"tranny trick" debunked 2.0

[nomis3613]

...continuing a thread closed 5 years ago...

I always thought the "tranny trick" was just a shortcut method used by people who don't know how to tune gears properly. But after a bit of reading and testing, it seems there is something behind it after all.

In real life (and, I believe, in GT4), the number which matters is each individual gear ratio multiplied by the final drive. The Auto Setting is just a shortcut way of changing the gear ratios. No matter where the final drive is set, if you adjust the Auto Setting to the same value, the tallest possible gear ( =lower limit of 6th gear slider x final drive ratio) is always the same. In other words, GT4 automatically compensates for the current Final Drive, so that Auto Setting will produce the same overall gearing every time, regardless of anything else. I'm second-guessing Polyphony here, but this leads me to think that the Auto Setting was included to allow novices to easily get a decent set of gear ratios 1) without having to change all the sliders individually and 2) without worrying about the interaction of the Final Drive setting.
(or it could just be that the Auto Setting is a way to set the range of the individual gear ratios, but the fact that the "tranny trick" exists kind of favours the "novice 1 setting only" theory. Don't worry, this should make sense later on!)

However, it is still possible to change the Final Drive after the Auto Setting. And this is how the tranny tick comes in. The Auto Setting changes the possible adjustment range for the individual gears, so when combined this with the Final Drive, this gives you gear ratios that are not possible without using this trick.
Example #1: in the Suzuki GSX-R/4 by setting the final drive to minimum, then putting Auto Setting all the way left (to make all the gear ratios shorter), then finally moving the Final Drive to maximum (shortening ratios), the gearing was so short that the maximum speed in 6th gear was 95km/h!
Example #2: set the final drive to maximum, Auto Setting all the way right, then final drive to minimum and you find the gears are so tall that it will pull 160km/h in 1st gear!! Neither of these setups are useful for racing, but at least they demonstrate how the Auto Setting can be used.

So is there a "tranny trick" where just the Auto Setting then the Final Drive are changed and a magic set of gear ratios is generated? NO WAY! Gear tuning is a complex compromise, if the traditional "tranny trick" results in the optimum gear ratios for a given car on a given track, this is just a fluke.

The real "Auto Setting Bug" is that clever GT4 gearing tuners can use the Auto Adjust setting (to changing the range of adjustment) in situations where individual gear ratios normally can't be set high/low enough to achieve the desired effect.

Feel free to question/challenge/comment!

 

[Parnelli Bone]

Actually, lots of tuners here have used the tranny trick, lots of experienced tuners that is. I would assume most novices don't even know what it is, and if they do, they don't understand how it works and why.

It's just a fancy way of obtaining a desired result, really.

 

[mafia_boy]

Beware, you have now stepped into very familiar territory, so prepare for a BIG challenge.

...continuing a thread closed 5 years ago...

I always thought the "tranny trick" was just a shortcut method used by people who don't know how to tune gears properly. But after a bit of reading and testing, it seems there is something behind it after all.

In real life (and, I believe, in GT4), the number which matters is each individual gear ratio multiplied by the final drive. The Auto Setting is just a shortcut way of changing the gear ratios. No matter where the final drive is set, if you adjust the Auto Setting to the same value, the tallest possible gear ( =lower limit of 6th gear slider x final drive ratio) is always the same. In other words, GT4 automatically compensates for the current Final Drive, so that Auto Setting will produce the same overall gearing every time, regardless of anything else. I'm second-guessing Polyphony here, but this leads me to think that the Auto Setting was included to allow novices to easily get a decent set of gear ratios 1) without having to change all the sliders individually and 2) without worrying about the interaction of the Final Drive setting.
(or it could just be that the Auto Setting is a way to set the range of the individual gear ratios, but the fact that the "tranny trick" exists kind of favours the "novice 1 setting only" theory. Don't worry, this should make sense later on!)

