FITT Problem Solving - 4wd LSD & Torque Split

[Motor City Hami]

I must admit that with all of my work on LSDs, I do not think that I have cracked the four wheel drive LSD and Torque Split settings. The 4wd drive train just isn't my favorite, so I have spent less time trying to tune these. I just looked through my garage and I haven't driven a 4wd vehicle since before the 2.09 update. During 2.08, I did alot of rally car dirt testing for my FITT Rally vs. Street Tuner Challenge, but I am still torn between a couple of methods for tarmac LSD settings.

I thought that I would come to the community to gather thoughts and to share knowledge to those in the community who are interested in the subject. I have tried 4wd tunes from many of the garages, but I can't get a good feeling for difference in method and difference in lap times. Feel free to add your thoeries and to discuss. Below is more about how I have approached 4wd, but I am not completely happy with the results.

 

[Motor City Hami]

Dirt 4wd tuning:

Again, I have not driven a rally car since 2.08, but during that testing, I found that 50/50 torque split gave the most drive from mid corner off. It also added stability on entry, which was good for some cars, but bad for others.

As for LSD settings, it's hard on dirt to see which tire needs the help because it is nearly impossible to turn any of the tires red. Dirt/Snow is alot of trial and error. Where I ended up was with higher front settings than rear and rear settings that look very close to tarmac rear wheel drive settings.

Subaru Impreza WRC
Front LSD 15/35/7
Rear LSD 10/12/14
Torque Split 50/50

Ford Focus WRC
Front LSD 15/10/5
Rear LSD 10/20/10
Torque Split 40/60

Mitsubishi Lancer Evo Rally Car '97
Front LSD 12/32/5
Rear LSD 12/12/9
Torque Split 50/50

Mitsubishi CZ-3 Rally Car
Front LSD 12/32/5
Rear LSD 12/12/9
Torque Split 50/50

Tarmac 4wd tuning:

I am kind of all over the board on tarmac settings. Low front settins seem to allow the car to rotate more, but it is about the same speed as higher front settings with more rear torque split. Which means that I haven't found the sweet spot yet. It is also difficult to see wheel spin, so a bit of trial and error without much evidence to use as a guide.

Subaru Impreza WRX STi '07 (my hands down best 4wd tune so far - ask Ronald)
Front LSD 10/12/7
Rear LSD 8/10/5
Torque Split 50/50

Mitsubishi Lanser Evo '96
Front LSD 15/35/7
Rear LSD 10/12/5
Torque Split 50/50
Or AYC at 50 vs. using the LSD

Mitsubishi CA-3 Tarmac '01
Front LSD 15/35/7
Rear LSD 10/12/5
Torque Split 50/50
or AYC at 35 vs. using the LSD

Nissan GT-R Black Edition
Front LSD 8/8/6
Rear LSD 8/21/10
Torque Split 30/70
These settings really take away front LSD affect and make the car more Rwd like.

GT-R '07
Front LSD 7/10/5
Rear LSD 7/12/5
Torque Split 35/65

Audi R8 Quattro
Front LSD 12/35/7
Rear LSD 10/12/8
Torque Split 35/65

Lamborghini Murcielago LP Super V
Front LSD 15/32/10
Rear LSD 10/10/7
Torque Split 35/65

Lamborghini Gallardo LP
Front LSD 5/10/7
Rear LSD 7/15/10
Torque Split 25/75

 

[thewheelman83]

This is great LSD setup, Hami. 👍 👍 to you, mate.

 

[XDesperado67]

Just my own opinion here but I think 4wd cars have to be driven a bit differently than FR or MR cars to get the most out of them. Stuff them into corners a bit harder than you would normally with other cars, then get back on the gas a bit earlier and let the front help pull you through the corner. To make that work I almost always go with a 50/50 torque split as lower front doesn't seem to be as effective in grabbing hold and dragging the car out of the turns.
I know a lot of others prefer to run the torque split heavily in favor of the rear wheels and drive them like a FR.

 

[Onboy123]

Just my own opinion here but I think 4wd cars have to be driven a bit differently than FR or MR cars to get the most out of them. Stuff them into corners a bit harder than you would normally with other cars, then get back on the gas a bit earlier and let the front help pull you through the corner. To make that work I almost always go with a 50/50 torque split as lower front doesn't seem to be as effective in grabbing hold and dragging the car out of the turns.
I know a lot of others prefer to run the torque split heavily in favor of the rear wheels and drive them like a FR.

