Transmission Tuning -- top speed vs final ratio

[chuyler1]

Can someone explain the relationship between top speed and final gear ratio?

I have had decent success with lowering the top speed to create tight ratios, followed by lowering the final gear until I get my desired top speed. It usually gives me a tall 1st gear followed by nicely spaced gears for reaching top speed. However, all my cars basically sound like gear whine and its pretty annoying.

I'm wondering if there is a better way and I'm also wondering whether the final gear should be high or low (or if it makes no difference at all in the game).

 

[Lambob]

If I'm not mistaken, the gear whine is a simulated sound, due to the machined straight cut gears, in a "customisable" tranny.

but thanks for the OP, I too am interested to know what final drive and all that jazz means.

 

[CSLACR]

Can someone explain the relationship between top speed and final gear ratio?

I have had decent success with lowering the top speed to create tight ratios, followed by lowering the final gear until I get my desired top speed. It usually gives me a tall 1st gear followed by nicely spaced gears for reaching top speed. However, all my cars basically sound like gear whine and its pretty annoying.

I'm wondering if there is a better way and I'm also wondering whether the final gear should be high or low (or if it makes no difference at all in the game).

Nope, that's the best way, unless you have an awesome power band car. The whine comes with straight-cut gears, and is unavoidable. (one of the realistic sound points for GT games).

Final drive changes the way specific gear ratios affect actual speed.

First gear: 4.000 - This means the gear has to turn 4 times for one engine revolution (RPM)
1.000 means it's dead even with engine RPM.

Final drive, also known as axle ratio, dictates how many revolutions the axle makes for every engine revolution in any gear.

A 4.000 gear must turn 4 times to turn the final drive 1 time, if the final drive must turn 3 times to turn the axle once, this means in first gear, every 12 revolutions of the gear (and engine) makes the wheel rotate one time.

When high gears, 5th, 6th, etc become lower than 1.000, such as 0.882, then the gear turns less than once to rotate the final drive.

This is easier...

In 1st gear, the engine makes 2.97 revolutions for every revolution of the transmission’s output. In 4th gear, the gear ratio of 1:1 means that the engine and the transmission’s output are moving at the same speed. 5th and 6th gears are known as overdrive gears, in which the output of the transmission is revolving faster than the engine.
The Corvette above has a differential ratio of 3.42:1. The ratio means that for every 3.42 revolutions of the transmission’s output, the wheels make one revolution. The differential ratio multiplies with the transmission ratio, so in 1st gear, the engine makes 10.16 revolutions for every revolution of the wheels.
The car’s tires can almost be thought of as a third type of gearing. The example Corvette Z06 is equipped with 295/35-18 tires, which have a circumference of 82.1 inches. This means that for every complete revolution of the wheel, the car travels 82.1 inches. If the Corvette had larger tires, it would travel farther with each revolution of the wheel, which would be like a higher gear. If the car had smaller tires, it would be like a lower gear.
With the gear ratios of the transmission and differential, and the size of the tires, it becomes possible to calculate the speed of the car for a particular gear at a particular engine RPM.
For example, it is possible to determine the distance the car will travel for one revolution of the engine by dividing the circumference of the tire by the combined gear ratio of the transmission and differential.

It is possible to determine a car’s speed from the engine speed by multiplying the circumference of the tire by the engine speed and dividing by the combined gear ratio.

Gear Distance per engine revolution Speed per 1000 RPM
1st gear 8.1 in (210 mm) 7.7 mph (12.4 km/h)
2nd gear 11.6 in (290 mm) 11.0 mph (17.7 km/h)
3rd gear 16.8 in (430 mm) 15.9 mph (25.6 km/h)
4th gear 24.0 in (610 mm) 22.7 mph (36.5 km/h)
5th gear 28.6 in (730 mm) 27.1 mph (43.6 km/h)
6th gear 42.9 in (1,090 mm) 40.6 mph (65.3 km/h)

http://en.wikipedia.org/wiki/Gear_ratio

There's a lot of more complicated things to read there, but this part I quoted is the "layman's terms" I guess.

And you can also learn from the above why changing wheel/tire size can throw off a speedometer as well.