However, it is still possible to change the Final Drive after the Auto Setting. And this is how the tranny tick comes in. The Auto Setting changes the possible adjustment range for the individual gears, so when combined this with the Final Drive, this gives you gear ratios that are not possible without using this trick.
Example #1: in the Suzuki GSX-R/4 by setting the final drive to minimum, then putting Auto Setting all the way left (to make all the gear ratios shorter), then finally moving the Final Drive to maximum (shortening ratios), the gearing was so short that the maximum speed in 6th gear was 95km/h!
Example #2: set the final drive to maximum, Auto Setting all the way right, then final drive to minimum and you find the gears are so tall that it will pull 160km/h in 1st gear!! Neither of these setups are useful for racing, but at least they demonstrate how the Auto Setting can be used.

So is there a "tranny trick" where just the Auto Setting then the Final Drive are changed and a magic set of gear ratios is generated? NO WAY! Gear tuning is a complex compromise, if the traditional "tranny trick" results in the optimum gear ratios for a given car on a given track, this is just a fluke.

The real "Auto Setting Bug" is that clever GT4 gearing tuners can use the Auto Adjust setting (to changing the range of adjustment) in situations where individual gear ratios normally can't be set high/low enough to achieve the desired effect.

Feel free to question/challenge/comment!

You've misconstrued what the "tranny trick" truly is, and this has been debated before by several people. There are two methods to doing this but only consider one to be the right way which I'll explain.

The first is as you've described, work out your best auto setting, adjust gears then adjust the final ratio. So you work out your best range from your auto setting, then adjust like you want then move the final ratio after you change the gear ratios but DO NOT touch the auto set again. This is sometimes called a "tranny trick" but it's not.

The second is what other tuners and I use which is what the tranny trick truly is, and it's a slightly more difficult but more precise method of gearbox tuning. What you do FIRST is to move the final ratio to it's "lowest" setting (now when I say a low setting, I'm meaning low ratio.....so for example a final ratio of 4.750 is low, and one with 3.750 is high, that's how it's discussed). For most of my cars, this means taking it to 5.500 and in some cases, 6.000. I then adjust the autoset AFTER this. What it will do is provide you with some SUPER CLOSE ratio gears. And when I say super-close, I really mean super-close......closer than you will EVER get with the first method. Then, you set your individual ratios, THEN set the final ratio and once again, DO NOT TOUCH THE AUTO SET AFTER THAT!!

All of my cars in Grease Monkey Engineering follow this second method and it's been successful for me.....but others haven't grasped it as well as the known tuners on this site. Very rarely will I need to start off with the final ratio NOT at it's lowest setting.....like putting it at 5.000 rather than 5.500, but it has happened......my 400km/h FF's are evidence of that.

I hope that paints a better picture for you Nomis. 👍

 

[nomis3613]

@Parnelli and mafs

Thanks for the replies! Yeah, from the posts I read, I had assumed that the "tranny trick" was a method to get all perfect ratios at once, without having to tweak each separate ratio. This, I'm sure you'll agree, doesn't work! (except for top speed challenges)

Cool, sounds like what mafia_boy is describing is the same method as I used to get the GSX-R/4 to top out at 95km/h in 6th (ok, this gear set might be slightly too short...)

 

[Rotary Junkie]

I use this in a few ways...

One is to optimize acceleration with FR and AWD vehicles; adjust the final drive until autoset 1 gives you a top gear ratio that will fulfill your targeted overall ratio with a final of 2.500; the taller the final gear, the less RPM the driveshaft turns, resulting in a "lightweight driveshaft" effect. I believe the last I truly tested this was with an Impreza Coupe R; I found the "overall" ratios for each gear (gear x final) then divided each by 2.5, found an auto setting that allowed the "new" ratios, set final to 2.5, and it saved .3 sec on 400m tests.

The second is simply to find a "realistic" ratio set, at times it's impossible to get a given set from the basic auto settings + gear adjustment even if it was the factory ratio set.

 

[Sniffs]

sounds like you guys made everything extremely complicated for setting your gear ratios, etc to your personal ideal spot. i came up with a simple solution: 1/5th, 1/4th, 1/3rd. since the original thread is a closed five year old, I doubt very much i got the chance to post in it. I've been using the 1/5th method when I dig up GT4, since a lot of the tracks are hyper twisty for my comfort.

