The definitive GT5 transmission tuning guide.

[grenadeshark]

GT5 Transmission tuning guide.


EDIT: Updated 7/13/2011. Tuning section added back in

This guide is going to cover everything you need to know to properly setup your transmission to get the most out of the Power curve of your vehicle. This guide is mostly directed at people who are looking for that extra 1.5 seconds in a 60 second straight line sprint. This will not make your cars blow away the competition.

This guide has multiple parts and will most likely need to be rewritten by someone in the community who cares more about layout and quality design then me. This is a summation of everything I have learned from reading other guides, in game testing and actual real life racing experience.

Layout:
Part 1. Engine Power Curve Theory
Part 2. Power Curve in relation to transmission
Part 3. Practical use of said information
Part 4. Tuning your transmission
Part 5. Excel calculator to make things a bit easier (not easy).

Part 1. Theory

Why is it important to tune your transmission to go hand in hand with the Power Curve of your car? The answer to this is simple and complex at the same time. On some cars it isn't. On others, it is. The first thing we need to understand is what is a cars power curve and what does it mean? Basically, a power curve is the combination of HP and TQ values over a given RPM range expressed graphically. An easier explanation of this is to look at your tuning menu on any given car. See the orange and green lines that are graphed in the bottom right corner of your screen? That's your engines power curve.

What makes up a good power curve? Well it all depends on your purpose for a car. Two differing examples of what exists in the real world are shown in Exhibit A.

On the left, you have a car that has a TQ curve that intersects the HP curve at about mid RPM range of the given engine.
On the right, you have a car that has a TQ curve that intersects the HP curve at a high RPM range.

Given that these two cars produce the same absolute HP and TQ numbers, we can see that the car on the left will have more low end TQ and the car on the right will have more high end TQ. This means that basically the car on the left will accelerate faster at low RPMs and the car on the right will accelerate better at high RPMs.

The second part of the power curve to look at is where it peaks at and what happens after the peak. Generally speaking, you want to look at the HP number after it crosses TQ (5252 rpm) on the graph. Take exhibit B.

We have 4 graphs with varying HP curves. If all these curves have the same basic HP peak, the one on the bottom left will be the fastest car (all other things being equal). The reason for this is because of a number of reasons.

First of which is that the horsepower stays at its maximum all the way to the rev limiter. This is good because physics tells us that a car cannot accelerate any faster than its peak power in a gear suitable for the speed it's going. In other words, you should never shift to the next gear if your car is currently at its HP peak. It is only once your car has dropped from its peak horsepower that it may be advantageous to shift gears. This is due to the effects of gearing on the power curve and will be talked about later.

Secondly, a car with a flat power curve will accelerate smoothly and be easy to tune. A car that has large spikes in its power curve is very "peaky" and will accelerate very hard for very short periods of time. This causes problems with traction , gearing and even suspension tuning. Long story short. If at all possible, you want your power curve to continue increases all the way up to rev limiter, or be flat and not dropping at the rev limiter. Granted, most production vehicles don't meet this criteria so you have to work with what you have.

Ex. 2 cars. One making 300 hp from 6000-9000 RPMS with a 9000 the rev limiter will more times than not be faster than a car making 310 HP from 7500-8000 RPMS with a 9000 rev limiter. More on this later as well.

Part 2. Power curve in relation to the transmission.

So you tuned your car to get the best possible power curve out of it. Great! Next step we need to do is figure out how you can use the transmission to get the most out of your power curve. There are a lot of factors in making this decision and I am going to cover a few.

1. Traction.
There is no amount of power that is beneficial beyond the maximum traction capacity of your tires (drifting and extreme example excluded). You can't accelerate faster than traction will allow. This is a very important concept and is the one of the first things you shoulder consider when tuning your transmission.

2. What speed range will you be covering?

A car that does 200 mph will not necessarily be fast on a track where the top speed is 120 mph. Gearing your transmission for the track in question is a very high priority. In other words, making sure your car uses every gear to a given top speed will generally result in a faster lap time. There are many exceptions to this rule. One being that shifting too often will slow you down more than it will speed you up. Another being that optimal gearing accounts for the power curve of your engine, not just the speed of the track. If you set your final gear ratio too high (bigger number), you can end up with the opposite effect of what you are trying to accomplish.

3. Power curve in relation to transmission gearing.

You have to account for the RPM range that the engine is most efficient in compared to the RPM range that any given set of gearing will change that RPM. If your engine falls flat after 8000 RPMs and you have a 10k rev limtier, having an extremely short gear set (higher final gear ratio) could cause you to operate mostly above 8000 RPMs. This will have a detrimental effect on acceleration compared to a gear set that would optimize the 6000-8000 RPM range of that same engine.

In summary, you have to account for both speed of the track and the power curve of your engine to figure out exactly how much to change your gearing for any given track. Remember, tall gearing (lower numbers) means a larger range of RPMs will be covered in each gear and short gearing (bigger numbers) means a small range of RPMs will be covered in each gear.

Part 3. Practical use of said information.

In real life, high amounts of TQ at low RPMs translates to real world performance. You can feel the TQ off the line as you speed away from a red light. In racing and in this game, this is not necessarily the case. Let's take any given launch on any given race in GT5. You mash on the accelerator and wait for the timer to say GO! Your car immediately starts to move forward and you either bog down a bit and drop RPMs or sit on the rev limiter and slowly increase speed as your car gains traction.

Either way, your car does not spend almost any time in a low RPM range off the line. The only time this would occur is if you bog down so heavily due to low power and too much traction. It's not all that common. What is more common though is you burn out your tires off the line.

Now, as we are moving through the gears we notice something. A very high percentage of all racing that occurs in this game occurs at the top end of the RPM range. If your car has a 8000 RPM rev limiter, you can be sure that most of your racing will be spent between 4500 and 8000 RPMs. Even as you go into a turn you downshift into the appropriate gear which raises your RPM back into the 4500+ range. There are very few situations in GT5 where having high amounts of power at low RPMs will be more beneficial then high amounts of power at high RPMs. Even on tracks with extremely slow curves, moving into 1st gear should put your car up enough in the RPM range that low end power will be basically useless.

So what does all this information mean to me? How can I apply this to making me faster in game?

In this game (and I say game, because it's not necessarily indicative of the real world), Power at high RPMs matters more than Power at low RPMs. A good example of this situation is a tuned down muscle car. Sure, it has 450ft/lbs of TQ at 2000 RPMs! This same car has a 7000 RPM rev limiter and makes closer to 200 ft/lbs of TQ at the rev limiter. That means its only making 266.57 HP @ 7000 RPMs. Now let's take our small engine car and compare it. Sure, it only makes 147ft/lbs of TQ @ 2000 RPMs. But, it makes 300 HP @ 7000 RPMs. That means it makes 225.09 ft/lbs of TQ @ 7000 RPMs. That means this same car will out accelerate that muscle car at the same RPM given the same gearing!

This happens in real life as well. The same reason you see Supra's, Civic's, Evo's and other small engine cars outrunning equivalent muscle cars at higher speeds is due to high end TQ production of the engine versus the low end TQ production of similar muscle cars. This is not always the case and there are examples from both ends of the spectrum. In this game, you are better off having a car that performs like a civic in real life then a 69 Camaro. This is especially evident once you start tuning the cars and find the big displacement vehicles power curves falling flat at high RPMs and the small displacement vehicles power curve getting flatter and bigger as the RPM rises. Again, this is not always the case, but in this game, power up top matters more than power down low.

Part 4. Tuning your transmission. EDIT: Updated 7/13/2011

A couple of things need to be said first to help get you through the process of tuning your transmission.

The power drop off of your car towards the redline will help you decide when to shift. Remember though, that the effects of gearing become less and less apparent when you are in higher gears. What we can take from this is that in many cars, even though there is a drop off in your power curve towards the redline, the effects of gearing in 1st-3rd will generally overcome said drop and it will be still worth shifting at or near the redline.

Another consideration needs to be our shift points and the RPM we want to be in the next gear when we do shift. If your car starts making power around 6200 rpms, there is no reason to be at 7000 rpms already when you have shifted into that gear. This is the single greatest mistake in my opinion, people who tune transmissions make. They detune their car too greatly and do not modify the transmission to make use of the available power.

Being that I have not posted a tuning calculator, many of my methods are going to require you to guestimate. The first two things you should guestimate is the RPM you want to be at in the next gear and your shift RPM.