 

[chuyler1]

All that just helps one calculate the top speed given gear ratios, final drive ratios, and tire diameters...something that the game does for you. It doesnt answer my question about whether it is beneficial to run a high final drive or a low final drive. In the end, you end up tuning gears to get the desired rpm at the desired speed...so does it really matter in the game?

Also, is the final drive gear part of the transmission, or is it part of the axle? (in game, not real life)

 

[oppositelock]

I'm not sure I understand your question. The only thing that matters is that trans ratio X final ratio = total ratio. In the case of top speed, running a .500 sixth gear with a 5.000 final is the exact same thing as running a 1.000 sixth with a 2.500 final drive. There's no advantage one way or the other.

 

[AssassinTuner]

I'm not sure I understand your question. The only thing that matters is that trans ratio X final ratio = total ratio. In the case of top speed, running a .500 sixth gear with a 5.000 final is the exact same thing as running a 1.000 sixth with a 2.500 final drive. There's no advantage one way or the other.

X2. In game & reality.

Not everybody thinks so, RJ thinks lower FD values generate more umm "something" I guess, but its "in game" he describes it to having the same effect as lightening the dtive shaft.

Maybe he will chime in and clear it up.

 

[Starfirebird]

I'm not sure I understand your question. The only thing that matters is that trans ratio X final ratio = total ratio. In the case of top speed, running a .500 sixth gear with a 5.000 final is the exact same thing as running a 1.000 sixth with a 2.500 final drive. There's no advantage one way or the other.

I've always seen this in some threads,but never understood how to go about figuring this out.Let me see if i'm understanding some of it.

Trans Ratio is indvidual gear?
Final Ratio is Final Drive?
Then i multiply these 2 together and it should equal out to the total drive?

Total Ratio i'm not sure about how to figure out.

 

[iamjajo]

All that just helps one calculate the top speed given gear ratios, final drive ratios, and tire diameters...something that the game does for you. It doesnt answer my question about whether it is beneficial to run a high final drive or a low final drive. In the end, you end up tuning gears to get the desired rpm at the desired speed...so does it really matter in the game?

Also, is the final drive gear part of the transmission, or is it part of the axle? (in game, not real life)

I do this for my street/production cars:

Cars with a high RPM peak HP get a higher gear ratio

Cars that reach peak HP at low RPM (and maintain a flat band) get a lower gear ratio

I'll typically set the higher one's about 4.11
The lower end is around 3.23

Does it help? Not much, but I've seen some lap time decreases (.10s and .100s). So, it doesn't seem to be a big deal.

My theory is that I want cars with a high RPM peak HP to get to that RPM faster, while cars with a lower peak HP seem to benefit from the lower gears due to the earlier torque.

Others may have a different opinion.

 

[TimberW]

From my experience with the GT5 tuning, top speed affects the top and bottom value of each gear ratio, while final gear doesn't.

I think top speed is a bit like auto tuning.

 

[AssassinTuner]

I've always seen this in some threads,but never understood how to go about figuring this out.Let me see i i'm understanding some of it.

Trans Ratio is indvidual gear?
Final Ratio is Final Drive?

Total Ratio i'm not sure about.

Gear x fd = ratio to 1 revolution of the crankshaft.

Its how many times the crank needs to turn to rotate the wheel once.

For example

3.500 first gear and 4.100 FD =

3.500 x 4.100 = 14.35

So it takes 14.35 revolutions of the crankshaft (or RPM) to turn the wheel 1 time in first gear.

If first gear was 4.100 & the FD was 3.500, the result would be the same.

4.100 x 3.500 = 14.35

IRL its like this, Some think its different in game. Id like to know why they think that and if its true.

 

[Starfirebird]

Gear x fd = ratio to 1 revolution of the crankshaft.

Its how many times the crank needs to turn to rotate the wheel once.

For example

3.500 first gear and 4.100 FD =

3.500 x 4.100 = 14.35

So it takes 14.35 revolutions of the crankshaft (or RPM) to turn the wheel 1 time in first gear.

If first gear was 4.100 & the FD was 3.500, the result would be the same.

4.100 x 3.500 = 14.35

IRL its like this, Some think its different in game. Id like to know why they think that and if its true.

