LSD- How to set it properly?

[nMd_pRo]

Hi guys, this is my first post, although i've been seeing GTP a while,

Back to the topic,

i've seen many threads where peple talk about this but i don't belive they help you set the LSD that good, so i would like you to help me setting mine.

I know what the LSD does in theory but i don't really know what to do,

So if you could tell me the answer to these few questions i would be very apreciated.

What does the incial torque when i set it high and what does it do when set low? does it influence anything else?

when i set my accel in front high what does it make understeer or oversteer?
Same answer for the rear accel.

So if you could tell me this it would be a very grateful help.

Regards.


PS: Sorry for my bad english but i actually live in Portugal.

 

[daveyules]

Initial Torque should be named something else because it doesn't clearly explain what it does. When you increase initial torque, you're increasing both accel and decel sensitivity equally. Increasing it will encourage your car to understeer on both throttle-on and throttle-off.

Increasing the locking force of an LSD on accel or decel encourages understeer. The benefit of increasing locking force is that you can stop one wheel from spinning wildly without providing acceleration; increasing locking force will transmit power more equally between the drive wheels on a specific axle.

Keep your eye on your tire display when driving and in replays. If the inside tire turns red while accelerating out of a corner then you know your locking strength is not high enough. If the outside tire turns red, it's too strong. Find the middle ground.

Cheers

 

[Highlandor]

Initial Torque should be named something else because it doesn't clearly explain what it does. When you increase initial torque, you're increasing both accel and decel sensitivity equally. Increasing it will encourage your car to understeer on both throttle-on and throttle-off.

What should I be adjusting on the LSD if my car (R34 gtr) is not turning in very well at all.

I've tried adjusting the rear brakes to be higher than the front but it hasn't seemed to have a major effect.

It's been fully tuned, running sports soft tyres and 600bhp, my R35's (V spec, GTR, Proto and TMS) don't have this problem, the R34's I got from the used dealer doesn't have this problem either but the R34 premium from the new dealer just doesn't seem to want to turn in at all, it's got me baffled.

Which part of the LSD can I adjust and in what way to help with this. At the moment I'm running without a diff as when I put a diff on it seems to make the car understeer even more on turn in, I've tried adjusting it both ways but it doesn't seem to have an effect, whereas I remember on GT4 it did, plus adding a LSD to my other cars hasn't affected them in this way, I'm a bit confused.

Any ideas / advice / thoughts???

Many thanks for any advice or help you could give.
H

 

[itstheDRE4M]

Initial Torque Settings
Opening (lower values) Improves the cars manoeuvrability. Reduces the effect of the accel. and decel. LSD settings.
Locking (higher values) Increase the effect of the accel and decel LSD settings up to a point, after which the effect will decrease. Reduces the cars manouverability.

Accel. Settings
Locking (higher value) Increases traction out of corners by limiting wheel spin. Limits the car’s ability to turn, particularly in tight corners.
Opening (lower value) Reduces traction out of corners by increasing the chances of wheel spin. Improves the car’s ability to turn, particularly in tight corners.

Decel Settings
Locking (higher value) Increases stability when decelerating into a corner. Limits the car’s ability to turn.
Opening (lower value) Reduces stability when decelerating into a corner. Improves the car’s ability to turn.

LSD's aren't always the best decision for every car. Skylines are included in this.

 

[oppositelock]

Front engine AWD cars typically require low initial and decel settings. This is my typical baseline setup, try it and see if it helps any.

F Inital: 6
F Accel: 18
F Decel: 6

R Inital: 6
R Accel: 36
R Decel: 12

Reinstalling the stock diffs sometimes works also.

 

[GT5SER]

Do a search!

https://www.gtplanet.net/forum/showthread.php?t=166129

- Jeramy

 

[daveyules]

When equipping an LSD, make sure to set it to all 5s at first. You are correct that installing it causes more understeer, because the LSD you can purchase has stronger default settings than the stock LSD.

After you set everything to 5s, start increasing rear accel until you've found your favorite setting. If the car rotates too much when braking increase the rear decel to your liking.