Example. Car A makes 286 hp @ 7200 rpms with a 9500 redline. It has a flat powerband up to 8900 rpms. It has substantial drop off of power after 8900 rpms. This means that in reality, we will be working with 1700 rpms in our transmission tune. But, knowing the effects of gearing, we will have 2500 rpms to use in 1st gear, 2300 in 2nd, 2100 in 3rd. This is because of the effects of gearing on the lower gears overcomes in most cases the power drop off. Your car may vary. If your HP line drops straight down after the peak, only go to the redline in 1st year and drop back to the power drop off in the next gears.

So, basically our car is going to look like this:

1st-2nd shift will occur at 9500 redline
2nd-3rd shift will occur at 9300
3rd-4th shift will occur at 9100
4th-5th shift will occur at 8900


So, knowing these ratios we can tune the transmission. What we need to find out first is the top speed of our car. So, we setup the transmission to our theoretical top speed. You can test this quite well at daytona speedway in offline mode. The way I tune, i Like to have about 500-1000 rpms left after I hit my top speed in my top gear. Remember, that the in game MPH that is listed is only your maximum top end with no wind resistance. Your in game speed will be quite lower. Let's say that through all our testing, we decided that 196 mph gets us to our top speed (or as much as we can get on daytona speedway) and leaves us with 500-1000 rpms left for draft.

Great, you are past step 1. We now know our 5th gear ratio. As we progress we will always try to keep this ratio exactly the same. So if you are running a 4.0 final gear and a 1.0 5th gear, your multiplier is 4. If we change our final gear to 2.0 and our 5th gear to 2.0, we still have the same ratio of 4. This is important to keep track of as the gearing will likely change to completely new numbers, but the ratios will stay the same. The in game MPH calculator on the transmission is a good indicator of the ratio. If you keep that number the same via your 5th gear, you will have basically the same ratio. Long story short, if the car felt like it was its best when the setting was at 196 mph top speed, we will keep it that way regardless of the rest of our tuning.

So theoretical car A has a final gear ratio of 3.047 and a final gear of 1.132 with a listed top speed of 196mph. We will work backwards from here.

Gear high/ Gear low * shift point = new RPM in next gear

We know our shift point will be 8900 from 4th gear to 5th gear. So:

Where 1.132 is our 5th gear ratio
Where X is 4th gear
8900 is our shift point in 4th gear
7200 is where we want to be when we shift into 5th gear.

1.132/x * 8900 = 7200

So x = 1.399

In other words, we want our 4th gear ratio to be 1.399. We do the same equation for the rest of the gears.

1.399/x * 9100 =7200

x= 1.768

Thus far we have
5th gear ratio : 1.132
4th gear ratio: 1.399
3rd gear ratio: 1.769

1.769/x * 9300 = 7200

x = 2.285


2.285/x * 9500 = 7200

x = 3.015

So in total, we end up with:

5th gear ratio: 1.132
4th gear ratio: 1.399
3rd gear ratio: 1.769
2nd gear ratio: 2.285
1st gear ratio: 3.015

One thing to reference here is this method could create a very long first gear. This could make the starts of your races less than pleasant. Feel free to shorten up your first gear to help you get off the line. It will only effect the 1-2 shift and you generally don't make that shift many times on a race track.

Let's test our theory to make sure the math worked. Say we are shifting from 2nd to 3rd and want to end up at 7200 rpms in 3rd gear.

So. 1.769/2.285 * 9300 = x

x = 7200.

At this point, the first thing you are going to find out is that sometimes, the transmission calculator in game just doesn't allow the values you want to put in. No worries! There are solutions to that as well. This is a complicated process that can only be figured out with a bunch of practice. The good news is, I have never found a car I couldn't make the values fit into! As long as you are using realistic shift points and new gear rpms, you should be able to get it to work.

How you do this is by adjusting the Top speed ratio up and down a notch or two, then messing with the final gear ratio. After that, you mess with your 5th gear ratio to get it back to the 196 mph or whatever top speed you wanted. With practice, you will see that it is predictable and you will be able to know exactly which way to adjust the top speed number and your final gear number to make this work.

Another tip is that you can expand your shift RPM in lower gears if you need to. Example: You normally shift at 8500 and want to end up at 7200. Well if you cannot get the gearing to fit in the transmission tuning menu, try shifting at 8500, but ending up at 6800-7200. This is what real cars do. My method tries to extrapolate the absolute best out of a car. But, if you just cannot get a gear set to work, don't worry about ending up a bit lower then your expected new rpm in the next gear. Do whatever it takes to make it fit (within reason).

This is the method I use to create unbeatable acceleration cars. If you are having some problems, just post your questions and I will help as much as I can.


Part 5. Tuning Calculator. Coming Soon.

Update: Being I was never able to accurately model the in game transmission on my spreadsheets, I can only give out the equations and the methods I use to make tuning decisions.

 

[drivehard]

I got lost back at calculating the amount of torque for any given RPM.

"Ex. Car makes 260 hp @ 7000 rpms = 195 TQ @7000 rpms"

Where would I get these numbers?

 

[niky]

Definitive it isn't if you don't have an explanation of how this all relates to wheel torque, which is all that really matters in tuning gears.

 

[Adrenaline]

I got lost back at calculating the amount of torque for any given RPM.

"Ex. Car makes 260 hp @ 7000 rpms = 195 TQ @7000 rpms"

Where would I get these numbers?

If I follow correctly, which I very well may not, it's a calculation of the engines HP at the flywheel, manipulated by the ratio of the specific gear, in the transmission being used.

It's much easier, if you focus on what's actually happening, rather than how it's happening.

Take a look at the image below.


In A we see someone who shifts at redline 9000rpm(the second vertical line on the graph) when they shift, the engine RPMs drop to the first vertical line on the graph, 7000rpm. So during their typical acceleration and driving, the car will always be operating between 7000 and 9000 rpm.

Now look at graph B, for a person who shifts at 7500rpm, which results in the same 2000 rpm drop, but this time into the 5500rpm range. Their normal operation will be in the 5500-7500rpm range.

By comparing these 2, you can see that the 5500-7500 operating range, will benefit from max torque at their lowest rpm and then shift at the peak of their max HP. Whereas the person in graph A, will shift down to max power, and only lose HP from there on.

Some math is involved, because you want to find the range that provides the highest amount of HP/TQ over the entire course of the RPM range on average.

How to weigh the benefits of torque vs HP, their benefits on acceleration and speed though, is beyond me

 

[bmw_e36m3]

Is the 5252 based off something? Or is that just the number needed for thr equation. Basically want to know what it represents.

 

[Motor City Hami]

What is all of this effort worth calculated into lap time? Honestly, can anyone quantify that.

I see huge gains in lower horsepower vehicles and very, very, very little in the super cars.

 

[TT3AZ]

There are gt4 tuning guides, that you can download, I recomend you all to download.

 

[esoxhntr]

i posted this in the other thread as well

grenadeshark is right. you guys need to draw out the table. for many cars, shifting at redline just works out -- these are typically high revving cars with very narrow power bands that peak waaaay up in the rpm band (near redline). for others it does not. below is a table that propably will not align correctly for a muscle car that makes a lot of torque down low

off the top of my head, the car made 305hp@4800 & 390@3000 lb/ft (go SBC). peak numbers aren't really important. the torque curve is. if you can visualize the torque numbers below, you will "see" the motor has a very flat curve that peaks early. not uncommon for v8s.

gear ratios are:

Gear...Ratio....Shift Point......New RPM
1st.....2.5325..5250.............0
2nd....1.915....5000.............3969
3rd.....1.53.....5000.............3994
4th.....1.23.....5000.............4019
5th.....0.99........................4024 .