Thanks for the info.

Now i know how to get the Total Ratio.

Now i've got to try and figure out if i'm running the right individual gears that works well with my Final Drive.I can see myself doing this for a while

 

[CSLACR]

All that just helps one calculate the top speed given gear ratios, final drive ratios, and tire diameters...something that the game does for you. It doesnt answer my question about whether it is beneficial to run a high final drive or a low final drive. In the end, you end up tuning gears to get the desired rpm at the desired speed...so does it really matter in the game?

Also, is the final drive gear part of the transmission, or is it part of the axle? (in game, not real life)

4.000 with final of 3.000 Is exactly the same as 3.000 with final 4.000. Yes.
In the game and real life.

I use the "pull top speed down then lower final drive" trick myself, just because that's the only way the game lets you get gears close enough for some cars.
Other than that, there's no difference, you are correct.

I've spent literally hundreds of hours between GT3 and GT4, testing and tuning transmissions. GT5 has the same system (now) so it's exactly the same.

 

[Adrenaline]

Gear x fd = ratio to 1 revolution of the crankshaft.

Its how many times the crank needs to turn to rotate the wheel once.

For example

3.500 first gear and 4.100 FD =

3.500 x 4.100 = 14.35

So it takes 14.35 revolutions of the crankshaft (or RPM) to turn the wheel 1 time in first gear.

If first gear was 4.100 & the FD was 3.500, the result would be the same.

4.100 x 3.500 = 14.35

IRL its like this, Some think its different in game. Id like to know why they think that and if its true.

Take your 2 examples above:
3.500 Final, 4.100 First Gear
vs
4.100 final, 3.500 First Gear
and calculate out the Revolutions of the drive shaft.

Without diving into the actual math, the lower(numerically) final drive gear, requires less rotations of the drive shaft, to arrive at the same amount of rotation at the wheel. The theory, is that since the driveshaft is rotating less, less work is being done by the crankshaft. Less work, less power consumption, less rotating mass = better acceleration or/and more power retained.

This is where the comparison of a 'lighter' driveshaft comes into play.
The motor isn't working as hard to turn the drive shaft, so the theory assumes that more power is being applied(retained I should say) at the rear wheels.

The second part of this theory and the assumption of why it could be modeled in the game, is because of the effects of a 'Carbon Driveshaft' that can be purchased through the Tuning Shop, as well as the 'Lightweight Flywheel'.
Multiple tuners have attested to these upgrades having an effect on the acceleration and deacceleration of a car, directly related to the amount of rotating mass. (Also applies to real world, aluminum flywheels and driveshaft 'spin up' quicker, and also don't deaccelerate as quickly as steel.iron counterparts) So clearly the calculation and active variable inputs for the calculation exist. The next step, is to assume that the game can also account for the rotating mass, of the driveshaft via gear reduction, whether by means of final gear, or transmission gear.

While it may be a stretch, the theory does make sense 'on paper'. Whether or not it actually makes a difference in the game is debatable and furthermore, if it's even measurable or noticeable at any end of the spectrum.

Regardless, the theory appears rather simple.
Less revolutions of the driveshaft = less work = faster acceleration

Whether or not, any of this is accurate, I can not say for sure.
But when I read RJ's description, this is how I interpreted it.
So, apologies to RJ if I misunderstood what he was proposing at the time.
I'd have to go back and find it, to give a more accurate response, the above is just based on my memory of the conversation.

 

[CSLACR]

Take your 2 examples above:
3.500 Final, 4.100 First Gear
vs
4.100 final, 3.500 First Gear
and calculate out the Revolutions of the drive shaft.

Without diving into the actual math, the lower(numerically) final drive gear, requires less rotations of the drive shaft, to arrive at the same amount of rotation at the wheel. The theory, is that since the driveshaft is rotating less, less work is being done by the crankshaft. Less work, less power consumption, less rotating mass = better acceleration or/and more power retained.

This is where the comparison of a 'lighter' driveshaft comes into play.
The motor isn't working as hard to turn the drive shaft, so the theory assumes that more power is being applied(retained I should say) at the rear wheels.