 

[nMd_pRo]

I'll try to do it like you told me to, but i belive that my understeer problem is related to my torque distribuition, i'm acually using 10/90, but i think i will now figure out some nice LSD setting, although i belive that my Audi is a problem trough corners

 

[87lc2]

Keep your eye on your tire display when driving and in replays. If the inside tire turns red while accelerating out of a corner then you know your locking strength is not high enough. If the outside tire turns red, it's too strong. Find the middle ground.

Cheers

This is the best info I have seen yet for setting up the LSD properly. I was getting wheelspin exiting corners in some of my big hp street cars and always just kept raising accel because most people on this forum will tell you thats what will stop it. However, that is not the case at all. Like daveyules said, if the outside tire is spinning, lower it. Worked like a charm for me. I went from a 36 accel value to a 12 in my 608 hp GNX and now have no wheelspin whatsoever on exit. I really wish I would have seen this sooner.

 

[tgrey]

Awesome thread, thanks guys. Subscribed.

 

[BlueSky]

Initial Torque should be named something else because it doesn't clearly explain what it does. When you increase initial torque, you're increasing both accel and decel sensitivity equally. Increasing it will encourage your car to understeer on both throttle-on and throttle-off.

Increasing the locking force of an LSD on accel or decel encourages understeer. The benefit of increasing locking force is that you can stop one wheel from spinning wildly without providing acceleration; increasing locking force will transmit power more equally between the drive wheels on a specific axle.

Keep your eye on your tire display when driving and in replays. If the inside tire turns red while accelerating out of a corner then you know your locking strength is not high enough. If the outside tire turns red, it's too strong. Find the middle ground.

Cheers

Great explanation. Thanks for the post!

 

[PhillGuy]

Sorry but I still don't understand what exactly each of the setting is doing. I think I get the handling results but I don't understand on a technical level what these numbers mean.

 

[SS_1182]

Initial Torque should be named something else because it doesn't clearly explain what it does. When you increase initial torque, you're increasing both accel and decel sensitivity equally.
Cheers

I disagree with this statement. The higher the initial torque value, the more torque it takes for the LSD to lock up. The lower the value, the less amount of torque is required to lock the differential. 5/60/60 locks faster than 60/60/60.

 

[87lc2]

Sorry but I still don't understand what exactly each of the setting is doing. I think I get the handling results but I don't understand on a technical level what these numbers mean.

The higher the number, the further locked the differential gets.

60 = full lock (both wheels get equal power all of the time)

0 - full open (whichever wheel has less resistance gets the power)

As far as the game goes, its much more important to understand what the effects are than how it actually works. I was the opposite, I know how a locking differential works but was having trouble understanding how the game applied it.

 

[SS_1182]

The higher the number, the further locked the differential gets.

60 = full lock (both wheels get equal power all of the time)

0 - full open (whichever wheel has less resistance gets the power)

As far as the game goes, its much more important to understand what the effects are than how it actually works. I was the opposite, I know how a locking differential works but was having trouble understanding how the game applied it.

Again, this is only true for the last two settings, not of the first one.

 

[BlueShift]

I disagree with this statement. The higher the initial torque value, the more torque it takes for the LSD to lock up. The lower the value, the less amount of torque is required to lock the differential. 5/60/60 locks faster than 60/60/60.

I agree on that.

In fact I say the exact opposite of davey.

 

[BlueShift]

The higher the number, the further locked the differential gets.

60 = full lock (both wheels get equal power all of the time)

0 - full open (whichever wheel has less resistance gets the power)

As far as the game goes, its much more important to understand what the effects are than how it actually works. I was the opposite, I know how a locking differential works but was having trouble understanding how the game applied it.

Lock is low initial, open is high initial. The purpose of a LSD is to lock.
Initial is two things : the amount of tire slipping you allow (more slips more) and the speed of your locking (more locks slower). The more initial, the more your LSD is violent : it will lock less fast but with greater effect.

The effect of initial is controled by this formula, as GT4's official guide says :
(50 +- initial / 2) is the moment of locking.