RPM....Engine Tq...1st...........2nd..........3rd..... ....4th..........5th
2000...373...........944.6225...714.295. ....570.69....458.79.....369.27
2250...375.5........950.95375..719.0825. ..574.515...461.865...371.745
2500...378...........957.285.....723.87. .....578.34.....464.94....374.22
2750...384...........972.48......735.36. ......587.52.....472.32....380.16
3000...390...........987.675.....746.85. .....596.7.......479.7.....386.1
3250...388...........982.61......743.02. ......593.64.....477.24....384.12
3500...386...........977.545.....739.19. .....590.58.....474.78....382.14
3750...379...........959.8175...725.785. ....579.87.....466.17....375.21
4000...372...........942.09......712.38.......569.16.....457.56....368.28
4250...359...........909.1675...687.485. ....549.27.....441.57....355.41
4500...346...........876.245.....662.59. .....529.38.....425.58....342.54
4750...326...........825.595.....624.29. .....498.78.....400.98....322.74
5000...306...........774.945.....585.99......468.18......376.38...302.94
5250...284...........719.23......543.86.......434.52......349.32... 281.16
5500...262...........663.515....501.73.. .....400.86......322.26 ...259.38
5750...237...........600.2025...453.855. ....362.61......291.51...234.63
6000...212...........536.89......405.98. ......324.36......260.76...209.88

The numbers in the gear column are engine torque * gear ratio (ie. torque at tranny). you guys will say torque at wheels is what we're concerned with and that would equal engine tq * gear ratio * final drive - drivetrain losses. while true, i subscribe to KISS (keep it simple stupid) - final drive is a constant so we can omit it and drive train losses we're going to have to live without.

The formula to get where you will be in the next gear rpm wise after changing is rpm*(gear2ratio/gear1ratio)

I believe this cars redline is at 5750rpm. using the chart we can see the best acceleration is achieved by shifting at 5250 in 1st and about 5000k afterwards. if i had more rpm vs torque points plotted you could get real precise. the idea is to shift gears when the torque @ tranny in the next gear is equal to torque at tranny in current gear. if you shift too late, say 5750 in 1st and end up at 4500 in 2nd, you are not utilizing the engine & tranny to its optimum

 

[Rotary Junkie]

I have a problem with your first graphs (I've not read the entire document yet mind you)...

Power and torque always intersect at the same RPM. 5252 if you're using HP and ft-lbs, not sure about other measurements. So technically the one that has them intersect at a "higher RPM" is a lower revving motor by far.

Edit: Skimmed it... No mention of methods to run closer ratios while keeping top speed high (which is also a good way to get 1st long enough to not create excessive wheelspin), nor methods to get ridiculously wide gear ratios (which do have practical uses with certain vehicles or those that have been heavily choked via power limiter).

 

[Xr3CaRstI]

There are so many factors that need be included. It's hard to give a definitive method applicable to every car.

Variable valve timing is important here. Especially V-Tec. They run really high RPMs and their torque curve gets changed when it hits the v-Tec crossover point. Before crossover it's using smaller cam profiles and bigger ones after. When Tuning the gears of this type of engine we need to consider the crossover point and keep the revs inside the large profiles powerband. Shifting too far from red line with bad gearing will have you falling under the v-Tec crossover point, that's no good.

Many newer cars are using some form of variable valve timing these days, something to consider.

 

[grenadeshark]

I am going to try to work on some of the concerns that I have been seeing and update the guide accordingly!

I got lost back at calculating the amount of torque for any given RPM.

"Ex. Car makes 260 hp @ 7000 rpms = 195 TQ @7000 rpms"

Where would I get these numbers?

To start off. Go to your tuning page and check the numbers for your given car. It will give you a HP at a given RPM and a TQ rating at a given RPM. Using these two values, you can calculate the other at the same RPM and guestimate the values of the graph in game. It's not a perfect science in game (it is in real life).

Definitive it isn't if you don't have an explanation of how this all relates to wheel torque, which is all that really matters in tuning gears.

I explain power to the wheels in numerous places all over this guide. Not trying to say you didn't read it, but can you explain a little bit more what you believe is not being demonstrated here?

How to weigh the benefits of torque vs HP, their benefits on acceleration and speed though, is beyond me

All engines have their HP and TQ curves intersect at 5252. The reason for this is in the method of calculating the values. HP = TQ * RPM / 5252 will always result in a graph that looks similar. I really need to spend some more time drawing the graphs, but basically it was showing a car with a higher RPM range (left) and a car with lower RPM range (right) The car on the right redlines at say 7000 RPMs while the car on the left redlines at say 9000. The absolute values were not important to what I was trying to get across. But, the graph doesn't do a good job of illustrating that I suppose. I'll work on remaking the graphs.

Taking the second part of your question. There is no such thing as one more important then the other. They are functions of each other. What is important though is figuring out how one or the other relates to wheel power. You can figure this out by using the calculations I posted. Remember, at any given RPM if you know the HP or the TQ, you can figure out TQ being theoretically sent to the wheels (ignoring drive train losses).

Also adrenaline, the graph you drew is a good representation of what I was trying to show, but ultimately incorrect. TQ always intersects HP at 5252 RPM. Therefore the car on the left has a higher RPM range then the car on the right.

Edit: Skimmed it... No mention of methods to run closer ratios while keeping top speed high (which is also a good way to get 1st long enough to not create excessive wheelspin), nor methods to get ridiculously wide gear ratios (which do have practical uses with certain vehicles or those that have been heavily choked via power limiter).

If you read close enough, you will see there is a mention:

"1. Set the top speed slider 20-25mph higher than your expected top speed. If you don't know your top speed, hit a oval and find it out. If it's 155, set it to 180. Higher power cars need to set this number even higher than expected top speed (30-40 mph). This is mostly to allow for draft and give us a base set of gears that are usable. This is a general rule.

The alternate method is to set the top speed slider to maximize your Power curve in any individual gear. This is very time intensive and I will not be covering this style of tuning in this guide. Basically you want to maximize your acceleration by making sure you are always in the optimal power range of your car. "

I covered a general way in tuning most any car to be effective. Wide ratios and short ratios work for one reason, the power curve of the engine. If you have a car that makes max HP at 5000 RPMs and carries it all the way to a 10,000 redline, a wider ratio makes sense. If you have a car that makes max HP near redline and only near redline, it makes sense to carry a shorter ratio. The second part of my statement is basically what I used to cover the extremities of tuning. I say extremities, because those methods still don't necessarily produce noticeably better acceleration.

There are so many factors that need be included. It's hard to give a definitive method applicable to every car.

Variable valve timing is important here. Especially V-Tec. They run really high RPMs and their torque curve gets changed when it hits the v-Tec crossover point. Before crossover it's using smaller cam profiles and bigger ones after. When Tuning the gears of this type of engine we need to consider the crossover point and keep the revs inside the large profiles powerband. Shifting too far from red line with bad gearing will have you falling under the v-Tec crossover point, that's no good.

Many newer cars are using some form of variable valve timing these days, something to consider.

Variable Valve timing is depicted in the power curve. Understand that power to the wheels is what really matters and VVT is just a part of an equation really. What will matter is the power available, the RPM range, and TQ sent to the wheels.

EDIT. I belive I need to cover final gear ratios a bit more as people has a basic misunderstanding of what they do. In short, they remove or add load to an engine which allows it to rev more freely/slowly. That's about it. I understand this is a very simple summary of what gears do, but you can use the concept to expand out to actual tuning (which is basically what my guide covered).

Another addition to the guide later on will need to be how to pick the right parts to get your power curve looking the way you want it to look. Also, an expanded coverage on how to tell what a good power curve looks like.

 

[articzap]

So much fail on this. I'll write up when I get home. From the first few paragraphs I read, there was to many untrue statements being made, period.

As said, I'll expand on this when I get home from work.

 

[grenadeshark]

So much fail on this. I'll write up when I get home. From the first few paragraphs I read, there was to many untrue statements being made, period.

As said, I'll expand on this when I get home from work.

Please do. I have a feeling your definition of fail might just be some wording discrepancies

 

[Xr3CaRstI]

Basically your method fails to factor in minimum rpm not to fall under to insure your staying above a v-Tec crossover in comers. Or maybe I missed it with it's Radio Instructions style of explanation. Either way, I'm just fine with my gear tuning, thanks.

 

[grenadeshark]

Basically your method fails to factor in minimum rpm not to fall under to insure your staying above a v-Tec crossover in comers. Or maybe I missed it with it's Radio Instructions style of explanation. Either way, I'm just fine with my gear tuning, thanks.

A bit hostile? No? Your "vtec" crossover is nothing more then a set of power values at a given RPM. If you gear your car to stay within the most optimal RPM range, you will be in your "vtec" range.

But, to go out of my way to explain a part of the power curve which inherently has no relevance to in game tuning is beyond me. Vtec in this game is expressed just like any other car. There is no difference. There is just HP/TQ ratings at a given RPM. That's it.

 

[drivehard]

I see. I will continue on down the page and test this out later on tonight.

I appreciate you posting this. I may have some more questions about how to use your guide. Any help is appreciated. Thank you.

 

[grenadeshark]

Ok Guys, what do you think about this explanation that would replace Exhibit A. This is a simple explanation and will be expanded if you guys think it works better.