 

[mafia_boy]

It's not complicated sniffs, it's a case of learning how to do it and once you do, it becomes very very easy to achieve in all of your cars and provides a very smooth gearbox, with the addition of increasing your top speed overall and reducing your acceleration times without any detriment to the drivability of the car.

Nomis - It's similar, except that I bring the final ratio BACK to what it was originally set as I said in my previous post. So for example, the DC5 Integra Type R has a standard final ratio somewhere in the 4.8's from memory, so it can get to 6.000 for it's final then get brought back to the 4.8 area after you've found your gearset then tuned your gears.

RJ's method works aswell but he's explaining it in a more complicated manner.

 

[nomis3613]

Thanks mafia_boy and RJ. This "shorter Final Drive = less drivetrain inertia" theory sounds really interesting. I'll be back soon with some 400m test results...

 

[mafia_boy]

If you want to test the full gearbox (ie. 1st through to 5th/6th/7th, depending on car) then it's best to take it to the 1000m track on the test course. 👍

 

[nomis3613]

True, but the effect should be present in the lower gears too. At higher speeds, it might be less noticeable as other factors become more important (aero etc) so I think the 400m test would more clearly show if the effect existed or not.

 

[mafia_boy]

No, because some cars such as the Impreza Spec C can pull all the way to 320km/h+ without a worry within 1000m without nitrous and over 400km/h with nitrous and can actually increase the difference between both gear sets compared to a 400m run. Cars like the R35 GT-R Proto use all 7 gears within 400m when used with nitrous, so it's very subjective as to what your bases are.

Remember, when we are talking about 400m/1000m things, we usually incorporate nitrous into the equation. However I can tell you for certain that the RX7 Bathurst R ran a 9.750 without nitrous over 400m, and ran an 8.235 with it in my hands. It has been faster with nitrous in MadMax86's hands though, and with a stock gearset I was just into the 9's without nitrous and doing 8.3's & 8.4's with the factory gears.

Have a fiddle around with the ratios because I found my suitable setup would be to increase top end without affecting acceleration so I could pull to higher speeds with the same ferocity as I would've with the factory set without any worry of hitting a rev limiter, and to achieve this higher top speed in the same space of time and distance but still be very high in the rev range in top gear when doing max speed tests without it hitting the limiter.

 

[Sniffs]

I must be the only one that doesn't bother with the nitrous (I think that's cheating, personally). course, i concentrate more on handling and (when it comes to tranny settings) making sure I can zip ahead of, and keep ahead of the Speed Demon the cheating computer AI inevitably slips into the race

if you guys have usable formula set I can apply to the Cuda (which, no matter what I do, can't keep up), I'd appreciate it.

 

[boiltheocean]

I would assume most novices don't even know what it is.

This. I'm one below a novice(as in I've never tuned in my life) and I always thought a tranny trick is something you didn't want to run into at a bar.

 

[mafia_boy]

@ sweetshop. That's only in Thailand.

sniffs - I ONLY use nitrous for the 400m/1000m/max speed tests and that is it. Now, which series are you trying to do and what are the specs of your 'cuda?? Like, what modifications have you already got? I'm sure there's more than 1 of us that can tailor a gearbox to make it work for that car if it already hasn't been done.

Actually, it already has......run the setup from MFT.

Plymouth Barracuda 440-6 w/ 740hp!!

That should help you out. 👍

 

[nomis3613]

Hi, I'm not sure I understand your reply but here goes...

No, because some cars such as the Impreza Spec C can pull all the way to 320km/h+ without a worry within 1000m without nitrous and over 400km/h with nitrous and can actually increase the difference between both gear sets compared to a 400m run. Cars like the R35 GT-R Proto use all 7 gears within 400m when used with nitrous, so it's very subjective as to what your bases are.

Fair enough, I chose not to use nitrous cos I was worried it would be less consistent (haven't tested whether this is true or not, so better safe than sorry for the moment).

Have a fiddle around with the ratios because I found my suitable setup would be to increase top end without affecting acceleration so I could pull to higher speeds with the same ferocity as I would've with the factory set without any worry of hitting a rev limiter, and to achieve this higher top speed in the same space of time and distance but still be very high in the rev range in top gear when doing max speed tests without it hitting the limiter.