Say your initial is 10.
Your initial setting won't allow more than 45% inside spin / 55% outside spin. After that, it locks.
To check if your car reached 45%/55%, it take times which is lower than to check if it's 25%/75% (initial at 50). And it take a lot more time with heavy transmission parts as budious (re)discovered in his clutching thread, so you can put higher accel values without having it lock too fast (still, this is not good because high LSD makes your outside wheel spin). Heavier parts gives you more engine brakes too, so they are free decel points, all of this at the expense of shifting speed (plate) and accelerating speed (flywheel).

Accel controls inside/outside tires slipping under accel, it's a fixed value that only have a "good" value, no tuning there.
Decel controls the amount of brake engine you give to your wheels (0 mean clutching, 60 is a lot). Since it gives you a lot more braking, high decel tend to understeer because your tires locks.

If you give higher values to decel than to accel, you'll need high intial.
If you give lower value to decel than to accel, you'll need low initial.

Reason is when your accel LSD take the relay from your decel LSD, if accel is set low you can have a violent power afflux (violent lock, high initial).
If if set too sensitive, you'll need low power afflux (smooth lock, low initial).

On any car that isn't a 4RW, setting accel is the easiest.
On a propulsion car :
If the inside tire lock before the outside, increase accel.
If the outside tire lock before the inside, decrease accel.

You can do donuts to check this, if your car is powerfull enough.

On traction, I think it's the opposite.

I disagree with davey because if you loose outside grip (high accel) it mean oversteering and powersliding.

Initial have effect whatsoever on accel and decel setting. It's a myth I still beleived in two weeks ago (Rotary broked it )

For decel, what I do now is rear decel = 60 - rear accel.
For initial, what I do is taking the absolute value of the difference between the accel and decel and apply a modificator.
rear initial = | rear decel - rear accel | + sign(rear decel - rear accel) * min (rear accel/2, rear decel/2)

And that's it, for the rear train.

If it's a 4RW, (edit - it's not that crap formula)

For FR car LSD I need more pratice. Decel effect is inverted for these cars.

I'm posting a perfect-LSD-NSX tonigth or tomorow.

 

[Slurm]

Blueshift, I've gone from thinking that you're very helpful, to thinking that you're very confusing.

 

[BlueShift]

Yep, and I'm editing that last post again.

The 4WR is not that thing, I've got to clear my method in an appropriate thread.

For the NSX the LSD formula is perfect, I've got to check if it's good on other cars too.
I seem to understand tires' effects on LSD now (-2 to accel per tires from R3, +2 to decel, and effect on initial depending if accel or decel is higher than the other)

 

[oppositelock]

Again, this is only true for the last two settings, not of the first one.

We got everybody disagreeing with everybody up in here. Initial torque is not inverted. Nothing is inverted in this game. It's also not some sort of slip threshold for the LSD to start working. It's the amount of lock being applied when the car is at rest or travelling a constant speed. That's it. No six hundred word explanations required.

 

[NMRacing]

You guys all have initial torque backwards.

Initial torque is the straight line locking strength of your diff. When you have bad wheel spin on corner exit it has nothing to do with Initial torque and everything to do with Acceleration sensitivity.

When you go from deceleration to acceleration the LSD engages (locks), regardless of wheel spin.. This is initial torque or preload, Increasing Initial torque increases the force required to disengage (unlock) the diff.

Now because the LSD is under preload does not mean it will stay locked when you get wheel spin. This is because you hit the initial strength first, therefore disengaging (Unlocking) the LSD.

Blueshift is right with acceleration sensitivity. It determins how sensitive the LSD is to wheel spin. Not sensitive enough and the inside wheel will spin more. To sensitive and the outside wheel wont let the inside wheel spin enough.

 

[dennisp83]

I will bookmark this thread and try to read it 5 times a day, maybe on one day I get it and can turn it into practice
Thanx for this topic anyway, I really want to understand the proper use of the LSD

 

[Adrenaline]

For new people, looking for an easy break down...

Acceleration = Corner Exit traction: (On throttle only)
If the inside tire spins, increase accel.
If the outside tire spins, decrease accel.
The 'sweet spot' will vary person to person, but it seems you want the outside tire spin just barely enough to help turn the car through exit.

Deceleration - Corner Entry maneuverability: (While coasting or braking)
The lower this setting, the more the car is allowed to rotate into the corner (open diff)
The higher this setting, the more 'stable' the car will be on entry, but won't turn as sharp. (more locked diff)

Initial . . .
I'm still testing this one. Seems to be the hardest to notice.