Ok, there is one big problem with using the in game graphs. They are utterly and completely dead wrong when it comes to drawing out the TQ curve. By definition, the TQ curve has to cross at 5252 RPM and it does not in these pictures. But, the graphs can be helpful nonetheless if we ignore the TQ curve and focus on the HP curve.

Lets take the picture on the left. This particular car makes 194 TQ @ 7000 RPMs. I can tell this by checking the in game statistics.

The picture on the right has a HP curve that peaks at the redline of 7000 RPMs. We can calculate the TQ being made. 239 HP * 5252 / 7000 = 179 TQ.

What this means is that the car on the left is actually producing more TQ at 7000 RPMs then the car on the right. This is counter to what you would believe by looking at the graphs directly. Basically, around 6000+ RPMs, the car on the left starts to out accelerate the car on the right. Being he has a higher rev limiter as well, he will get to use the multiplying effect of 1st gear for longer then the car on the right (ignoring final drive ratio). Since most of the racing in this game is done at higher RPM ranges, the car on the left will most likely be faster when it counts. I will explain later in the guide why having high TQ at High RPMs is more valuable then High TQ at low RPMs in this game.

 

[Xr3CaRstI]

It's important to tune the gears close enough to insure you don't fall under vtec. I'm not saying it again, personally I hate Honda, so it's not high on my give-o-crap meter.

But here is where it applies to the game, Amuse S2000 and 9000rpm(or close, I'm not in front of the game) red line.

When approaching a 2nd gear corner, you need insure the lowest speed you will be in that corner is at a gear speed/rpm above the crossover.

When tuning gear and figuring out shift points you need to observe (not mathematically calculate) the speed and exact rpm your tac falls to when you grab next gear.

I don't see you making these important observations (especially tuning vtec motors) that is so crucial to observe.

Gear tuning is done on the track, not entirely on the calculator.

Next.

 

[grenadeshark]

It's important to tune the gears close enough to insure you don't fall under vtec. I'm not saying it again, personally I hate Honda, so it's not high on my give-o-crap meter.

But here is where it applies to the game, Amuse S2000 and 9000rpm(or close, I'm not in front of the game) red line.

When approaching a 2nd gear corner, you need insure the lowest speed you will be in that corner is at a gear speed/rpm above the crossover.

When tuning gear and figuring out shift points you need to observe (not mathematically calculate) the speed and exact rpm your tac falls to when you grab next gear.

I don't see you making these important observations (especially tuning vtec motors) that is so crucial to observe.

Gear tuning is done on the track, not entirely on the calculator.

Next.

You keep naming this mythical crossover point. It doesn't exist in game. HP/TQ at any given RPM range is all that matters. If your car has a major power drop below X RPM, you need to make sure your tuning your gears to avoid this drop. I go over this extensively...

Your second point makes me believe that you did not read the tuning portion of the guide.

I talk about RPM drop between gears, optimal shift points, tuning for the track... All of this is mentioned. Do I really need to pull out every single line that contradicts exactly what you just said?

Tune however you feel is best. Criticize me where you think I am making mistakes. But, don't just flat out ignore everything I write and then claim I didn't write it.

 

[Xr3CaRstI]

You know what, your right, I didn't go over it as extensively as I should of, if you covered it, my bad. It didn't appear clearly when I went over it, I'll take the time after work to do so.

But there is nothing mythical about a choked up Honda lol. While the transition is not as sharp, it's in the game how brutally weak those things are down low.

 

[grenadeshark]

You know what, your right, I didn't go over it as extensively as I should of, if you covered it, my bad. It didn't appear clearly when I went over it, I'll take the time after work to do so.

My paragraphing and formatting leaves a lot to be desired. This is still very much a work in progress and I need to really figure out if people are able to use this information or not.

All the explanation in the world is basically useless if no one understands it the way I explain it. I am hoping people will give me their inputs on things they don't understand, disagree with or think I could put better. The first graph being a prime example of where a lot of people are getting confused.

I am not doing this to boost my own ego. I just feel like their is an inadequate supply of valuable information covering this subject accurately. Most anyone can play around long enough and find a gearing setup that makes them faster.

I am trying to create a system to where anyone can understand why the changes they made are helping them out in hopes that they can further tune their cars.

Also, once someone understands this information, they will figure out why some cars in a similar PP range with lower HP/TQ numbers still blow them away.

I raced a guy last night that had the exact same car as me with 3 HP less in his tune on ss7. I literally put 30+ car lengths on him by 150 mph and out ran him in top speed. This is all because of the parts I chose for the car compared to what he chose and the gearing setup I had versus his.

 

[articzap]

On the left, you have a car that has a TQ curve that intersects the HP curve at about mid RPM range of the given engine.
On the right, you have a car that has a TQ curve that intersects the HP curve at a high RPM range.

Given that these two cars produce the same absolute HP and TQ numbers, we can see that the car on the left will have more low end TQ and the car on the right will have more high end TQ. This means that basically the car on the left will accelerate faster at low RPMs and the car on the right will accelerate better at high RPMs.

Horsepower is a direct calculation from torque. They will always cross at 5252 RPM. The only time they may appear to cross at different RPM is when the scale for horsepower and torque are different. This is commonly found in the game. You must look past that though.

First of which is that the horsepower stays at its maximum all the way to the rev limiter. This is good because physics tells us that a car cannot accelerate any faster than its peak power in a gear suitable for the speed it's going. In other words, you should never shift to the next gear if your car is currently at its HP peak. It is only once your car has dropped from its peak horsepower that it may be advantageous to shift gears. This is due to the effects of gearing on the power curve and will be talked about later.

You should shift 200 RPM past peak HP.

Secondly, a car with a flat power curve will accelerate smoothly and be easy to tune. A car that has large spikes in its power curve is very "peaky" and will accelerate very hard for very short periods of time. This causes problems with traction , gearing and even suspension tuning. Long story short. If at all possible, you want your power curve to continue increases all the way up to rev limiter, or be flat and not dropping at the rev limiter. Granted, most production vehicles don't meet this criteria so you have to work with what you have.

Where the power drops off has no effect on acceleration, unless you shift way to late. We are tuning to keep the gear in the power band, so where the power band is located has no effect on final acceleration, the gearing does.

Ex. 2 cars. One making 300 hp from 6000-9000 RPMS with a 9000 the rev limiter will more times than not be faster than a car making 310 HP from 7500-8000 RPMS with a 9000 rev limiter. More on this later as well.

Absolutely wrong. The car with more horsepower will be faster, with a proper gear tune of course, and this is why we are here.

1. Traction.
There is no amount of power that is beneficial beyond the maximum traction capacity of your tires (drifting and extreme example excluded). You can't accelerate faster than traction will allow. This is a very important concept and is the one of the first things you shoulder consider when tuning your transmission.

True to an extent. The most redicilous part of that statement is saying that you need power to drift. A lot of drift cars can actually grip quite nicely, granted maybe a minor tweak, but the point about the drifting comment is that you can have a car that doesn't break traction in a straight line and still drifts extremely well. Drifting is more based on grip then a loss of.

2. What speed range will you be covering?

A car that does 200 mph will not necessarily be fast on a track where the top speed is 120 mph. Gearing your transmission for the track in question is a very high priority. In other words, making sure your car uses every gear to a given top speed will generally result in a faster lap time. There are many exceptions to this rule. One being that shifting too often will slow you down more than it will speed you up. Another being that optimal gearing accounts for the power curve of your engine, not just the speed of the track. If you set your final gear ratio too high (bigger number), you can end up with the opposite effect of what you are trying to accomplish.

3. Power curve in relation to transmission gearing.

You have to account for the RPM range that the engine is most efficient in compared to the RPM range that any given set of gearing will change that RPM. If your engine falls flat after 8000 RPMs and you have a 10k rev limtier, having an extremely short gear set (higher final gear ratio) could cause you to operate mostly above 8000 RPMs. This will have a detrimental effect on acceleration compared to a gear set that would optimize the 6000-8000 RPM range of that same engine.

In summary, you have to account for both speed of the track and the power curve of your engine to figure out exactly how much to change your gearing for any given track. Remember, tall gearing (lower numbers) means a larger range of RPMs will be covered in each gear and short gearing (bigger numbers) means a small range of RPMs will be covered in each gear.