The second part of this theory and the assumption of why it could be modeled in the game, is because of the effects of a 'Carbon Driveshaft' that can be purchased through the Tuning Shop, as well as the 'Lightweight Flywheel'.
Multiple tuners have attested to these upgrades having an effect on the acceleration and deacceleration of a car, directly related to the amount of rotating mass. (Also applies to real world, aluminum flywheels and driveshaft 'spin up' quicker, and also don't deaccelerate as quickly as steel.iron counterparts) So clearly the calculation and active variable inputs for the calculation exist. The next step, is to assume that the game can also account for the rotating mass, of the driveshaft via gear reduction, whether by means of final gear, or transmission gear.

While it may be a stretch, the theory does make sense 'on paper'. Whether or not it actually makes a difference in the game is debatable and furthermore, if it's even measurable or noticeable at any end of the spectrum.

Regardless, the theory appears rather simple.
Less revolutions of the driveshaft = less work = faster acceleration

Whether or not, any of this is accurate, I can not say for sure.
But when I read RJ's description, this is how I interpreted it.
So, apologies to RJ if I misunderstood what he was proposing at the time.
I'd have to go back and find it, to give a more accurate response, the above is just based on my memory of the conversation.

The drive shaft rotates the same amount as the wheel, (with the obvious exception of LSD altering)
No offense, but that blows the whole theory to bits.

The final drive and gears are all in the transmission, and whether 4x3 or 3x4, it's still the same total rotating mass.
One has larger mass on individual gears, one has larger mass for final gear.

Obviously the lighter drivetrain components will put more power to the wheels, but that really has nothing to with whether or not 4x3 is better or worse than 3x4.

I've tested this one aspect of tuning in GT games a lot, including many a personal drag race, (literally thousands) and whether 4x3, 3x4, it was always the same.
I had the exact same questions myself.

 

[Adrenaline]

The drive shaft rotates the same amount as the wheel, (with the obvious exception of LSD altering)
No offense, but that blows the whole theory to bits.

The final drive and gears are all in the transmission, and whether 4x3 or 3x4, it's still the same total rotating mass.
One has larger mass on individual gears, one has larger mass for final gear.

Obviously the lighter drivetrain components will put more power to the wheels, but that really has nothing to with whether or not 4x3 is better or worse than 3x4.

I've tested this one aspect of tuning in GT games a lot, including many a personal drag race, (literally thousands) and whether 4x3, 3x4, it was always the same.
I had the exact same questions myself.

That depends on what you believe the 'Final Drive' represents in the game. (I don't actually know)
I've always assumed it represented a ring and pinion, as in rear end gears, of which are independent of the transmission.
Like when someone swaps out their rear end gears, for 4.10's or 4.56's for drag racing, or how cop cars use 3.55 highway gears and so on.

I could very well be wrong, which is why I've underlined assumed.
I wasn't big into the previous GT games, so my experience is limited to GT5.

 

[CSLACR]

That depends on what you believe the 'Final Drive' represents in the game. (I don't actually know)
I've always assumed it represented a ring and pinion, as in rear end gears, of which are independent of the transmission.
Like when someone swaps out their rear end gears, for 4.10's or 4.56's for drag racing, or how cop cars use 3.55 highway gears and so on.

I could very well be wrong, which is why I've underlined assumed.
I wasn't big into the previous GT games, so my experience is limited to GT5.

Well, you're right, it does represent the rear on RWD.
And just swapping 3.420's (common T-56 RWD) for 3.73's or 4.10's can increase acceleration.
But if one were to alter the individual gears so that the final drive was 4.10 and the gears all made larger to end in the same total (4.100 x 4.000, etc) the mass would be the same.

In other words, if your top speed in 4th gear is 98mph, whether it's a 2.730 final drive or 4.55, you're turning the same mass.

I also learned today, reading the wiki bit, what the hell overdrive really is.
Odd I knew everything else and not that, but such is life.

 

[Adrenaline]

Well, you're right, it does represent the rear on RWD.
And just swapping 3.420's (common T-56 RWD) for 3.73's or 4.10's can increase acceleration.
But if one were to alter the individual gears so that the final drive was 4.10 and the gears all made larger to end in the same total (4.100 x 4.000, etc) the mass would be the same.