 

[87lc2]

We got everybody disagreeing with everybody up in here. Initial torque is not inverted. Nothing is inverted in this game. It's also not some sort of slip threshold for the LSD to start working. It's the amount of lock being applied when the car is at rest or travelling a constant speed. That's it. No six hundred word explanations required.

Exactly, this thread started out very helpful and has turned confusing for people trying to figure out how to set this in the game.

daveyules description was dead on, i have revised a lot of my tunes that, like many others here, had a very high value for accel. Using daveyules inside/outside tire spinning method, most of my accel numbers have went down between 10-20 and I have no wheel spin anymore on corner exit as well as better handling.

 

[BlueShift]

We got everybody disagreeing with everybody up in here. Initial torque is not inverted. Nothing is inverted in this game. It's also not some sort of slip threshold for the LSD to start working. It's the amount of lock being applied when the car is at rest or travelling a constant speed. That's it. No six hundred word explanations required.

Car at rest ??? Constant speed ???

Take a very fast FR or RR understeering car, with high rear aero, like a Speed12, long gearbox, put intial @ 5 and go in the straigth line of LeMans, start from 0km/h after the first chicane.

The last sligth curve before the Hunaudières curve, you won't pass it but you're still accelerating : constant speed ???

Put initial @50, you'll pass it.


So :
What is the most violent 5 or 50 ? I say 50
What do you think is fastest to lock/unlock 5 or 50 ? I say 5

You see that @ 30, you'll lock more times (I'd say 2-3), but less violent, than @ 50 (I'd say1-2).

High initial = more violent but slower (so less frequent), just like I said. And that comes from the offiial initial formula from GT4 I gave :

@50 : the tires slips until 25/75, LSD locks, tires don't slips by going back to 50/50 or something like that then come back to 25/75 and BLAM big lock again.
@30 : the tires slips until 35/65, LSD locks, tires don't slips by going back to 50/50 or something like that then come back (faster) to 35/65 and BLAM lock again.

Since @50 from 50/50 you need to pass by 35/65 to lock @ 25/75, what I say (edit - *about time) is easy to understand.
Since @50 your LSD want you to go back at 50/50 (or something like that), from 25/75 so +25/-25, it's more violent than at 35/65 so +15/-15. : @50 initial a range of 50 will be given to your, @30, a range of 30 will be given to your cars.


Please, may you give me an example I can reproduce where what you tell is true so I can understand your point of vue ?

 

[joshdavis89]

what if i want total lock up like for drifting?

 

[KForceOH]

I posted what I believe to be some pretty good info in another thread in general. I will just dupe it over to here, it was in 3 post so some info might be repeated but here goes
__________


I break the LSD down to 3 positions on track then tune from there.

1 (Inital)) Car spins coming out of corner on acceleration
2 (Accel)) Car spins after corner has been exited and is under hard acceleration
3 (Decel)) Car spins when lifting off gas or braking before corner

Increase each number until the car stops spinning one tire in each of the three position. If you are fine everywhere but when you hit the brakes or lift, then just increase the last number. You want to run the numbers as low as possible without spinning one tire on the car.

I also run some basic LSD tuning based on the HP of the car.

500-below 13/25/7
500-700 18/32/9
700-above 22/35/11
________________________

A locked LSD (higher numbers) will make both wheels spin at the same speed and therefore cause the car to push through the turn.

You want to find that number on your LSD to where it allows the wheel to spin fast enough to turn but not fast enough to unload the wheel and spin out.

Ever driven a 4x4 with a locked front end and tried to steer it around a corner without backing up 50 times? Same concept.

A good test to see....turn LSD inital to 60 and drive, then turn to 5 and drive. You will see exactly what I am saying.

If the diff is open when you spin one tire the other will go the opposite direction in real life, but yea it is essentially just what you said.

If it is locked you are exactly right both will spin at same speed with a 50/50 power split and that is a constant value.

Speed and time in this case would mean the same.

Now this is a LSD we are tuning so it is really never a fully true locked rear but very very close with numbers of 60.

What you want to do is think of it as a clutch, (at least I do), I just control the slip with the LSD numbers.