There is only one real optimal gear set for the car. Almost all cars in this game like short gears, especially for acceleration. A couple cars favor longer gears, extremely broad power bands and high horsepower/low traction cars come to mind. Your final drive should be the only thing adjusted for the track, not each gear.

Part 3. Practical use of said information.

In real life, high amounts of TQ at low RPMs translates to real world performance. You can feel the TQ off the line as you speed away from a red light. In racing and in this game, this is not necessarily the case. Let's take any given launch on any given race in GT5. You mash on the accelerator and wait for the timer to say GO! Your car immediately starts to move forward and you either bog down a bit and drop RPMs or sit on the rev limiter and slowly increase speed as your car gains traction.

Either way, your car does not spend almost any time in a low RPM range off the line. The only time this would occur is if you bog down so heavily due to low power and too much traction. It's not all that common. What is more common though is you burn out your tires off the line.

Now, as we are moving through the gears we notice something. A very high percentage of all racing that occurs in this game occurs at the top end of the RPM range. If your car has a 8000 RPM rev limiter, you can be sure that most of your racing will be spent between 4500 and 8000 RPMs. Even as you go into a turn you downshift into the appropriate gear which raises your RPM back into the 4500+ range. There are very few situations in GT5 where having high amounts of power at low RPMs will be more beneficial then high amounts of power at high RPMs. Even on tracks with extremely slow curves, moving into 1st gear should put your car up enough in the RPM range that low end power will be basically useless.So what does all this information mean to me? How can I apply this to making me faster in game?

In this game (and I say game, because it's not necessarily indicative of the real world), Power at high RPMs matters more than Power at low RPMs. A good example of this situation is a tuned down muscle car. Sure, it has 450ft/lbs of TQ at 2000 RPMs! This same car has a 7000 RPM rev limiter and makes closer to 200 ft/lbs of TQ at the rev limiter. That means its only making 266.57 HP @ 7000 RPMs. Now let's take our small engine car and compare it. Sure, it only makes 147ft/lbs of TQ @ 2000 RPMs. But, it makes 300 HP @ 7000 RPMs. That means it makes 225.09 ft/lbs of TQ @ 7000 RPMs. That means this same car will out accelerate that muscle car at the same RPM given the same gearing!

This happens in real life as well. The same reason you see Supra's, Civic's, Evo's and other small engine cars outrunning equivalent muscle cars at higher speeds is due to high end TQ production of the engine versus the low end TQ production of similar muscle cars. This is not always the case and there are examples from both ends of the spectrum. In this game, you are better off having a car that performs like a civic in real life then a 69 Camaro. This is especially evident once you start tuning the cars and find the big displacement vehicles power curves falling flat at high RPMs and the small displacement vehicles power curve getting flatter and bigger as the RPM rises. Again, this is not always the case, but in this game, power up top matters more than power down low.

And stop. More torque at lower RPM's means the power band can start earlier in the RPM range. In order to fully grasp the concept of accerleration, you need to throw torque out the window. Torque is what moves the car, but it doesn't describe the power band. Horsepower tells how useful that torque is at that RPM. Think of horsepower as an efficiency meter. Just because torque is decreasing per a given RPM, doesn't mean its not actually doing more, hence why horsepower can increase well torque decreases.

A lot of cars can be quite equal in this game. It's more important to keep weight down then to keep horsepower up. Not all big displacement engines fall off at higher RPM's. I'm quite sure you are making stuff up now. Power up top in all racing matters more then down low. You have to give yourself a wide enough power band, whether in real life or the game, to make use of the gear set you have.

2. Set your final gear ratio for the track you are racing on. Taller ratios (low numbers) promotes higher top end up until a maximum at which you can no longer accelerate faster due to wind resistance(among others). Short ratios (higher numbers) promote higher acceleration and lower top end. Take into account your power curve when making these consideration. A car that has a RPM range of 0-10000 but doesn't make power over 8000 will not do well with excessively short gearing.

Short gearing would benefit that car more. Please stop giving false information. You just need to shift at the appropriate times. I mean if you're making a transmission tune to stay within your power band, then redline has absolutely no effect on short or long gearing.

Another point to take notice of is that if your car has a flat HP curve from a low RPM, taller gearing will generally promote better acceleration. The reason being is the TQ transmitted to the wheels in a lower gear at a lower RPM will be higher then the TQ transmitted to the wheels at a higher RPM in the same gear. And since you cannot accelerate faster then your HP peak, gearing your car to use the entire RPM range of your flat HP line is extremely beneficial. Wasting RPMs by over shortening a car with a long flat HP curve will be detrimental to acceleration. Math proves this as well later on.

Granted a car like this will be fine with slightly longer gearing, does not mean it won't accelerate as hard at high RPM's. If the torque curve is flat as you describe, that means that the horsepower is going up at a 45 degree angle in relation to torque. And as I describe earlier, horsepower is nothing more then a meter to gauge how efficient the car is at putting that torque down at that RPM. In other words, rev away!

3. Tune first gear using the tires you will be racing with. Do a redline launch and move your first gear slider left/right until you get a small bit of a wheel spin, but mostly forward progress. If you cannot get traction by moving the slider all the way left, then you need to start moving your final gear ratio to the left. If the engine bogs down back to 50% RPMs, you went too far. Move the final gear ratio back to the right. Avoid extremes when tuning your 1st gear as too much alteration of the final gear ratio will result in a faster 1st gear, but the rest of your gears will be slower.

Ideally you want first gear as long as possible without bogging. I'm not sure how you can change first gear, until you have dialed in your final drive first. For that you need to start work on the last gear in the gear set first.

4 .Figure out the optimal shift RPMs for the engine. Ignore the transmission in making these decisions. Look at the HP/TQ curve and figure out when you need to shift (it's a bit of guess work). You can also do this on track very easily by getting on a ring and testing acceleration pulls in each gear.

Look at the pull level in each gear and figure out whether going to the rev limiter produces more or less acceleration in any given gear. An easy test is to get your car up to red line in any given gear under full acceleration. If when you shift at the rev limiter, your car pulls harder than it was in the previous gear, you need to shift earlier. If it continues pulling at the same rate or a bit slower, then continue shifting at the rev limiter. This requires testing and is not an exact science. You can look at your power curve to get an idea of where this will be on your car. If it drops significantly at any point, you can expect to shift very close to that point in general.

Almost all cars pull there hardest in the power band, this game included. The graph doesn't lie.

Alternate Method:Note: It is very hard to do this on a car that doesn't have a very flat HP curve. The game doesn't give enough exact numbers for the HP/TQ curves.

It supplies you with all the numbers you need. More information could be a lot more useful, but there is plenty enough there.

You can also do this mathematically which is what I do. Open an excel spreadsheet and document your TQ numbers at any given RPM that you care about. When I say "you care about", I mean on any given track, what is the most likely range you will be sitting in the longest. Is it a slow track with lots of low RPM pulls or a fast track with mostly high end RPM usage? (Hint: 95% of tracks are high end due to the ability to shift down and get your RPMs back up ). Note your transmission gearing in one row and the engine RPMs in another column. Now figure out your TQ at a given RPM. hp= (tq*rpm)/5252. Then multiply by the gear ratio (not final gear).

Ex. Car makes 260 hp @ 7000 rpms = 195 TQ @7000 rpms
195 * 3.25 (1st gear ratio) = 633.75 TQ

Note that information for each RPM level you plan on covering. I generally go in increments of 100, but increments of 500 will get you accurate enough results. As long as your HP curve is relatively flat, you should be able to figure out the HP by guestimating at each RPM level the HP output. If you cannot do this, then this method will not work. A trick to figuring out the drops of the graph is calculating the HP at your TQ peak. If your torque peak is at 3500 RPMs and your HP peak is at 7000, you can figure out your HP at 3500 RPMs as well. HP = TQ * RPM / 5252. Using this information, you can guestimate the values on the graph.

Once you have the information laid out, you want to make sure you are shifting at the point where TQ is still higher then it will be when you shift to the next gear. You calculate your TQ by the equation HP = (TQ * RPM)/5252.

Ex. Rev limiter is 9000 RPMs. When you shift, it drops back to 7000 RPMs.
7000 RPMs 3rd gear = 300 TQ
8000 RPMs 3rd gear = 285 TQ
9000 RPMs 3rd gear = 265 TQ
---------------------------------------------
7000 RPMs 4th gear = 275 TQ
8000 RPMs 4th gear = 265 TQ
9000 RPMs 4th gear = 245 TQ

In this example, you need to shift slightly before the rev limiter to maximize torque output to the rear wheels. In many other cases, shifting at rev limiter will be optimal. There is one major caveat here though. You can't just calculate TQ, you have to calculate power sent to the wheels. This requires multiplying the TQ at any RPM by the transmission gear ratio (IE: 1st gear 3.247, 2nd 2.56, etc). Let's take that same example and calculate the TQ sent to the wheels given 3th and 4th gears.