I had a period where, following in RJ's footsteps when he tuned my CT230R, I did the same. Memorable examples were the bonkers Beetle RSi and an Audi A3, both with 45/55 on the power split. Only difference was where RJ got the fantastically mad lift off oversteer by removing almost all the rear downforce on the HKS, to get similar results I had to run almost stupidly soft rear springs, so when it came to quick direction changes, it was never really responsive.

Nowadays, I hardly touch 4WDs since managing 1 diff is already overcooking my brain, but in general, I run 5/20-60 (yes, let's hear it MCH)/5 on the front and 10/20-30/5-10 on the rear.

 

[Motor City Hami]

I tried a few of Roj's Subarus and noticed settings like Front 12/60/10 and rear 10/40/10. They were pretty good, but I cutting the LSD accel and they felt almost the same.

Still trying to fully figure this out.

 

[Onboy123]

I tried a few of Roj's Subarus and noticed settings like Front 12/60/10 and rear 10/40/10. They were pretty good, but I cutting the LSD accel and they felt almost the same.

Still trying to fully figure this out.

Hmm…maybe Accel can be used in excess without having a large effect on the handling and feel? I've ran 40-60 accel on my Imprezas and the only real difference I felt was that the front seemed to turn in quicker, but there also seems to be less "feel".

 

[Johnnypenso]

I have not tuned or driven a lot of 4wd cars from the beginning of the game so I'm curious to see what ideas you guys come up with. My standard approach has always been a 30/70 torque split and LSD's of Low/Higher/Low like 5/20/5, front and back but I've never tried to super tune anything, just for running in open lobbies, back when you could still find decent racing rooms.

 

[Ridox2JZGTE]

MCH, give my Hosaka R33 GTR LSD settings a go It's linked on my sig, Mat123 ( from GTP Hot Version Touge ) liked similar LSD setting on his NISMO R34 GTR Ztune replica.

Basically emulating real life NISMO GT PRO LSD, with low initial torque 6-8kgm, 55 deg cam on accel and 45 deg cam decel for 2 way at the rear, and 55 deg cam on accel + 5 deg cam on decel for 1.5 way at the front.

I have been running LSD like these on most 4WD cars I have :

Front : 6-12/24-30-37/5-12
Rear : 6-12/24-30-37/24-30

Toe : Front +0.04 to 0.35 and Rear +0.16 go down to 0.00 to -0.35
Some cars can have both +toe, +F/-R or +F, 0.00R

The more power the car has, the lower the initial, the higher accel + decel.
The less power, higher initial, lower accel + decel.

Torque split usually 30/70 to 60/40, some cars do have 55/45 ( depends on the tires, power level and balance )

These settings works well with my driving style and no ABS, but might not do well for others as shown at my FITT Nordschleife 2.0 550PP entry

 

[VTiRoj]

I tried a few of Roj's Subarus and noticed settings like Front 12/60/10 and rear 10/40/10. They were pretty good, but I cutting the LSD accel and they felt almost the same.

Still trying to fully figure this out.

Hmm…maybe Accel can be used in excess without having a large effect on the handling and feel? I've ran 40-60 accel on my Imprezas and the only real difference I felt was that the front seemed to turn in quicker, but there also seems to be less "feel".

I do go overboard with my front LSD's on my Subarus. For normal racing, you can lower them without any major change in behaviour. Thing is, I like my Subarus to have idiot-proof powersliding abilities, so that sharper turn-in helps achieve that. 👍

Normally I leave customisable LSD and torque split off my 4WD cars, or rather the ones with trick systems like Nissans with the ATTESA system, or Mitsubishi's AYC system. GT5 simulates all these different electronic 4WD systems that really help the car turn, so replacing it with a mechanical system will usually make the car handle worse unless you know what you're doing with the setup.

This is especially true with the Skylines, where the stock LSD gives you handling feel of an FR car until you screw up and need the front wheels to pull you out of a jam. The customisable LSD just gives it plain ol' 4WD so you don't get that FR-until-you-mess-up feeling anymore.

 

[dlaurence01]

Regarding tuning AWD cars, it is important to consider the design of the chassis. In the case of the R32-R34 Skyline, the car is essentially a RWD car except when the computer sees a massive torque spike that threatens to destabilise the car. As such, it will react better to a higher rear torque split, and the front differential will have relatively little effect on the handling characteristics of the car since a low percentage of the power is going through it.