In other words, if your top speed in 4th gear is 98mph, whether it's a 2.730 final drive or 4.55, you're turning the same mass.

I also learned today, reading the wiki bit, what the hell overdrive really is.
Odd I knew everything else and not that, but such is life.

The drive shaft doesn't spin at the same speed though. So while the amount of mass remains constant, the amount of times that mass has to rotate changes based on the individual transmission gear. Does that make sense?

Example (Simplified for all to follow, including myself )

You either spin the drive shaft 5 times, or 3 times.
The drive shaft spinning 5 times, turns the ring/pinion 3 times
The drive shaft spinning 3 times, turns the ring/pinion 5 times

The final outcome in both scenarios is '15'

But one of them spins an 80lbs driveshaft 5 times, the other 3 times.
It takes more power to spin an 80lb drive shaft 5 times, than it does to spin a 10lb ring/pinion 5 times. The 'mass' stays the same, but the amount of work required to move that mass, isn't the same between the two scenarios.

Another example, would be...
A human carrying 50 pounds of weight up 1 flight of stairs.
You can carry all 50 pounds in 1 trip, or you can make 5 trips of 10lbs each.
You assume the 'work' is the same in either option, but in actuality, that isn't true.

 

[CSLACR]

The drive shaft doesn't spin at the same speed though. So while the amount of mass remains constant, the amount of times that mass has to rotate changes based on the individual transmission gear. Does that make sense?

Example (Simplified for all to follow, including myself )

You either spin the drive shaft 5 times, or 3 times.
The drive shaft spinning 5 times, turns the Final Drive 3 times
The drive shaft spinning 3 times, turns the Final Drive 5 times

The final outcome in both scenarios is '15'

But one of them spins an 80lbs driveshaft 5 times, the other 3 times.
It takes more power to spin an 80lb drive shaft 5 times, than it does to spin a 10lb ring/pinion 5 times. The 'mass' stays the same, but the amount of work required to move that mass, isn't the same between the two scenarios.

Another example, would be...
A human carrying 50 pounds of weight up 1 flight of stairs.
You can carry all 50 pounds in 1 trip, or you can make 5 trips of 10lbs each.
You assume the 'work' is the same in either option, but in actuality, that isn't true.

But the drive shaft isn't the final drive. The drive shaft takes the power from the gear back to the final drive.

Example (Simplified for all to follow, including myself )

You either spin the drive shaft 5 times, or 3 times.
The drive shaft spinning 5 times, turns the Final Drive 3 times
The drive shaft spinning 3 times, turns the Final Drive 5 times

The final outcome in both scenarios is '15'

So yes, long individual gears with a short final drive will spin your drive shaft less.

But for weight comparisons, you need to add the extra gear weight, and the entire axle weight, along with hubs, wheels and tires, and rotors, then measure that against the drive shaft's weight.

So Drive shaft weight
Vs.
Gear, axle, hubs, rotors, wheels, and tires.

I honestly don't think there's a difference that's noticeable, but what you were told is exactly backwards, I assume because it was based on the mis-information that the final drive is the drive shaft.

Edit: If anything, I'd venture a guess the gear, axle, hubs, rotors, wheels, & tires weigh more.
Mostly because of the axle, and the entire hub, etc.

But it makes a strong argument why high-performance cars have long final drives.

 

[Adrenaline]

But the drive shaft isn't the final drive. The drive shaft takes the power from the gear back to the final drive.

So yes, long individual gears with a short final drive will spin your drive shaft less.

But for weight comparisons, you need to add the extra gear weight, and the entire axle weight, along with hubs, wheels and tires, and rotors, then measure that against the drive shaft's weight.

So Drive shaft weight
Vs.
Gear, axle, hubs, rotors, wheels, and tires.

I honestly don't think there's a difference that's noticeable, but what you were told is exactly backwards, I assume because it was based on the mis-information that the final drive is the drive shaft.

Edit: If anything, I'd venture a guess the gear, axle, hubs, rotors, wheels, & tires weigh more.
Mostly because of the axle, and the entire hub, etc.

Umm... No?