4th gear. 1.305 transmission ratio

7000 RPMs 3rd gear = 300 TQ *1.305 = 391.5
8000 RPMs 3rd gear = 285 TQ *1.305 = 371.9
9000 RPMs 3rd gear = 265 TQ *1.305 = 345.83
--------------------------------------------------------------

5th gear. 1.093 transmission ratio

7000 RPMs 4th gear = 275 * 1.093 = 300.58

Knowing that our car drops 2000 RPMs between the 3rd and 4th gear switch, we can see that if we shift at the rev limiter (9000 RPMs) we maximize the TQ sent to the wheels. We know this because the TQ sent to the wheels at 9000 RPMs in 3rd gear is higher than the TQ sent to the wheels at 7000 RPMs in 4th gear. Had the number in 5th gear been 346 or higher, we would know that we need to shift a bit earlier as our car is dropping power as the RPMs increase late in the RPM range. This is a hard concept to understand. The easy way to understand is to map it out yourself.

There is no need to open a spreadsheet for this reason, although there is other reasons to open one up that you haven't covered. Torque decreases with higher numerical gears and increases with higher numerical gears. Don't believe me? Go place a car on a dyno. Dyno the car in each gear. Watch in amazement.

TQ=Force * distance

Engine torque will always stay the same. So input a higher numerical value and suddenly you lost force. So why does a car feel faster in lower gears? Gear reduction.Gear reduction allows less torque to be used to achieve a much greater result.

Again, example. You are riding a bike up a hill. It has two gears 3:1 and 1:1. 1:1 is harder to pedal but you have to pedal a lot harder. Since there is more resistance, it allows you to apply more force which equals more torque. 3:1 offers gear reduction, aka less resistance.

I know that concept will shock most of you and most will say its against the laws of physics. Go try and measure some data. I've seen in the results.

5. Fine tune individual gear ratios. Now that we know the optimal RPM to shift at, we can slightly alter our gears to get the most out of the individual track we are racing. Do you find yourself at the top or bottom of a gear going into or coming out of a corner? Once you figure out the gear you want to change a bit, go back into your tuning menu. If you want the gear to be taller (last longer) then move the slider to the left. If you want to get to the next gear faster, move the slider to the right. You can also tune your top speed now using your final gear. Using the TQ calculations we made earlier, figure out the optimal RPM you want to be near your max speed and tune the slider accordingly. Remember, if you move the slider, you change the TQ output to the wheels and need to recalculate based on the new settings.

Just so its stated on record, you can not change one gear without effecting every other gear. If you make a change to one, you will be forced to change all of the others to keep your RPM drop as it was before.

----------------------------------------

So how should one go about calculating gear ratios?

First you need to know a few things.

First, how to use the top speed adjuster. The top speed adjuster need to be used in conjunction with the final drive.

Moving final drive low, numerically, then setting top speed to high, you end up with a starting gear set that will have a really low First gear and a wider 2nd - 6th. I do not recommend this setup.

Moving final drive high, numerically, then setting top speed to high, gives you the net result of all the gears being almost equally spaced. It's easier to tune with set setup.

No matter which way you do it, you will end up with a gear progression between first and 6th that is 75%.

Next you need to realize that N/A and in this game, supercharged cars respond well to lower gear progressions, under 20%. Turbo cars love longer gear progressions, higher then 20%. Take this with a grain of salt though. We're talking 18% vs maybe 22%. That small of a reduction isn't much. I would stray towards shorter gears then long, even in a turbo car.

Your power band is defined from the peak torque RPM to the peak horsepower RPM. When you shift, you should shift 200 RPM after the peak horsepower. Don't just go by the RPM's it gives you, look at the graph. If its flat but giving you the peak value just at the end of a rather flat curve, you can use a different RPM. Common sense.

Longer first and second will translate to shorter 3rd - 6th. Shorter will be faster 90% of the time.

Let's do a quick tune then.....


Set final drive to high numerically and then slide the top speed over. Certain cars will only go so fast, so keep it mind when sliding the top speed over.

Next, take 6th gear and make it has short as possible, high numerically.

Now go test on the track for top speed you need to hit. You should hit your top speed at the end of the power band, NOT THE LIMITER. If it's not where it needs to be adjust the final gear to make the changes you need.

So now your 6th gear and final gear are set. Now lengthen first until the car just starts to bog or it maxed, low numerically. You don't want to bog, but you do not want to bounce the limiter. It should be a clean burn, without hitting the limiter all the way to top speed of first gear. If you maxed out the gear, low numerically, move on and work with second gear to achieve this controlled burn.

Adjust the rest of the gears so the have an equal RPM drop. Having a longer second gear, low numerically is better then leaving it shorter, high numerically.

This will give you the best gearing for a power band period.

So what if the RPM drop is 1000 but my power band is 3000 RPM long? That's good. You can now go through corners and not have to waste a gear shift because you can be within the power band still. It's highly recommended you never shift to first while going around a track. It's just to short for any practical use.

 

[Nicktune]

Good read!!
Quote (So much fail on this)...There's always people saying cr4p about others people work...this happened to me with my suspension setup too

It Works!Your car pull like crazy

Good work:tup:

 

[grenadeshark]

Horsepower is a direct calculation from torque. They will always cross at 5252 RPM. The only time they may appear to cross at different RPM is when the scale for horsepower and torque are different. This is commonly found in the game. You must look past that though.


You should shift 200 RPM past peak HP.

I shouldn't respond to your anything you say after a statement like that. But, I am going to for the sake of anyone else taking your word as the truth.

When you shift is dependent upon the gear you are in and the power being sent to the wheels given all the present multiplier. I will give some examples after I go through the rest of your post.

Where the power drops off has no effect on acceleration, unless you shift way to late. We are tuning to keep the gear in the power band, so where the power band is located has no effect on final acceleration, the gearing does.

Where the power drops off have an absolute reference to when you should shift. The amount of TQ being sent to the wheels determines when you should shift, not a random 200 rpm past hp peak statement. Guess what, gearing effects this number.

Absolutely wrong. The car with more horsepower will be faster, with a proper gear tune of course, and this is why we are here.

Sure in a fake world where a car utilizes only 500 RPMs of its power band and your gearing is setup to only use that 500 RPM. Basically you would have a car with a top speed of 100 mph that got there extremely quickly. That is not applicable to racing or in game situations.

True to an extent. The most redicilous part of that statement is saying that you need power to drift. A lot of drift cars can actually grip quite nicely, granted maybe a minor tweak, but the point about the drifting comment is that you can have a car that doesn't break traction in a straight line and still drifts extremely well. Drifting is more based on grip then a loss of.

Really, that's what your attacking me on? Because I said maybe in this case of drifting?

There is only one real optimal gear set for the car. Almost all cars in this game like short gears, especially for acceleration. A couple cars favor longer gears, extremely broad power bands and high horsepower/low traction cars come to mind. Your final drive should be the only thing adjusted for the track, not each gear.

LOL. There are multiple ways to end up at the same results. Its the effects of multiplying. It doesn't care how you do it, just the end result. By the way, you absolutely tune individual gears for each track. If you only adjust final gear ratio, you might get 1 turn perfect, but might screw up 7 others.

And stop. More torque at lower RPM's means the power band can start earlier in the RPM range. In order to fully grasp the concept of accerleration, you need to throw torque out the window. Torque is what moves the car, but it doesn't describe the power band. Horsepower tells how useful that torque is at that RPM. Think of horsepower as an efficiency meter. Just because torque is decreasing per a given RPM, doesn't mean its not actually doing more, hence why horsepower can increase well torque decreases.

A lot of cars can be quite equal in this game. It's more important to keep weight down then to keep horsepower up. Not all big displacement engines fall off at higher RPM's. I'm quite sure you are making stuff up now. Power up top in all racing matters more then down low. You have to give yourself a wide enough power band, whether in real life or the game, to make use of the gear set you have.

I don't even think are you arguing with me on this point...

Short gearing would benefit that car more. Please stop giving false information. You just need to shift at the appropriate times. I mean if you're making a transmission tune to stay within your power band, then redline has absolutely no effect on short or long gearing.

