Understanding 'Power Band' and tuning transmission gears accordingly

  • Thread starter LanaBunny
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LanaBunny

LanaBunny

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LanaBunny

Hello gt-planet,

I've searched all over this forum in an effort to find some information about this subject but haven't found what I'm looking for. I'm currently racing in a 500pp league at Nurburgring 24hr on sports hards tires. The fastest cars all seem to be 4wd some of them setting laps in the 9:20 range! For example, the fastest cars tend to be Audis (TTS, RS6 Avant, S4, etc.) and one of the fastest, shockingly enough, the Dodge Ram (also 4wd). These cars are heavy and I'm quite proffecient at tuning their suspensions and drivetrains but I'm lacking in the gearing department.

I have a broad question about the 'Power Band' or 'Power Curve' represented on a graph in your tuning settings: a yellow and green line with an intersection point showing max rpm torque and max power (hp). I know how to set up the gear box properly - set top speed to the far left and final gear to the far right. Then adjust gear sizes to your desired shape and move the final gear back to the left until you've reached optimal top speed (not forgetting to tune that about 10mph or 15khm higher due to drag). I can give some examples of different power curves if you ask but I'm wondering is their a car with a better power band shape? What would this look like? Can any car be tuned to be in the power band at all times? Heavilly limited cars often have a really steep line at the beginning and it drops off. Other kinds of lines can be steep all the way up to the end some are somwhere in the middle. Where is the area of power and how should I shape the gears?
 
The most extreme example of a car with mid rpm power and tall gears I have tuned is Cuda 440 six pack. I set final gear with the maximum value and then the max speed at maximum. I then lowered the final drive ratio to increase the indicated maximum speed even higher.

I was just trying to get the car to the highest max speed on the straight at Nurburgring and with some testing I found I needed to have the rpm sitting about where max power was at the end of the straight (5500rpm). The gears were all very tall and very spaced and the indicated max speed was very, very, very high.

Then I adjusted the lower gears so I would shift at 6000prm in third, drop to 5000rpm in fourth and shift into 5th at 6000rpm again.
 
MrGrado
The most extreme example of a car with mid rpm power and tall gears I have tuned is Cuda 440 six pack. I set final gear with the maximum value and then the max speed at maximum. I then lowered the final drive ratio to increase the indicated maximum speed even higher.

I was just trying to get the car to the highest max speed on the straight at Nurburgring and with some testing I found I needed to have the rpm sitting about where max power was at the end of the straight (5500rpm). The gears were all very tall and very spaced and the indicated max speed was very, very, very high.

Then I adjusted the lower gears so I would shift at 6000prm in third, drop to 5000rpm in fourth and shift into 5th at 6000rpm again.
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Im confused as to what you mean by tall gears? Do you mean that when you edited the gears you moved them all to the left or the right?

Another thing, were you shifting early to stay in the power band? How much higher was the indicated speed than the speed you actually reached in the end of the straight?
 
A tall gear gear is right, short gear is low. I believe he was referring to shifting early. I have no experience like this but I can give you a example. If you take a look at my Honda NSX Type S '01 I listed the approximate gear at which it will shift which is 6500RPMs. You will also notice my gearing is odd as I primarily only use 5 gears. The first 4 gears I tried to keep within the 6500RPMs as those were the gears I was usually in, 5th and 6th were a bit taller, and 6th was only used for drafting on Nurburg. https://www.gtplanet.net/forum/showthread.php?t=224513
 
Master_gamer438
A tall gear gear is right, short gear is low. I believe he was referring to shifting early. I have no experience like this but I can give you a example. If you take a look at my Honda NSX Type S '01 I listed the approximate gear at which it will shift which is 6500RPMs. You will also notice my gearing is odd as I primarily only use 5 gears. The first 4 gears I tried to keep within the 6500RPMs as those were the gears I was usually in, 5th and 6th were a bit taller, and 6th was only used for drafting on Nurburg. https://www.gtplanet.net/forum/showthread.php?t=224513
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No. A tall gear is a long gear, and long is to the left.