The axles, hubs, rotors, wheels and tires spin the exact same in both scenarios.
That's the "total" of 15 in the example I used.

The theory I'm currently discussing, is that the 'final drive' in GT5, refers to the Rear End gear, specifically the ring & pinion.

The Constant in the equation is the Tire Speed; 1 Revolution of the tire.
The question, is whether turning the driveshaft X times, and the pinion/ring Y times, is more or less work than turning the driveshaft Y times and the pinion/ring X times, when the assumed outcome is 1 revolution of the tire, in both possibilities.

 

[CSLACR]

Umm... No?

The axles, hubs, rotors, wheels and tires spin the exact same in both scenarios.
That's the "total" of 15 in the example I used.

The theory I'm currently discussing, is that the 'final drive' in GT5, refers to the Rear End gear, specifically the ring & pinion.

The Constant in the equation is the Tire Speed; 1 Revolution of the tire.
The question, is whether turning the driveshaft X times, and the pinion/ring Y times, is more or less work than turning the driveshaft Y times and the pinion/ring X times, when the assumed outcome is 1 revolution of the tire, in both possibilities.

Yes, you're right, I'm tired, even more now than I was then.

Final drive in RWD is the rear, yes, but just changing the final drive has no effect on the drive shaft's revolutions.

So mathematically, yes, a higher (quicker) final drive could result in slightly more power at the wheels, though it's hard to say by how much, and adding a lightweight drive shaft would actually lessen the gain vs a longer final drive with quicker gears.

It would be interesting to see a real world test on this.

 

[Rotary Junkie]

Yes, you're right, I'm tired, even more now than I was then.

Final drive in RWD is the rear, yes, but just changing the final drive has no effect on the drive shaft's revolutions.

Final drive in any vehicle using a driveshaft which goes to the differential is the ratio @ said differential.

The driveshaft is, in these cases (FR save Corvette etc which have a rear-mounted transaxle and a torque tube that spins @ engine RPM instead of transmission output RPM, FAWD, MAWD, RAWD) spinning at the same speed as the transmission output shaft but faster than the axle shafts and wheels. A numerically higher final drive will result in a higher driveshaft speed at a given wheel speed (as well as higher engine/trans speeds).

As for a set of 3.73s or 4.10s "increasing acceleration"... Well, yes and no. The shorter diff gear will help if there is enough traction to take advantage of the added wheel torque in 1st gear but it won't help acceleration any past that... And depending on the speed range it may add an extra shift. Most factory transmissions are also somewhat poorly spaced between 1st and 2nd gear (large drop), so a shorter diff ratio will get the car higher into 2nd "sooner" and keep the engine closer to its "happy place" for a longer duration down track.

Now, since a transmission regear is expensive and time consuming (particularly in comparison to a ring & pinion swap) you won't see people in the real world running a set of 2.73s and a 3.48 first gear instead of a "normal" T56 and 3.42s. There's also another reason in the real world to avoid high transmission multiplication in a normal manual transmission... Case stress. More multiplication in a manual transmission will exert more outward force on the transmission's gears for a given input torque... Too much of that and suddenly you've split the case.

Nom nom nom, enough off topic. Chuyler, my point of view on it is to run the absolute tallest (numerically low) final drive as you can and compensate with numerically higher transmission ratios. It definitely helps acceleration in-game (and would in the real world if it were remotely practical) and is how all the cool kids in the drag rooms do it. And how my RX-7 cracked into the 8.0 1/4 mile range in GT4.

 

[XDesperado67]

Nom nom nom, enough off topic. Chuyler, my point of view on it is to run the absolute tallest (numerically low) final drive as you can and compensate with numerically higher transmission ratios. It definitely helps acceleration in-game (and would in the real world if it were remotely practical) and is how all the cool kids in the drag rooms do it. And how my RX-7 cracked into the 8.0 1/4 mile range in GT4.

Thanks RJ this won't create a "perfect" transmission setup for me but should greatly improve my cars performance.

Do you suggest using the smallest final available or limiting the final gear to regulate top speed to what the car can actually achive on a given track?

 

[chuyler1]

Alright, I think my question has been answered. RJ and a few others have lots of luck with running the lowest final drive possible. Even if it doesn't make a difference, it does allow you to run closer ratios for the individual gears....and it's the only way to get a really tall 1st gear.