Conversely, a FWD based chassis such as that of the Evo or Impreza will not benefit from such a large rear torque split. They also are more sensetive to front differential settings, since they handle a higher percentage of the power. In a Sport Compact Car test of the Bozz Speed Evo (I think it was an Evo V), it was found that the car acted almost like a drift car, the result (partly) of having a very strong rear limited slip combined with an almost open front limited slip.

I can't recall precisely which book I read this in (may have been Carrol Smith's Going Faster), but it was suggested that AWD cars be treated more like FWD cars due to the suspension layout and weight balance, and with the exception of FR or MR based chassis I've had good results tuning this way, both in terms of drivetrain and suspension setup. I don't have any settings to share at the moment, but if anyone is interested I can post an example or two.

 

[skyline1683]

Over the last few weeks me and a friend have been fine tuning the R35 gt-r tc and found it not just the LSD and torque spit it's the camber / tow/ and brake balance that have a major effect on the turn in and stability I've left my LSD standard with a 15/85 torque split and adjusted suspension settings slightly and have ended up with a car that's stable under braking turns in beautifully pulls out the corners like a beast
So far it's unbeaten in online races

 

[dlaurence01]

Although yes, a car's suspension setup has more of an effect on the car's behavior, this thread is specifically regarding limited slip and torque split settings, so that is what I was responding to. However, don't underestimate the ability of tuning limited slips and torque split to adjust a car's balance, especially once the suspension is dialed in.

 

[praiano63]

A FR car LSD is relatively easy to set. There are only few parameters to take care for the car have a good answer to yours driving inputs.

For a 4WD car you'll have 2 LSD that have to work together more the torque split diferential that will define the level of your front and rear acceleration LSD settings.

Most of the 4WD don't like to turn, no rotation or just a few, showing under-steer in and out corner. Of course there is some exceptions.

1°)First you need to feel the car you want to tune, with stock settings.
90% of the time for a 4WD, it seems you're driving a timber with 4 wheels.

2°) To give more pivot and more evolution set FRONT AND REAR LSD , INITIAL & DECELL to minimum value front 5/40/5 rear 5/40/5
Then go on track to check the result.

3°)*If your car when under strong braking in a corner loose the rear too much, then increase the REAR DECELL LSD till ok. Not too much because this induced over-steer is good at a certain level depending of your driving style.

*If your car show under-steer out corner then you have to set both front and rear LSD ACCEL. Do like this.
Take a medium speed corner out and check the collor of yours tires under strong accel , from mid to out corner.

Both exterior front & rear tires must be LIGHT BLUE and inside tires DARKER BLUE. This means that this tires will transfer more traction (friction, heat) to the ground out of the circle and this will help to turn ,giving more eagerness to your driving line.

When you have well balanced LSD ACCEL setting by the color of the tires, then increase a bit the rear value . This will give more agressivity to your setting. The amount is up to you. The objective is to grow above the neutral value to be able to induce some oversteer. (Better than waiting passively to come back on the fast line,loosing speed.)

For the torque split, it's up to you depending of the car. Stock is generally good, more rear split can be ok for some lazy cars.
More front split is ok too , specailly on slower turny roads with a better acceleration out corner performance.

This is just my point of view , my personnal way to do when i tune one of this car.

Some good examples:
TOYOTA CELICA 2000GT-FOUR (ST165) '86
NISSAN GT-R SPECV (GT ACADEMY SPECIAL)
SUBARU IMPREZA SUPER TOURING CAR
AUDI LE MANS QUATTRO
NISSAN GT-R R35 Touring Car

><(((((°>°°°°°°°​

 

[DigitalBaka]

For rear drive cars I think my LSD tuning is in a good place but I too have never quite gotten a 4WD car to handle the way I like save for my rally car, which Cy seems to worship. I gave my Impreza an open front but that didn't seem to work as well as it could have. Essentially it ended up as FR with FF understeer. I do like to keep the torque split fairly even though. I think the most off I've gone is 35/65 on a Murcielago SV but everything else has been from 50/50 to 40/60.

I am going to give Praiano's methodology a try the next time I tune one of my beloved Audis and see what happens.

 

[dlaurence01]

*If your car show under-steer out corner then you have to set both front and rear LSD ACCEL. Do like this.
Take a medium speed corner out and check the collor of yours tires under strong accel , from mid to out corner.

Both exterior front & rear tires must be LIGHT BLUE and inside tires DARKER BLUE. This means that this tires will transfer more traction (friction, heat) to the ground out of the circle and this will help to turn ,giving more eagerness to your driving line.