Sorry, I don't understand how this relates to the "tranny trick"? Could you explain please (I'm not very familiar with drag racing if this is what you're talking about)?

Anyway, I did a couple of 400m tests using a 553kW Evo VII on Racing Super Soft tyres (to minimise wheelspin so results would be more consistent). With these ratios (1st/2nd/.../6th/final drive):
2.570 / 1.880 / 1.440 / 1.150 / 0.950 / 0.780 / 4.550
my two runs were both exactly 10.553 (off-topic, but I found that 4.55 gave the best times because if the ratio was shorter then the engine hit the rev limiter before shifting to 2nd)
Then, using the same ratios at the wheels, but achieved with a 34% shorter diff
3.898 / 2.852 / 2.184 / 1.745 / 1.441 / 1.183 / 3.000
the two runs were 10.548

So it is true! Running taller 1st to 6th ratios and a shorter diff does improve acceleration for some reason. Of course 0.005 seconds improvement over 0-400m is insignificant for a circuit setup, but I also noticed that this method also allows a tighter spread between the higher gears (because of how the possible ranges in gear ratios changes). Are either of these effects the "tranny trick" perhaps?

Thanks,
Simon

 

[mafia_boy]

Hi, I'm not sure I understand your reply but here goes...

Fair enough, I chose not to use nitrous cos I was worried it would be less consistent (haven't tested whether this is true or not, so better safe than sorry for the moment).

Fair enough, would be best if you did so. 👍

Sorry, I don't understand how this relates to the "tranny trick"? Could you explain please (I'm not very familiar with drag racing if this is what you're talking about)?

I wasn't doing it for drag racing, I'm talking about setting your car up for ultimate performance in both acceleration and top speed. By using the tranny trick (ie. high 1st through 6th), you can shorten the gear ratios between each gear as you've just discovered in the paragraph below which allows the motor to stay in it's powerband more consistently. But because the 5th/6th gears are ultimately higher, you will inevitably wind up with a higher top speed aswell as a result of this, making it a win/win situation. Just don't make the gearing too high otherwise you won't be able to accelerate in those gears.

Anyway, I did a couple of 400m tests using a 553kW Evo VII on Racing Super Soft tyres (to minimise wheelspin so results would be more consistent). With these ratios (1st/2nd/.../6th/final drive):
2.570 / 1.880 / 1.440 / 1.150 / 0.950 / 0.780 / 4.550
my two runs were both exactly 10.553 (off-topic, but I found that 4.55 gave the best times because if the ratio was shorter then the engine hit the rev limiter before shifting to 2nd)
Then, using the same ratios at the wheels, but achieved with a 34% shorter diff
3.898 / 2.852 / 2.184 / 1.745 / 1.441 / 1.183 / 3.000
the two runs were 10.548

So it is true! Running taller 1st to 6th ratios and a shorter diff does improve acceleration for some reason. Of course 0.005 seconds improvement over 0-400m is insignificant for a circuit setup, but I also noticed that this method also allows a tighter spread between the higher gears (because of how the possible ranges in gear ratios changes). Are either of these effects the "tranny trick" perhaps?

That is the effect of the tranny trick, to have a tighter spread between the gears that would otherwise not be possible with any general autoset fiddling. What this also does is allow you to bring a taller first gear to maximise grip on your takeoff with high powered cars. If the ratio is too low, the engine will overpower the tyres due to the driveline multiplying the torque too much. A higher ratio reduces this.

 

[MadMax]

Remember, when we are talking about 400m/1000m things, we usually incorporate nitrous into the equation. However I can tell you for certain that the RX7 Bathurst R ran a 9.750 without nitrous over 400m, and ran an 8.235 with it in my hands. It has been faster with nitrous in MadMax86's hands though, and with a stock gearset I was just into the 9's without nitrous and doing 8.3's & 8.4's with the factory gears.

Thanks for reminding me Mafs 👍

The 3rd use of Tranny Trick , which can turn normal gear box in to 2 set of gears / exeed the limits of final drive by about 0.100

I will return to write about this.