_________________________________

Break it down to one single corner. You hit the brakes, turn the apex, and accel out. Now think of those 3 parts as the 3 numbers in the LSD.

If you come into the corner and hit the brake and you rear end slides out or the car is unstable then TURN UP DECEL.

In the middle of the corner and partial exit when you hit the gas if your car spins in the rear and gets to loose for you the TURN UP INITAL.

After exiting the corner and your on the gas and the car shifts 2nd - 3rd and spins loosing grip then TURN UP ACCEL.

You can tune the car pretty good and get a good understanding of whats going on by just hitting one corner on a track and keep doing the same one with different numbers you can feel the car and the adjustments.

You want to get the numbers as low as you can and still be able to hammer on the car. A lot has to do with driving style also. If you are light on the pedal you can run lower numbers. If your a lead foot, like me lol, you need higher numbers.

Try running those base numbers I posted earlier based on the HP of your car and go from there.

Anything else just ask I'll try and answer my best

 

[SS_1182]

I posted what I believe to be some pretty good info in another thread in general. I will just dupe it over to here, it was in 3 post so some info might be repeated but here goes
__________


I break the LSD down to 3 positions on track then tune from there.

1 (Inital)) Car spins coming out of corner on acceleration
2 (Accel)) Car spins after corner has been exited and is under hard acceleration
3 (Decel)) Car spins when lifting off gas or braking before corner

Increase each number until the car stops spinning one tire in each of the three position. If you are fine everywhere but when you hit the brakes or lift, then just increase the last number. You want to run the numbers as low as possible without spinning one tire on the car.

I also run some basic LSD tuning based on the HP of the car.

500-below 13/25/7
500-700 18/32/9
700-above 22/35/11
________________________

A locked LSD (higher numbers) will make both wheels spin at the same speed and therefore cause the car to push through the turn.

You want to find that number on your LSD to where it allows the wheel to spin fast enough to turn but not fast enough to unload the wheel and spin out.

Ever driven a 4x4 with a locked front end and tried to steer it around a corner without backing up 50 times? Same concept.

A good test to see....turn LSD inital to 60 and drive, then turn to 5 and drive. You will see exactly what I am saying.

If the diff is open when you spin one tire the other will go the opposite direction in real life, but yea it is essentially just what you said.

If it is locked you are exactly right both will spin at same speed with a 50/50 power split and that is a constant value.

Speed and time in this case would mean the same.

Now this is a LSD we are tuning so it is really never a fully true locked rear but very very close with numbers of 60.

What you want to do is think of it as a clutch, (at least I do), I just control the slip with the LSD numbers.

_________________________________

Break it down to one single corner. You hit the brakes, turn the apex, and accel out. Now think of those 3 parts as the 3 numbers in the LSD.

If you come into the corner and hit the brake and you rear end slides out or the car is unstable then TURN UP DECEL.

In the middle of the corner and partial exit when you hit the gas if your car spins in the rear and gets to loose for you the TURN UP INITAL.

After exiting the corner and your on the gas and the car shifts 2nd - 3rd and spins loosing grip then TURN UP ACCEL.

You can tune the car pretty good and get a good understanding of whats going on by just hitting one corner on a track and keep doing the same one with different numbers you can feel the car and the adjustments.

You want to get the numbers as low as you can and still be able to hammer on the car. A lot has to do with driving style also. If you are light on the pedal you can run lower numbers. If your a lead foot, like me lol, you need higher numbers.

Try running those base numbers I posted earlier based on the HP of your car and go from there.

Anything else just ask I'll try and answer my best

Your initial torque theory is wrong, IMO.

 

[oppositelock]

Car at rest ??? Constant speed ???

Take a very fast FR or RR understeering car, with high rear aero, like a Speed12, long gearbox, put intial @ 5 and go in the straigth line of LeMans, start from 0km/h after the first chicane.

The last sligth curve before the Hunaudières curve, you won't pass it but you're still accelerating : constant speed ???

Put initial @50, you'll pass it.


So :
What is the most violent 5 or 50 ? I say 50
What do you think is fastest to lock/unlock 5 or 50 ? I say 5

You see that @ 30, you'll lock more times (I'd say 2-3), but less violent, than @ 50 (I'd say1-2).

