it happens at a lower Rpm. The limiter is like cutting the top off two mountain, one being shorter than the other, torque mountain is not going to get any shorter until youve cut enough off hp mountian to reach the same height.
- 10,456
- United States
- WrecklessAbandon
Anyone discussing "individual merits" of "torque and power" already doesn't understand the concept.
It's a shame we can't mathematically make a formula, something like torque per minute, or torque per second. That would solve everything, or so you would think...
Sarcasm aside, I really wish auto manufactures would start advertising torque per second. That sure would make people angry and confused...
It's also a more accurate depiction of power applied.
It's a shame we can't mathematically make a formula, something like torque per minute, or torque per second. That would solve everything, or so you would think...
Sarcasm aside, I really wish auto manufactures would start advertising torque per second. That sure would make people angry and confused...
It's also a more accurate depiction of power applied.
- 11,252
- Sweden
- eran0004
Just to give some additional insight into the mystery of torque and power:
Q: Why is more power always going to perform better than more torque?
A: Because more power is even more torque than more torque.
That doesn't even make sense! How does that work?
This is a basic formula for power:
Power = torque * speed
Which gives that:
Torque = power / speed
Which gives the following graph plotting wheel torque at various speeds for two different cars, where the red line is the wheel torque for the car with more power, while the blue line is the wheel torque for the car with more torque (assuming a CVT transmission or some other similar device that allows the engine to operate at peak power at all times, alternatively one can assume that both engines have very flat power curves and enough gears to run at peak power at all speeds).
Red = more power
Blue = more torque
And since acceleration = force / mass and if we say that the mass is equal for both cars, then the graph also shows the acceleration of both cars. Again, the red car is always accelerating at a faster rate than the blue car.
Which also busts this quote from the first page:
Either they didn't say that, or they didn't know what they were talking about when they said it. Torque is only useful if it occurs at a speed, and the higher the speed, the more useful it becomes - the greater its effect, its power. Thus, power is a measure of the effect of torque. Lots of torque but little power only means that you have a lot of lazy torque, and that's not going to win any race for you.
Also, this:
... is almost correct, but not quite. Power is torque * distance / time (or torque * speed).
1 Joule is one Newton meter, that's correct, but not as a measure of torque, as a measure of energy. Energy and torque are two completely different things. The Nm (energy) is defined as a force of one Newton acting over a distance of one meter. The Nm (torque) is defined as a force of one Newton acting on a distance of one meter from the center of rotation. In the first case (energy) the force has covered a distance. In the second case (torque) the force has not covered any distance. The SI unit of energy is Joule, because they want to avoid this confusion of Nm (energy) with Nm (torque).
Q: Why is more power always going to perform better than more torque?
A: Because more power is even more torque than more torque.
That doesn't even make sense! How does that work?
This is a basic formula for power:
Power = torque * speed
Which gives that:
Torque = power / speed
Which gives the following graph plotting wheel torque at various speeds for two different cars, where the red line is the wheel torque for the car with more power, while the blue line is the wheel torque for the car with more torque (assuming a CVT transmission or some other similar device that allows the engine to operate at peak power at all times, alternatively one can assume that both engines have very flat power curves and enough gears to run at peak power at all speeds).
Red = more power
Blue = more torque
And since acceleration = force / mass and if we say that the mass is equal for both cars, then the graph also shows the acceleration of both cars. Again, the red car is always accelerating at a faster rate than the blue car.
Which also busts this quote from the first page:
Either they didn't say that, or they didn't know what they were talking about when they said it. Torque is only useful if it occurs at a speed, and the higher the speed, the more useful it becomes - the greater its effect, its power. Thus, power is a measure of the effect of torque. Lots of torque but little power only means that you have a lot of lazy torque, and that's not going to win any race for you.
Also, this:
... is almost correct, but not quite. Power is torque * distance / time (or torque * speed).
1 Joule is one Newton meter, that's correct, but not as a measure of torque, as a measure of energy. Energy and torque are two completely different things. The Nm (energy) is defined as a force of one Newton acting over a distance of one meter. The Nm (torque) is defined as a force of one Newton acting on a distance of one meter from the center of rotation. In the first case (energy) the force has covered a distance. In the second case (torque) the force has not covered any distance. The SI unit of energy is Joule, because they want to avoid this confusion of Nm (energy) with Nm (torque).