MadMax

 

[Parnelli Bone]

This. I'm one below a novice(as in I've never tuned in my life) and I always thought a tranny trick is something you didn't want to run into at a bar.

har har...somebody's gotta be the comedian always.

I must be the only one that doesn't bother with the nitrous (I think that's cheating, personally). course, i concentrate more on handling and (when it comes to tranny settings) making sure I can zip ahead of, and keep ahead of the Speed Demon the cheating computer AI inevitably slips into the race

Nitrous is cheating only during races in which not every car is using nitrous. In other words, if the race specifies nitrous can be used, then it's okay. But I would agree that using nitrous against the computer definitely is cheating because the Ai never uses it.

On the other hand, I have used nitrous on occasion during races in which the Ai is extremely agro. I figure if THEY can cheat by ramming me and trying to spin me and stuff, I get to cheat back (if I have to) by tapping some extra speed.

 

[Rotary Junkie]

Simon: That's a MUCH smaller improvement than I'm used to seeing, perhaps because the Evos are FWD-based AWD? Try the same thing on a Subaru or a full-on RWD car and report back if you could.

 

[mafia_boy]

RJ, if he hasn't used the other things such as ballast, etc. then a 10.3 sounds about right for me.

Nomis, just curious.....are you using any ballast or any other tricks of the trade and what's your suspension at, default or a tuned setup?

 

[Rotary Junkie]

Mafs, I did my testing with a 375hp or so Impreza Coupe R and I gained .3 on the 400m drag, factory FC ratios versus the same overall ratios with a 2.500 final drive.

Which, IMO, is a very noteworthy improvement, however it still didn't make up for the parasitic losses versus an FD of the same weight and power.

 

[niky]

Man... haven't used this in ages... haven't played GT4 in ages.

Used to use the tranny trick all the time... great way to get close ratios... it's difficult to impossible to get the same kind of ratios manually without doing it.

Still, not really a necessary tool in your arsenal against the AI... they're arbitrarily locked in to 85-90% speed, anyway. But if we get the same kind of control in GT5, with online races, I'm going to have to learn it all over again...

Proper tranny tuning helped me get some of the worse cars into competitive shape for online races in GT5P... though the lack of custom gearboxes and the overall PP limit meant that my Integra was never going to be a winner in Daytona Road Course Professional 550PP races... but I have annoyed quite a few people by keeping in touch with them everywhere but the straights...

 

[nomis3613]

(re nitrous for consistent 400m results)

Fair enough, would be best if you did so. 👍

Will do. Even as I typed my last post I was thinking "I should really stop being lazy and just test it"!

By using the tranny trick (ie. high 1st through 6th), you can shorten the gear ratios between each gear as you've just discovered in the paragraph

Actually, my testing was done with identical overall ratios each time. The only difference was that one way had higher individual ratios and a lower diff ratio (basically testing if having the driveshaft sprinning at higher speed caused extra inertia).

But because the 5th/6th gears are ultimately higher, you will inevitably wind up with a higher top speed aswell as a result of this, making it a win/win situation. Just don't make the gearing too high otherwise you won't be able to accelerate in those gears.

totally agree!

Simon: That's a MUCH smaller improvement than I'm used to seeing, perhaps because the Evos are FWD-based AWD? Try the same thing on a Subaru or a full-on RWD car and report back if you could.

Sure. I'll try that.

Nomis, just curious.....are you using any ballast or any other tricks of the trade and what's your suspension at, default or a tuned setup?

No ballast. FC suspension, LSD with some random settings- wasn't really paying attention, cos I didn't think it would affect the comparison of gear ratios vs FD ratio?

 

[nomis3613]

Some testing results to follow up my last post.

Firstly I tested whether using nitrous causes inconsistent 400m times. It doesn't- 2 runs using Nitrous resulted in exactly the same time. Thanks, mafia_boy!

Now, back to the "tranny trick". Rotary_Junkie suggested I try the tests with an RWD car to see if that gives a greater difference. So I jumped in a RX-7 with about 550kw (can't remember exactly how much) running R5 tyres. I wanted to test using nitrous, but it was too hard finding a setup that didn't hit the rev limiter in 1st, so I ended up not using nitrous.