High initial = more violent but slower (so less frequent), just like I said. And that comes from the offiial initial formula from GT4 I gave :

@50 : the tires slips until 25/75, LSD locks, tires don't slips by going back to 50/50 or something like that then come back to 25/75 and BLAM big lock again.
@30 : the tires slips until 35/65, LSD locks, tires don't slips by going back to 50/50 or something like that then come back (faster) to 35/65 and BLAM lock again.

Since @50 from 50/50 you need to pass by 35/65 to lock @ 25/75, what I say (edit - *about time) is easy to understand.
Since @50 your LSD want you to go back at 50/50 (or something like that), from 25/75 so +25/-25, it's more violent than at 35/65 so +15/-15. : @50 initial a range of 50 will be given to your, @30, a range of 30 will be given to your cars.

This isn't intended as a personal insult, and I hope you don't take it as such, but I've read this three times and can still only understand about half of it. Votre anglais est meilleur que mon français, but still, I feel like I'm trying to decrypt Klingon VCR instructions.

Please, may you give me an example I can reproduce where what you tell is true so I can understand your point of vue ?

This I can do.

Initial torque & cam angle

The initial torque (break away torque) is a pre-load torque on a LSD. Up to that torque load, the LSD locks the differential even without any rotational difference between the wheels. The initial torque and the cam angle on the cam rings determine the responsiveness of the LSD on the driver's steering and throttle inputs. The higher the initial torque and the higher the cam angle, the more responsive an LSD becomes. However, too much initial torque makes a vehicle extremely hard to turn and very high cam angle affect the vehicle's smoothness. A good performance LSD achieves an excellent balance of those two important factors.

This is from a company that makes LSDs: http://www.ppi-ats.com/LSD/LSD_basics.html

From what I can grasp, it seems your theory is that the LSD is by default totally open until enough difference in axle speed occurs to causes it to lock. There is actually a type of LSD that works this way, it's known as a viscous LSD, but it's not represented in GT. As we can see from this link, a clutch type LSD like the one in the game is actually fully locked until enough opposing force is transmitted through the axles to cause the clutch plates to slip. The initial torque indicates how firmly the these plates are pressed together when they're installed in the case. A lower number indicates less pressure, meaning less force is required to make them slip. When you either accelerate or decelerate the cam moves either forward or backward and forces the plates even harder together, meaning even more opposing axle force is required to unlock the plates. This is why I said the initial value indicates the amount of lock when static or travelling at constant speed. Their description of high initial torque being "more responsive" seems to conform to your experience of it being "violent".

Some things I'm not so sure of. What does an initial torque value of 5 indicate? Is that a 5% difference in axle force? 5 newton-meters? Is it an arbitrary value? If I had to guess I'd say it's a percentage. Also, are the acceleration and deceleration values added on top of the initial torque or are they totally independent? For instance, if you have an initial value of 10 and an acceleration value of 20, does that add up to a total lock of 30 when you hit the throttle? Or is the total acceleration lock 20 regardless of what the initial value is? Personally I think it's the latter, but I can't prove that.

Just to sum up:

OppositeLock's LSD Theory: PD looked at how a real LSD works and implemented a model that, while somewhat flawed, more or less conforms to reality.

BlueShift's LSD Theory: PD looked at how a real LSD worked, threw the whole concept into the trash, and then created a model out of thin air which works totally opposite of reality for absolutely no reason whatsoever.

 

[NMRacing]

Some things I'm not so sure of. What does an initial torque value of 5 indicate? Is that a 5% difference in axle force? 5 newton-meters? Is it an arbitrary value?

It appears to be torque related. but not engine torque. Cars with wider tires (hence more grip) consistently require less initial to disengage the clutches in the LSD. regardless of the technical measurement being used this is pretty much a personal preference setting. I ran higher and lower values in different cars and could find no real acceleration benefit.

Also, are the acceleration and deceleration values added on top of the initial torque or are they totally independent?

Completely independent. run 5/5/5 and the inside wheel will spin. run 30/5/5 the inside wheel will still spin. run 60/5/5 if you can make it around the corner the inside wheel will still spin.