When you have well balanced LSD ACCEL setting by the color of the tires, then increase a bit the rear value . This will give more agressivity to your setting. The amount is up to you. The objective is to grow above the neutral value to be able to induce some oversteer. (Better than waiting passively to come back on the fast line,loosing speed.)

A word of warning; the difference between dark blue and light blue is the temperature of the tires, and does not indicate how well suspension or drivetrain settings are working. This change of color simply indicates that the outside tires are being worked harder than the inside tires and are at a higher temperature. This occurs with any car regardless of drivetrain layout as the weight of the car transfers to the outside tires during cornering.

In order to judge the effectiveness of tuning changes, it is important to let the tires warm up to their full operating temperature, i.e., light blue, because warm tires have better grip and therefore change the handling characteristics of the car. This is especially true for racing slicks, which, in the real world, have very little grip until warm. This is why tire warmers are using when a car is in the pit prior to going on the track, and also why drivers are seen weaving back and forth on parade laps and when the pace car is out.

With regards to the effect of the front differential on handling, it's job, on acceleration, is to essentially drag the front end around the corner. In FWD cars, the front limited slip combined with toe out in the front is used to pull the nose of the car toward the center of the corner, reducing understeer, and the same effect car be used in AWD cars, particularly those based on a FWD chassis.

 

[CyKosis1973]

For rear drive cars I think my LSD tuning is in a good place but I too have never quite gotten a 4WD car to handle the way I like save for my rally car, which Cy seems to worship. I gave my Impreza an open front but that didn't seem to work as well as it could have. Essentially it ended up as FR with FF understeer. I do like to keep the torque split fairly even though. I think the most off I've gone is 35/65 on a Murcielago SV but everything else has been from 50/50 to 40/60.

I am going to give Praiano's methodology a try the next time I tune one of my beloved Audis and see what happens.

Both your Celicas and MCH's Scoobies are excellent examples of 4WD cars working very well (you should have thrown your road-going build on a Caldina, I'm telling you!!)...

{Cy}

 

[Onboy123]

Oi, Y NO ONE MENTION MY IMPREZAS?!

Mind you, I either keep the stock diff or only use them in obscure shootouts, so I can't say it's your fault for ignoring it.

 

[praiano63]

A word of warning; the difference between dark blue and light blue is the temperature of the tires, and does not indicate how well suspension or drivetrain settings are working.
"This change of color simply indicates that the outside tires are being worked harder than the inside tires and are at a higher temperature. This occurs with any car regardless of drivetrain layout as the weight of the car transfers to the outside tires during cornering."
In order to judge the effectiveness of tuning changes, it is important to let the tires warm up to their full operating temperature, i.e., light blue, because warm tires have better grip and therefore change the handling characteristics of the car. This is especially true for racing slicks, which, in the real world, have very little grip until warm. This is why tire warmers are using when a car is in the pit prior to going on the track, and also why drivers are seen weaving back and forth on parade laps and when the pace car is out.

With regards to the effect of the front differential on handling, it's job, on acceleration, is to essentially drag the front end around the corner. In FWD cars, the front limited slip combined with toe out in the front is used to pull the nose of the car toward the center of the corner, reducing understeer, and the same effect car be used in AWD cars, particularly those based on a FWD chassis.

Hello , in my explanation i'm talking about "DARKER" not "DARK" of course.
Also , i don't tune with tire wear ON. A well balanced car don't waste tires so much.
If i tune a car for an Endurance race , of course at this moment , tire wear will be on during the tunning session because this will have a great importance too.
When you talk about "This change of color simply indicates that the outside tires are being worked harder than the inside tires and are at a higher temperature. This occurs with any car regardless of drivetrain layout as the weight of the car transfers to the outside tires during cornering. , you're right . But i'm speaking from " from mid to out corner". At this moment, weight transfer influence on the tires let a bigger place to acceleration and power transmission to the ground.
This LSD fine tune come after the suspension setting. Suspension have a major influence at this moment.
You must be right for FF cars in the real life. But in the game ,they don't drag anything and extreme settings are generally needed to compense the huge understeer.
What is working in the game are FR and MR cars and the fact that acceleration of this cars induce oversteer.
That's why 4WD in the game must be tuned in my opinion with a fully open front LSD, with only a higher front LSD accel setting.

I would love if PD one day let the physics of the game identic to real life. Unfortunately,i think we will have to wait GT6.

Have a good day.

><(((((°>°°°°°°°°°°