All the other calculations are moot as far as I'm concerned. I tune gears based on rpms and shift points. Using the supplied torque curve, I decide when i want to shift, and I tune the gears so that shifting falls within the power band. Usually the low-top-speed trick is sufficient for gears 1-5 and then its just a matter of tweaking 6th for drafting.

It also sounds like getting rid of gear whine is impossible. Whether I run a high final drive or low final drive the transmission will sound the same right?

 

[esoxhntr]

Chuyler, you need to tune your individual gear ratios for the powerband of the vehicle. Once that is done, you should never touch the individual gears again (unless you really want to get picky and tune for a specific corner on a track or adjust 1st gear for an optimal launch on different tires or you changed the PP/HP). You use the final drive to adjust for the top speed for the track. The amount of RPM drop will always remain the same between the gears no matter what you do to the FD and you are sure to make the most use of a car's available power.

That is a simple as I can put it.

You will want longer (more spacing) gears for cars with a fat powerband to take advantage of the power available over a broad RPM range. So, broad powerband = longer (lower indiividual ratios) gears, higher FD is the end result.

For cars with a narrow power curve the opposite is true. You don't want a big RPM drop between gears. So, Tightly spaced gears (higher individual ratios), lower FD is the end result.

power to the wheels = torque * gear ratio * final drive.

100 * 2 * 4 is the same as 100 * 4 * 2. You just need to understand when to use one over the other.

 

[chuyler1]

Yeah, I've got all that osprey...and I think I'm pretty good at setting it up since I never have a problem on same-make night with acceleration. I was just wondering whether there was advantage to running higher vs lower final drive given the same final output ratios.

 

[AssassinTuner]

So to be clear, RJ you say this

Is faster than this

?


I've taken a gear set and recalculated it with the lowest available FD value, then recalculated it with the highest available FD value.

I put together a quick convertor that will do it to any gear set you want to test.

Are we on the same page as far as your Theory? It would be interesting if it were to show a difference.

I would suggest people look before they leap. It very well may be GT5 uses the FD to adjust rolling resistance between gears. RJ's theory (at least in GT5, we cant test as easy IRL) has been disproven, but sinse this is a program things may not always be as they appear or are IRL.

 

[dr_slump]

S
I've taken a gear set and recalculated it with the lowest available FD value, then recalculated it with the highest available FD value.

I put together a quick convertor that will do it to any gear set you want to test.

Are we on the same page as far as your Theory? It would be interesting if it were to show a difference.

No, what he wants to say is that a lower FD allows you to set the gears closer and that with the same top speed.

 

[AssassinTuner]

No, what he wants to say is that a lower FD allows you to set the gears closer and that with the same top speed.

I can get any ratio he can get with a 3.000 FD with a 6.000 FD. They get the same top speed.

It makes no difference at all.

 

[dr_slump]

I can get any ratio he can get with a 3.000 FD with a 6.000 FD. They get the same top speed.

It makes no difference at all.

Forget this stupid top speed! I said: "with the same top speed!" (Hard to understand?)
GT5 transmissions have a limited range of gear ratios. This FD thing is the only way to set the gears as close as possible. If you still don't believe me, I can give you an example of a super close transmission.

 

[AssassinTuner]

Forget this stupid top speed! I said: "with the same top speed!" (Hard to understand?)
GT5 transmissions have a limited range of gear ratios. This FD thing is the only way to set the gears as close as possible. If you still don't believe me, I can give you an example of a super close transmission.

Same top speed. I understood and proved it and RJ's Therory in GT5 wrong.

Here is the proof

Example A lowest FD value

Example B highest FD value

These 2 gear sets have the exact same everything except gears and fd values. One calculated with the lowest availible fd value, the other the highest. I even use the same top speed tuner setting.

Everything is the same (I confirm that GT5 does not use fd to adjust RR) there is absolutly no difference.


PLEASE show me a gear set you can get with a 3.000 FD value, ill show you it recalculated with a 6.000 and it will perform the same, top speed and all...

I say again, people need to look before they leap. Some things just may be placebo.