Baseline test with these ratios (1st/2nd/.../6th/final drive)
4.00/2.85/2.00/1.47/1.14/1.07 / 3.8
time: 10.730

Then using a 3.0 diff ratio and using the "tranny trick" to get the same overall ratios (eg multiplying each gear by 1.267).
time: 10.715

So, yeah, there is 3 times greater effect for the rwd RX-7 than the 4wd Evo II (0.015 vs 0.005 quicker). 0.015s is still a small increase in the grand scheme of things, though.

But then things got strange. The above tests were done without the Carbon Driveshaft installed (I was thinking that a heavier driveshaft would maximise the effect of the "tranny trick" in reducing drivetrain inertia). So then I repeated the tests with the Carbon Driveshaft
without tranny trick (ie 3.8 fd ratio): 10.687
with tranny trick (ie 3.0 fd ratio): 10.661

0.026s difference. So the lighter Carbon Driveshaft actually increases the effect of the tranny trick. Why???

 

[Rotary Junkie]

Well, another thing to consider is that the more power you have, the easier it is to overcome the inertia.

I'm going to fire up GT4 myself and do a few tests, will edit.

Testing being done with 262hp AP1 S2000 with S3 tires. Default gearing is:

[3.635/2.479/1.823/1.405/1.135/0.960], final of 4.100.

Set final to 3.650, autoset to 1, gear settings of:

[5.961/4.066/2.990/2.304/N/A/1.5744 (5th is not quite available, settings not available tall enough and I didn't feel like fiddling more), final of 2.500. Inconsistency there is a non-issue as 1/4 mile only uses 1st through 4th in this case.

With CF driveshaft:
13.740
13.617

Without:
13.846
13.707

Although, could it be that the final being set to 3.000 instead of 2.500 is making that large of a difference? I'll do more test work when I'm not dead.

 

[nomis3613]

Thanks for sharing your results. Sorry if this is a stupid question...but...

With CF driveshaft:
13.740
13.617

Is 13.740 with tranny trick and 13.617 is without? Or are they 2 runs with the same setup?

If they are with and without tranny trick, then they are the opposite of my results (CF driveshaft decreases effect of tranny trick), but they are actually what I was expecting.👍

 

[Rotary Junkie]

Yes, top number is non-tricked gearing and bottom is tricked.

Used automatic transmission for consistency's sake (WOT launch and AT = exactly the same numbers every time).

 

[nomis3613]

Yes, top number is non-tricked gearing and bottom is tricked.

Used automatic transmission for consistency's sake (WOT launch and AT = exactly the same numbers every time).

Cool! That's the same technique I use.

I wonder why Polyphony made it that on some cars the CF driveshaft increases the tranny trick effect, but on others it decreases it? <scratches head>

 

[mafia_boy]

Mafs, I did my testing with a 375hp or so Impreza Coupe R and I gained .3 on the 400m drag, factory FC ratios versus the same overall ratios with a 2.500 final drive.

Which, IMO, is a very noteworthy improvement, however it still didn't make up for the parasitic losses versus an FD of the same weight and power.

So, the only change you made was the final drive and left all the individual gears alone, am I correct with that RJ?

Actually, my testing was done with identical overall ratios each time. The only difference was that one way had higher individual ratios and a lower diff ratio (basically testing if having the driveshaft sprinning at higher speed caused extra inertia).

That's a big difference. You need to test different individual gearsets with the same final ratio. That's why I mentioned my method of reverting back to the stock final ratio after I tune my gearbox.

No ballast. FC suspension, LSD with some random settings- wasn't really paying attention, cos I didn't think it would affect the comparison of gear ratios vs FD ratio?

It doesn't to a degree, but having certain settings allows more consistency. For example, I usually run an LSD setting of 40/60/5 which allows good grip on takeoff, full acceleration with no deviations from the wheels and a minimal reduction of speed.

Some testing results to follow up my last post.

Firstly I tested whether using nitrous causes inconsistent 400m times. It doesn't- 2 runs using Nitrous resulted in exactly the same time. Thanks, mafia_boy!

See, I told you to try nitrous.