Ill have to go back and see what your referencing here.

Granted a car like this will be fine with slightly longer gearing, does not mean it won't accelerate as hard at high RPM's. If the torque curve is flat as you describe, that means that the horsepower is going up at a 45 degree angle in relation to torque. And as I describe earlier, horsepower is nothing more then a meter to gauge how efficient the car is at putting that torque down at that RPM. In other words, rev away!

This all lies in the multipliers. Sometimes you can lengthen a gear ratio without dropping TQ sent to the wheels. This is 100% dependent on the power curve of the engine though.

Ideally you want first gear as long as possible without bogging. I'm not sure how you can change first gear, until you have dialed in your final drive first. For that you need to start work on the last gear in the gear set first.

Again, are we arguing? I dial them in simultaneously. This is more of an argument of tuning order then of tuning theory.

Almost all cars pull there hardest in the power band, this game included. The graph doesn't lie.

Did I disagree with that?

It supplies you with all the numbers you need. More information could be a lot more useful, but there is plenty enough there.

Again, I agree.

There is no need to open a spreadsheet for this reason, although there is other reasons to open one up that you haven't covered. Torque decreases with higher numerical gears and increases with higher numerical gears. Don't believe me? Go place a car on a dyno. Dyno the car in each gear. Watch in amazement.

TQ=Force * distance

Engine torque will always stay the same. So input a higher numerical value and suddenly you lost force. So why does a car feel faster in lower gears? Gear reduction.Gear reduction allows less torque to be used to achieve a much greater result.

Again, example. You are riding a bike up a hill. It has two gears 3:1 and 1:1. 1:1 is harder to pedal but you have to pedal a lot harder. Since there is more resistance, it allows you to apply more force which equals more torque. 3:1 offers gear reduction, aka less resistance.

I know that concept will shock most of you and most will say its against the laws of physics. Go try and measure some data. I've seen in the results.

Again, where is your argument? I agree. I am seriously doubting you even attempted to comprehend what I am saying as much as find ways to argue with me. I explained that entire theory you posted basically in the same terms you did and you are arguing with me about it?

Just so its stated on record, you can not change one gear without effecting every other gear. If you make a change to one, you will be forced to change all of the others to keep your RPM drop as it was before.

I agree.

----------------------------------------

So how should one go about calculating gear ratios?

First you need to know a few things.

First, how to use the top speed adjuster. The top speed adjuster need to be used in conjunction with the final drive.

Moving final drive low, numerically, then setting top speed to high, you end up with a starting gear set that will have a really low First gear and a wider 2nd - 6th. I do not recommend this setup.

Moving final drive high, numerically, then setting top speed to high, gives you the net result of all the gears being almost equally spaced. It's easier to tune with set setup.

No matter which way you do it, you will end up with a gear progression between first and 6th that is 75%.

Next you need to realize that N/A and in this game, supercharged cars respond well to lower gear progressions, under 20%. Turbo cars love longer gear progressions, higher then 20%. Take this with a grain of salt though. We're talking 18% vs maybe 22%. That small of a reduction isn't much. I would stray towards shorter gears then long, even in a turbo car.

Your power band is defined from the peak torque RPM to the peak horsepower RPM. When you shift, you should shift 200 RPM after the peak horsepower. Don't just go by the RPM's it gives you, look at the graph. If its flat but giving you the peak value just at the end of a rather flat curve, you can use a different RPM. Common sense.

Longer first and second will translate to shorter 3rd - 6th. Shorter will be faster 90% of the time.

Let's do a quick tune then.....


Set final drive to high numerically and then slide the top speed over. Certain cars will only go so fast, so keep it mind when sliding the top speed over.

Next, take 6th gear and make it has short as possible, high numerically.

Now go test on the track for top speed you need to hit. You should hit your top speed at the end of the power band, NOT THE LIMITER. If it's not where it needs to be adjust the final gear to make the changes you need.

So now your 6th gear and final gear are set. Now lengthen first until the car just starts to bog or it maxed, low numerically. You don't want to bog, but you do not want to bounce the limiter. It should be a clean burn, without hitting the limiter all the way to top speed of first gear. If you maxed out the gear, low numerically, move on and work with second gear to achieve this controlled burn.

Adjust the rest of the gears so the have an equal RPM drop. Having a longer second gear, low numerically is better then leaving it shorter, high numerically.

This will give you the best gearing for a power band period.

So what if the RPM drop is 1000 but my power band is 3000 RPM long? That's good. You can now go through corners and not have to waste a gear shift because you can be within the power band still. It's highly recommended you never shift to first while going around a track. It's just to short for any practical use.

Lets do an example. A car with a 3rd gear ratio of 1.75 and a 4th gear ratio of 1.21

Peak hp 275 @ 7000 RPMs with 8000 rev limiter and is in 3rd gear. But it also has a very angular HP curve so it only makes 250 hp @ 5500 RPMs.

Car makes 265 hp @ 8000 rev limiter.

Should we shift at the rev limiter or 200 RPM past peak hp? Since this car has a linear drop in 1 HP per 100 RPMs, we will call 200 RPMs past 7000 273 horse.

First we absolutely need to know the RPM drop between gears. We cannot figure out anything without knowing this fact. The RPM drop depends on the gearing of the transmission. Lets call it 2000 RPMs at the rev limiter and 1700 RPMs at 7200 shift point. Lets math it out.

Car makes 206.33 TQ @ 7000 RPMs * 3rd gear ratio of 1.75= 361.08 power to wheels (Ignoring final drive)

Car makes 199.14 TQ @ 7200 RPMs * 3rd gear ratio of 1.75 = 348.49 power to wheels (Ignoring final drive)

Car makes 173.97 TQ @ 8000 RPMs * 3rd gear ratio of 1.75 = 304.45 power to wheels (Ignoring final drive)

To make shifting at 7000 RPMs be more beneficial then 8000 RPMs, the car has to be producing more power to the wheels then it would have staying in the same gear for longer.

Citing the 1700 rev drop,

Car will be at 5500 RPMs in 4th gear. The ratio for 4th gear is 1.21

(HP = TQ * RPM / 5252 ) *gear ratio = TQ to wheels.

250 *5252 / 5500 = 238.73 * 1.21 = 288.86

So hold on... By shifting early, we actually have LESS TQ being sent to the wheels then had we run the same car to the rev limiter.

This particular car makes less TQ to the wheels in 4th gear @ 5500 then it did at 3rd gear @ 8000. Therefore, shifting closer to the rev limiter is in fact beneficial. To get the exact numbers, we would need to chart out an excel table like I have advocated in my post to get the exact values in each gear.

 

[Rotary Junkie]

My head. So much text, so much argumentative drivel full of misinformation from both sides.

Anyway, grenadeshark, you didn't mention what I was on about whatsoever.

Route to close-ratio gearing w/ acceptable top speed (results in long 1st gear): Low autoset/top speed slider, numerically low final drive. Best way to set is to find an autoset with a top gear that puts the car in the neighborhood of peak power at top speed. Now adjust 6th gear until you're at peak power when at vmax. Multiply top gear by final drive and divide by the lowest possible setting for final drive (2.000-3.000, 2.500 is common). This is your new top gear (now X). Set maximum speed to minimum, check if you can set top gear to X. If you can't go long enough, increase final by .5, try again, etc etc. If you can't go short enough, do the opposite. Once you find it, do not touch top speed. Set final to minimum, space gears appropriately (I tend to set 1st to just barely spin the tires on a rev-limit clutch drop), done.

More coming eventually/when I feel like it.

 

[grenadeshark]

My head. So much text, so much argumentative drivel full of misinformation from both sides.

Anyway, grenadeshark, you didn't mention what I was on about whatsoever.

Route to close-ratio gearing w/ acceptable top speed (results in long 1st gear): Low autoset/top speed slider, numerically low final drive. Best way to set is to find an autoset with a top gear that puts the car in the neighborhood of peak power at top speed. Now adjust 6th gear until you're at peak power when at vmax. Multiply top gear by final drive and divide by the lowest possible setting for final drive (2.000-3.000, 2.500 is common). This is your new top gear (now X). Set maximum speed to minimum, check if you can set top gear to X. If you can't go long enough, increase final by .5, try again, etc etc. If you can't go short enough, do the opposite. Once you find it, do not touch top speed. Set final to minimum, space gears appropriately (I tend to set 1st to just barely spin the tires on a rev-limit clutch drop), done.