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Take a car like the x bow, and it has a torque and power curve like what is shown in black. If you were able to increase torque without increasing (peak) horsepower, you would get a curve like the green curve. If you were able to increase horsepower without increasing peak torque, you get a curve like the red one.
You would get no performance gain across almost the entire RPM range from increasing just peak horsepower.
By tuning a car without increasing RPM where peak torque or peak horsepower occur, you have a performance increase like the green line on the graph.
The tuning options that increase RPM still boost peak torque, so you still can get some boost to performance, these options are like a hybrid between the red and green lines on the graph.
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- 14
- whitepanther65
Hi, very interesting thread. But I have never seen in any place a discussion on how gears should be chosen in order to get maximum mean acceleration. In GT6 or real life, for that matter...
- 5,489
- mid west USA
- Otaliema
Non Drag-Racing Transmission Tuning Guide is a good place to start. In the guide there is a link to the 1/4 mile guide as well.
In particular read the section on acceleration builds and how to set them up, In general they will be 1-5 km/h faster than normal builds.
- 14
- whitepanther65
Oh thanks Otaliema, I had missed that one. However it is way too complicated for me. And it doesn't answer to basic questions. For instance, why not choose gears in fixed ratios (first/second=second/third and so on)? That what would seem a reasonable choice in order to keep the engine always in a high torque range. However gt6 doesnt make this choice: the ratio between fifth and sixth is smaller than the ratio between first and second. Or, higher gears are shorter than lower gears if you prefer. Why?
- 5,489
- mid west USA
- Otaliema
The pure technical stuff I'm not sure to be honest. The guide covers how to build transmissions to put the cars power to the best use and get the most mechanical advantage from it.
PD choose to set ratios based RPM to keep cars top speed the same regardless of the engine setup. Real setups can be very effective as shown by replica builders such as @Ridox2JZGTE cars. How ever the gaming the game set ups as covered by @Master__Shake_ 1/4 mile and my non drag racing guides will always be faster than a replica transmission.
- 1,835
- New york
- IvIaster__Shake_
I wholly believe that torque multiplication isn't calculated properly in this game or skewed somewhat, and therefore cannot be put onto the track as with racing in real life. Most transmisions that I've created in this game use extended first and second gears to simulate added grip, when in reality they're using the gearing itself to mildly bog the RPMs to the point of maximum torque so the tires will bite harder than simply spinning and hitting the rev-limiter. After that, once you achieve certain speeds(mainly above 100mph), it's important to keep the following gears tighter to achieve maximum acceleration.
The game seems to want you to upshift as fast as possible through peak horsepower, even though logic would dictate that staying in the torque band would provide better acceleration for the majority of the gear. 5th and 6th gears, especially in cars hitting 200mph+ on a long track, are harder to adjust because changing them without adjusting previous gears will cause sluggish acceleration or none at all - once again, the car wants to be at peak horsepower range and very rarely prefers the torque band(diesel or mid turbo setup mostly). In the end, it's a game and I tried not to let realism or lack thereof ruin it for me.
Some replica transmissions are actually great for track and drag racing. A group of my friends used to do 'realistic' drag nights with replica muscle cars, and the M21/M22 transmission seemed great for cars under 450 horsepower. I assume there's racing transmissions that can run closely with optimized setups.
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- 14
- whitepanther65
Sorry guys, I don't understand most of the terms you use like "ratios based RPM", "engine setup","torque multiplication", "mildly bog" and so on; therefore it's hard for me to follow what you're saying. However, I'm convinced that things must be simpler than that. It occured to me that air resistance increases a lot with velocity (proportional to v^2 if I remember well). This is a very good reason for choosing higher gears shorter than lower gears if you want constant acceleration!
- 1,485
- Hampshire
- Lionheart2113
I might not understand all of physics about it, but I agree with your end result. Below is a picture from the recent FITT challenge and the custom transmission I created. It shows what the RPMs drop down to after every shift. This transmission was different because it had to use the same gears no matter what the PP level/added Power Parts were.
Blue = 565pp with all parts added (8,500RPM @ redline)
Black = 465pp with no parts added (7,900RPM @ redline)
You can see that the gears 3-5 were in the higher RPM range after their respective shifts to keep the momentum while the lower gears are spaced in a way trying to avoid dropping down into 1st gear on slow corners, but not bog you down when you hit the gas getting up to that 100mph point.