Now, back to the "tranny trick". Rotary_Junkie suggested I try the tests with an RWD car to see if that gives a greater difference. So I jumped in a RX-7 with about 550kw (can't remember exactly how much) running R5 tyres. I wanted to test using nitrous, but it was too hard finding a setup that didn't hit the rev limiter in 1st, so I ended up not using nitrous.

Baseline test with these ratios (1st/2nd/.../6th/final drive)
4.00/2.85/2.00/1.47/1.14/1.07 / 3.8
time: 10.730

Then using a 3.0 diff ratio and using the "tranny trick" to get the same overall ratios (eg multiplying each gear by 1.267).
time: 10.715

Were the individual gears using the 3.0 final ratio exactly the same as what they were with the baseline?

So, yeah, there is 3 times greater effect for the rwd RX-7 than the 4wd Evo II (0.015 vs 0.005 quicker). 0.015s is still a small increase in the grand scheme of things, though.

But as RJ showed, you can get a LOT more than just 0.005 or 0.015 improvement, and it's nothing to do with the drivetrain, there are some other differences. I'll have to fire up the PS2 and get running with some test cars but I'll show the results of what I've got going and you can check them for yourself.

But then things got strange. The above tests were done without the Carbon Driveshaft installed (I was thinking that a heavier driveshaft would maximise the effect of the "tranny trick" in reducing drivetrain inertia). So then I repeated the tests with the Carbon Driveshaft
without tranny trick (ie 3.8 fd ratio): 10.687
with tranny trick (ie 3.0 fd ratio): 10.661

0.026s difference. So the lighter Carbon Driveshaft actually increases the effect of the tranny trick. Why???

Nothing to do with the tranny trick actually. It's all to do with removing the extra inertia on the drivetrain that's caused by the heavier standard driveshaft. Check the stock gearbox with a fully customised driveline (triple clutch, racing flywheel & carbon driveshaft), then remove the CF driveshaft and re-test, you will find that the CF driveshaft is the reason you have a lower time.

Hope this all helps and I'll get back to you all with some results from my tests, I'll show one of each drivetrain. 👍

 

[nomis3613]

That's a big difference. You need to test different individual gearsets with the same final ratio. That's why I mentioned my method of reverting back to the stock final ratio after I tune my gearbox.

By "final ratio" do you mean FD ratio or the overall ratio of the gears? I thought what we were discussing here was for say an overall ratio at the wheels of 5:1, whether you should use
5 for the gear and 1 for the FD or
2.5 for the gear and 2 for the FD?

Were the individual gears using the 3.0 final ratio exactly the same as what they were with the baseline?

Yep.

But as RJ showed, you can get a LOT more than just 0.005 or 0.015 improvement, and it's nothing to do with the drivetrain, there are some other differences. I'll have to fire up the PS2 and get running with some test cars but I'll show the results of what I've got going and you can check them for yourself.

Cool, looking forward to it!

Nothing to do with the tranny trick actually. It's all to do with removing the extra inertia on the drivetrain that's caused by the heavier standard driveshaft. Check the stock gearbox with a fully customised driveline (triple clutch, racing flywheel & carbon driveshaft), then remove the CF driveshaft and re-test, you will find that the CF driveshaft is the reason you have a lower time.

Ah...confused...
<re-reads entire thread>
I see you define "tranny trick" as the ability to set gear ratios closer than would be possible without using the Auto Setting. Actually what I was testing was the drivetrain inertia thing. Agreed, a CF driveshaft is lighter, this will improve acceleration. However, a heavier (non CF) driveshaft should show greater difference between running high gear ratios, compared with running a high diff ratio (if the overall gearing is the same- from now on when I say "higher individual gear ratios" I also mean that the FD ratio has been adjusted to give the same ratio at the wheels). This is because the inertia is higher for higher drivetrain revs, and using higher individual gear ratios reduces driveshaft speed. But then my test found that the CF driveshaft actually increases the improvement of higher gear ratios. Then rotary_junkie's tests found the exact opposite. Much confusions...

Hope this all helps and I'll get back to you all with some results from my tests, I'll show one of each drivetrain. 👍

Thanks! That would be great!