OP - Pay no real mind to torque, horsepower is the calculation that will make your car go, and nothing else.
The flatter the HP curve towards the top, the better.
 
My mistake, CSL correct, my PS3 laser died so havent played since Nov. But my new laser should be here for New Years. Smaller number(left) gives more speed, Higher number(right) better accel. If your car say max torque is 7000RPMs, and say you shift into a gear and RPMs drop to 6000RPMs, moving that gear right will get you closer to thar RPM. If you shift and say its 7500RPMs you would take the gear left to get more speed dropping the RPMs. I never like really noticed a crazy lap time difference by keeping car in optimum RPM range but as long as it's fairly close your golden.
 
Of course if you're shifting at peak torque you've already gone terribly wrong.
Torque = One single stroke, strokes per minute not factored in.
HP = Torque per minute.

The higher your torque per minute the faster you go.
 
CSLACR
Of course if you're shifting at peak torque you've already gone terribly wrong.
Torque = One single stroke, strokes per minute not factored in.
HP = Torque per minute.

The higher your torque per minute the faster you go.
Click to expand...

I dont think its that simple. Torque is the amount of force rotating around an axis if i remember the definition. So if you are going very fast with lots of wind resistance you really do want lots of torque top end so you can push through the drag. in real life at least
edit:
torque2.gif
 
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So its better to go with max HP at whatever RPM? Not max torque at its peak RPM? I always thought along the lines the guy said about pushing through the wind resistance with more torque would be better. although of course on the longest straight you want to be almost redlining but isint that the reason the car starts to slow down. Such as NASCARS even near peak redline at Daytona struggle like crazy once above 215MPH at 8000RPM, but when you have your cars RPMs drop near peak torque through corners I actually hold speed and can even gain speed in the corners which is very hard to do at Daytona. The closer I am to the torque line RPM it feels like the car is supercharged and flys through the speedometer. May have to try it through it through peak HP/RPMs.
 
I also prioritize HP over torque as it seems to be faster.

If upgrading the engine and optimizing for PP regulations, I always use the engine upgrade giving more HP rather than more torque. As an example. an engine stage upgrade gives more HP and less torque compared to a turbo. At the eame PP, I'm faster with an engine stage upgrade than an added turbo.

I alos try to get a flat powerband within the revolutions that I'm using. In most cases I try to a get flat powerband within a 1000 rpm range but no more. This will optimize available HP/PP. If the flat powerband is too big, the car will get to much torque and you will pay a PP penalty
 
Very interesting.

And it moves me to ask this question of Sail IC, CSLACR & ALL;

If creating cars for 450 to 500 PP races, is it better to build the car to match the pp as close you can? Or do you build ENG 3 and back off the power?:confused:

💡

My thought is you need to build the car close to the pp you are going to race it at to avoid using less than 95% of engine power.

When racing the "Ring" it's hard to figure power band with 450 PP cars. Always run out of gears on the back straight. At least I do.:ouch:
 
Master_gamer438
So its better to go with max HP at whatever RPM? Not max torque at its peak RPM? I always thought along the lines the guy said about pushing through the wind resistance with more torque would be better. although of course on the longest straight you want to be almost redlining but isint that the reason the car starts to slow down. Such as NASCARS even near peak redline at Daytona struggle like crazy once above 215MPH at 8000RPM, but when you have your cars RPMs drop near peak torque through corners I actually hold speed and can even gain speed in the corners which is very hard to do at Daytona. The closer I am to the torque line RPM it feels like the car is supercharged and flys through the speedometer. May have to try it through it through peak HP/RPMs.
Click to expand...

Torque is the power of one single engine stroke. But your engine doesn't ever do just one single stroke does it? If it only did one stroke, you'd move a couple feet and stop.
Ever wonder what 200 foot pounds of torque at 5000rpm actually equals in terms of driving force?
The answer is horsepower. Horsepower tells you how many foot pounds of torque your car is actually using when you factor in how many revolutions your engine is turning.