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- 5,489
- mid west USA
- Otaliema
Sorry fell into jargon speak.
RPM based ratios.
Take ANY car that can upgrade, the engine, computer, exhaust, or Catalytic converter. (basically any street car)
Take note of 1st gear.
Install one of the above mentioned upgrades.
Reset defaults on the transmission. The number will change.
Compared to real life were the car would use the new increase in RPM to gain speed, PD made the transmissions based on a particular speed, eg 240 km/h so the game changes the transmission numbers to meet that speed when the RPM's change in the engine.
Bog; To fall out of the main power band, the acceleration decreases until the RPM's reach the power band again.
Bog is used on high powered cars or hard tires to reduce wheel spin.
You are correct the faster you go the more drag and resistance you get until 250 km/h than it changes and goes down. o_O, PD attempting to placate the minority but very vocal group of people that complained the top speed of the cars was too low.
As for torque conversion, the transmission on the car has two jobs when it's all said and done.
Reduce high RPM's from the engine to lower RPM's for the wheels and multiply the torque being generated by the engine.
((Torque*Gear Ratio)*Final Ratio)*0.85 IIRC so say take a Volvo 240 GLT Estate '88
272 ft-lbs
first gear of 4.192
Final of 2.500
272*4.192=1140.224
1140.224*2.5=2850.56
2850.56*.85=2422.976
2850.56 ft-lbs being delivered to the drive wheels in a perfect world. But friction need to be accounted for, lets assume they put in the accepted loss of 15% so we are only getting 85% of that number.
2850.56*.85=2422.976 ft-lbs to drive the car in first gear.
check that to the weight
1602 kg = 3532.41 lbs (1 kg = 2.205 lbs)
So the car is making 1109.434 ft-lbs less torque then weight. And it shows in the game the car is sluggish! And this is a fully upgraded car too
The better the ratios the better the acceleration, but also remember it takes more power to get the car moving, than to keep it moving. So the higher gears can generate far less torque and still make the car go forward, provided the gear keeps the engine at or after peak torque generation.
if you ever get curious, HP is calculated RPM*torque/5252, so you can get you torque at peak power in game by HP*5252/RPM.
There is lots of fancy maths you can do to find out the rest of it by using wheel speed, but try as I might I never quite got it even with help from @Lionheart2113 and @OdeFinn it flew right over my head.
- 1,835
- New york
- IvIaster__Shake_
I mostly did the same thing when I customized my transmissions, except my 1st gear was roughly where your 2nd is. Even though it put me into lower RPMs at low speeds, it let me use longer gearing for 200mph+ tracks. That also allowed me to keep ratios close so engine speed never dropped more than 1500 under peak horsepower, which relates to maximum acceleration. It was especially useful on tracks that had long straightaways to hit 230-250mph.
It really makes me wish I could still play; not having a real racing game is like having a void I can't fill.
- 1,485
- Hampshire
- Lionheart2113
You're right about trying to run the gears to hit higher top speeds, but this was a '91 RX-7, 250mph wasn't going to be an issue!
Usually I take a car out to the ring, turn it around and head down the long straight (going the wrong way). I see what mph it can get up to at the end of it...say 180mph. That is my new target for max speed @ redline in the highest gear. That should keep you safe for any track and its longest straight. Plus with it only being max speed at redline, that should also help if you are drafting as the highest gear takes you over the redline point before cutting out.
- 1,835
- New york
- IvIaster__Shake_
I normally gave myself 20 or 25 MPH extra for drafting, more on race cars with 750hp+. It starts getting tricky on cars with peak horsepower a couple thousand below the rev-limiter or redline. I remember the Escudo being one of the hardest to tune because of the narrow powerband.You're right about trying to run the gears to hit higher top speeds, but this was a '91 RX-7, 250mph wasn't going to be an issue!
Usually I take a car out to the ring, turn it around and head down the long straight (going the wrong way). I see what mph it can get up to at the end of it...say 180mph. That is my new target for max speed @ redline in the highest gear. That should keep you safe for any track and its longest straight. Plus with it only being max speed at redline, that should also help if you are drafting as the highest gear takes you over the redline point before cutting out.