More coming eventually/when I feel like it.

I don't disagree with you on anything you said outside of the fact that close ratio gearing doesn't work for every power curve.

I am not exactly sure where to start as I need to see the results on paper before I can make any statements one way or the other.

I think again though, we are talking tuning techniques vs tuning theory. Once I map this out a bit, I will provide an example that I believe runs counter to this theory if appropriate.

Saying misinformation drivel without any supporting statements is just trash talk.

Edit. Update. Ran out of time for tonight, but here is a basic summary of why your system doesn't always work (granted, no system does).

So I have gone ahead and tested your settings compared to the stock default slider. I did everything exactly as you stated and found that a 1.211 transmission gear ratio in 5th gear got me to my max speed at the peak of my horsepower curve.
The default slider had a 180 setting so I went ahead and used that for comparison sakes. Here is basically what your tuning style accomplishes.

Here is a table of top speeds in each gear and RPM drop to the gear below it.

Default slider at 180
1st 47 mph 5300
2nd 73 mph 5500
3rd 102 mph 6000
4th 137 mph 6100

Your setup.
1st 54 mph 5800
2nd 78 mph 6000
3rd 105 mph 6100
4th 137 mph 6100
--------------------------------------------------
Here is the same basic table with the TQ multipliers being sent to the wheels. (Final gear * trans gear)

Default 180 slider.
1st 47 mph 5300 10.93
2nd 73 mph 5500 7.12
3rd 102 mph 6000 5.05
4th 137 mph 6100 3.8
5th 3.03

Your Setup.
1st 54 mph 5800 9.61
2nd 78 mph 6000 6.68
3rd 105 mph 6100 4.92
4th 137 nog 6100 3.82
5th 3.03

So what does this show us. Basically you have lengthened the first 2 gears of the car (generally a good thing) and left the middle gear about the same. You shortened the gearing on 4th and 5th. But really, in 5th gear you have recreated the default slider exactly.

So what is this gearing good for?

Getting off the line it works quite well. It helps control power in the first 2 gears for any car with power problems down low. Great!

What does this setup not do?

It doesn't do anything for cars that have a peak HP then a very significant drop up to its rev limiter. In those cars, you will be forced to shift constantly and your acceleration will be slowed. Cars with exceptionally long flat HP curves will also not benefit from close gearing.

But GrenadeShark, those kind of cars don't exist in game, do they?

Yes, yes they do.

But GrenadeShark, there are tons of obvious acceleration gains because of this?

I was able to generate a .2 second lead in on s7 using his setup over the default. I equate this mostly to the 5th gear tuning which I did not touch on the default car.

So GrenadeShark, what is the best way to tune the transmission then?

See my post. Every tune needs a basic starting point. I am not saying mine is the best, but I am not not blindly posting methods that are not based on the power curve at all. The method posted above will probably create some gains in most cars. It doesn't mean it's the best way or even an above average way at that.

On a final note, the basic difference between your amazing setup and a stock tune is 1st and 2nd gear. That's basically it. And there is no equating to whether that long of a 1st gear does you any good. On a car with very low amounts of power, that long of a 1st gear will only slow it down due to bogging off the line.

 

[Rotary Junkie]

I don't disagree with you on anything you said outside of the fact that close ratio gearing doesn't work for every power curve.

Didn't say it did. I've run a 4-speed gearbox (that did 300km/h below redline in 4th) with great success before... It always depends on the power curve. Just mentioning that it absolutely cannot be "definitive" without mentioning a way to get pretty much whichever gear spread you wish. Generally it involves playing with the final and top speed setting, the above was detailing using it for close ratios... Wide ratios are a bit simpler unless you also want to eliminate higher gears.

I am not exactly sure where to start as I need to see the results on paper before I can make any statements one way or the other.

Do testing. I've found that the tallest possible final drive (with appropriate ratio selection) results in the fastest acceleration and top speed, both in GT4 and GT5.

I think again though, we are talking tuning techniques vs tuning theory. Once I map this out a bit, I will provide an example that I believe runs counter to this theory if appropriate.

Easy enough to find plenty and it's not a theory, it's a route to get the ratios one wants. Well, it's also a fully applicable theory to those vehicles which benefit from close ratio.

Saying misinformation drivel without any supporting statements is just trash talk.

I apologize for not being in the mood to nitpick over everything. Call it trash talk if you will, I just don't have the willpower to pick apart posts when there are obviously people willing to do it for me (albeit bringing misinformation of their own in).

Edit @ your edit: Actually, that car is one I would DEFINITELY go my route on. Why? More time in the powerband. It's not always best to shift at redline for obvious reasons, particularly with a car like that. Also, shift time is generally minimal (an extra shift hurts a lot less than spending time out of powerband to run wider gearing) so it wouldn't "slow acceleration".

Now then... Xanavi NISMO Z. A car that makes perfect sense to shift at redline (still makes most of its power when bouncing off the limiter) but makes true peak quite a ways before redline. Ideal gearing? Wide enough so that a redline shift drops it about 200rpm before the listed "peak power" stat. I mentioned it (albeit not in name) above.

 

[grenadeshark]

Didn't say it did. I've run a 4-speed gearbox (that did 300km/h below redline in 4th) with great success before... It always depends on the power curve. Just mentioning that it absolutely cannot be "definitive" without mentioning a way to get pretty much whichever gear spread you wish. Generally it involves playing with the final and top speed setting, the above was detailing using it for close ratios... Wide ratios are a bit simpler unless you also want to eliminate higher gears.


Edit @ your edit: Actually, that car is one I would DEFINITELY go my route on. Why? More time in the powerband. It's not always best to shift at redline for obvious reasons, particularly with a car like that. Also, shift time is generally minimal (an extra shift hurts a lot less than spending time out of powerband to run wider gearing) so it wouldn't "slow acceleration".

Now then... Xanavi NISMO Z. A car that makes perfect sense to shift at redline (still makes most of its power when bouncing off the limiter) but makes true peak quite a ways before redline. Ideal gearing? Wide enough so that a redline shift drops it about 200rpm before the listed "peak power" stat. I mentioned it (albeit not in name) above.[/color]

I also posted at the top that it was a work in progress and I would consider any information that I left out.


I actually agree that close gear ratios will help on that car, just not the ones your settings provide! Your RPM drop off leaves the car at too high a RPM in the next gear. We can't drop it to 200 RPM before peak HP because the RPM range is so small for that car. We have to figure out exactly what RPM yields the best TQ ratios and make sure our RPM drops enough to get use out of them. Generic settings just won't do for this car!

 

[Rotary Junkie]

See my post. Every tune needs a basic starting point. I am not saying mine is the best, but I am not not blindly posting methods that are not based on the power curve at all. The method posted above will probably create some gains in most cars. It doesn't mean it's the best way or even an above average way at that.

On a final note, the basic difference between your amazing setup and a stock tune is 1st and 2nd gear. That's basically it. And there is no equating to whether that long of a 1st gear does you any good. On a car with very low amounts of power, that long of a 1st gear will only slow it down due to bogging off the line.

Yay, more to pick apart.

My "amazing setup" works consistently for me. For obvious reasons I vary it depending on the car in question. Low power needs a shorter first to get the correct launch behavior, mad power needs it to be even longer, etc etc etc. There will always be variables but I find this route to work well. You can make the maximum 1st gear stretch further by making the needed top gear ratio be close to the shortest possible rather than longest possible, leading to narrower gears, or lessen it by doing roughly what you did.

I tend to (as mentioned) set my cars up to just barely break the tires loose (and keep them spinning to avoid bogging) after a redline WOT clutch dump and rarely, if ever, spin once underway. Ratios get set as close as is useful. The setup currently sitting on my RX-7 (slight power choke for slightly nicer performance in 535pp rooms) sees me use 1st through 4th at Tsukuba while still maintaining a theoretical top speed above 300 km/h... I make proper use of my ratios rather than wasting the early gears to wheelspin.

Edit:

Urgh. Shift sooner, problem solved. Running that car out to redline is such a massive waste of power I can't even begin to explain it. Same for the extremely power-choked example you have now edited in, shifting at lower RPM will result in faster acceleration. But it'd be even faster for whatever PP it has with fewer power parts and less power choke. Oh, wait, I'm going completely off topic again aren't I... Eyup.

 

[articzap]

We should a gear off. Lol

Choose a car. Preferably leave it stock other transmission and we all create ratios. See which produces fastest lap time.