More torque is always a good thing, because torque translates into horsepower. Having more horsepower doesn't always mean more torque though, it can mean more revolutions.
If you punch a bag 2,000 times every minute with 100 pounds of force, it's exactly the same amount of force as punching it 4,000 times every minute with 50 pounds of force.
That total number - 2,000 X 100, or 4,000 X 50, (200,000) is horsepower.

200,000 divided by 5252 = 38 HP. Both examples have 38 horsepower, and both will accelerate exactly the same at that engine speed(RPM), and both will have exactly the same top speed at that RPM.

My thought is you need to build the car close to the pp you are going to race it at to avoid using less than 95% of engine power.
Click to expand...
Generally speaking around 94-99% power limiter is the best for PP racing.
But that's based on the game's system, and has nothing to do with how torque and horsepower relate in real life.

The game doesn't factor in the hp/torque relation properly, if it did, it wouldn't matter how much power limiter you used, because it would factor that in properly. The way the game is set, you might believe having oodles of torque in low RPM would make your car faster around a track, but since you don't race at 40% of red line, the amount of power you have at 40% of red line is irrelevant.
 
CSLACR
Generally speaking around 94-99% power limiter is the best for PP racing.
But that's based on the game's system, and has nothing to do with how torque and horsepower relate in real life.

The game doesn't factor in the hp/torque relation properly, if it did, it wouldn't matter how much power limiter you used, because it would factor that in properly.
Click to expand...


Thank you "CSLACR" that is information I was looking for.👍
 
Torque helps acceleration while HP determines your top speed. In theory, you'll get the best acceleration if you get your gears so that your next gear falls just before the rpm where torque curve meets the HP curve. The problem with this though is that you end up with a very narrow powerband in each gear so ideally, the next gear should catch the rpm between max torque and the point I mentioned above.

Although this doesn't necessarily translate directly to faster lap times since you really should match your gear ratios to each track, it's a good start. Keep in mind that if you're not reaching the top speed that you are expecting given the amount of HP you have, it could be that your car has a large frontal area resulting in excessive aerodynamic drag.

Note: Shifting so that the next gear catches the max torque RPM spot maximizes fuel economy.

Edited to correct for brain fade...
 
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Disavowed
Torque helps acceleration while HP determines your top speed. In theory, you'll get the best acceleration if you get your gears so that your next gear fall in the rpm range where torque curve meets the HP curve. Although this doesn't necessarily translate directly to faster lap times since you really should match your gear ratios to each track, it's a good start. Keep in mind that if you're not reaching the top speed that you are expecting given the amount of HP you have, it could be that your car has a large frontal area resulting in excessive aerodynamic drag.

Note: Shifting so that the next gear catches the max torque RPM spot maximizes fuel economy.
Click to expand...
So in a VW Golf V I should make my car drop to 2,000RPM with each gear change?
 
That golf max torque is rpms is around 2100 to 2400RPMs?, if so I can see it be good for tracks like very technical tracks. I usually run midrange turbo to get nice torque in the midrange. The high range turbo I found to be pretty much junk, as when most car shift they drop into a midrange powerband. The less HP and more torque the cars have they seem to work way better around technical tracks as RPMs are very low.
 
Master_gamer438
That golf max torque is rpms is around 2100 to 2400RPMs?, if so I can see it be good for tracks like very technical tracks. I usually run midrange turbo to get nice torque in the midrange. The high range turbo I found to be pretty much junk, as when most car shift they drop into a midrange powerband. The less HP and more torque the cars have they seem to work way better around technical tracks as RPMs are very low.
Click to expand...

The Golf still runs much faster up around 4-6K RPM, because that's where peak HP is, for the reason I explained above.

I always use high RPM turbos when possible, for two reasons.
1. More HP per PP
2. With good enough gears it's always faster.
 
CSLACR
The Golf still runs much faster up around 4-6K RPM, because that's where peak HP is, for the reason I explained above.

I always use high RPM turbos when possible, for two reasons.
1. More HP per PP
2. With good enough gears it's always faster.
Click to expand...

I don't have a Golf Mark V so I can't say for sure but if you're running faster from 4-6k then by all means setup your gear ratio for that. What I gave is a theory that works well as a general starting point for most cars. This will, of course, vary from car to car.
 

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