- 14
- whitepanther65
Very interesting, didn't know that. This means that the game takes into account the change in the torque vs RPM curve due to upgrades, right? What is PD, btw?
Ah ok thanks. So thats what I try to do when I have a high power car whose wheels spin like crazy at the start of a race.
You are correct the faster you go the more drag and resistance you get until 250 km/h than it changes and goes down. o_O, PD attempting to placate the minority but very vocal group of people that complained the top speed of the cars was too low.
As for torque conversion, the transmission on the car has two jobs when it's all said and done.
Reduce high RPM's from the engine to lower RPM's for the wheels and multiply the torque being generated by the engine.
((Torque*Gear Ratio)*Final Ratio)*0.85 IIRC so say take a Volvo 240 GLT Estate '88
272 ft-lbs
first gear of 4.192
Final of 2.500
272*4.192=1140.224
1140.224*2.5=2850.56
2850.56*.85=2422.976
2850.56 ft-lbs being delivered to the drive wheels in a perfect world. But friction need to be accounted for, lets assume they put in the accepted loss of 15% so we are only getting 85% of that number.
2850.56*.85=2422.976 ft-lbs to drive the car in first gear.
check that to the weight
1602 kg = 3532.41 lbs (1 kg = 2.205 lbs)
So the car is making 1109.434 ft-lbs less torque then weight. And it shows in the game the car is sluggish! And this is a fully upgraded car too
The better the ratios the better the acceleration, but also remember it takes more power to get the car moving, than to keep it moving. So the higher gears can generate far less torque and still make the car go forward, provided the gear keeps the engine at or after peak torque generation.
if you ever get curious, HP is calculated RPM*torque/5252, so you can get you torque at peak power in game by HP*5252/RPM.
There is lots of fancy maths you can do to find out the rest of it by using wheel speed, but try as I might I never quite got it even with help from @Lionheart2113 and @OdeFinn it flew right over my head.
Ok Otaliema, this looks all very sound to me. Yet, my initial question is still unanswered: How should gear ratios be chosen? I would like to have a formula or something in order to do that. Otherwise, I will keep on stickig to GT6's values.
- 5,489
- mid west USA
- Otaliema
Well imo there is no magic formula for picking gears. What are you after with the car, speed acceleration, smoothness? These and other factors play into the gears used in the transmission.
It's literally just experience and trial and error to know/find out what a car will like.
Some tuners like @shaunm80 and @Lionheart2113 use a % of the slider and vary it a touch based on the power band of the car in use.
Your suspension comes into play as well stiff cars and hard tired need smoother set ups softer cars with softer tires can get sharper set ups.
If you want to use a formula type approach go with what lionheart or shaunm do. It produces very good set ups. If you want to experiment read my transmission guide and experiment, practice and takes notes.
- 14
- whitepanther65
You're right, I didnt specify
. The problem I face is the following: I tune last gear for maximum speed in a given circuit. But then tipically, at least for FR and MR cars, my tyres spin a lot at the start of a race. Then, I choose a longer first gear until the wheels dont spin anymore. Ok. But I face a new problem: gears aren't evenly spaced anymore and in particular the second gear can be so close to the first that it becomes ridiculous. So, how to evenly space gears again? I tried visually, but it's a nightmare. And I must say I don't understand the methods involving "25 % of the slider" and so on that seem to be popular: it's a kind of magic formula for me and I don't understand the logic.Now, I still believe it musn't be that complicated. After all, the transmission trasmits the engine power to the wheels (ignoring some power loss) and at a given velocity, the force that causes the acceleration is proportional to the power.....that's it! So, if it weren't for air drag, i would simply choose gears in such a way that the motor is always in high power regime. Therefore I would choose gear ratios to be constant (geometric series). But, there IS air drag and I get lost....
- 1,485
- Hampshire
- Lionheart2113
@whitepanther65 How good are your Excel skills? I have created a sheet that will help compare up to 4 transmissions at a time(6 gear transmission only so far) and it would assist you with the "25% slider" scenarios.
Or if someone could tell me how to share it for the community, and I could provide a walkthrough vid/pics on how to use it. I know google docs allow the easiest sharing, but last I checked I would lose the graph.
Or if someone could tell me how to share it for the community, and I could provide a walkthrough vid/pics on how to use it. I know google docs allow the easiest sharing, but last I checked I would lose the graph.
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