Limited Slip Differential (LSD) theory

[OdeFinn]

I have come some conclusion of how GT6 handles LSD values what we enter on settings, and through some start testings those values are indicating directly to locking percentages.
Theory how those values are used is here:

Initial = constant lock amount(preload), affecting during coasting, between Accel and Decel happens often during long turns also, you just coast keeping gas on position what doesn't increase or decrease speed, braking side and acceleration side values easily affecting simultaneously

Acceleration = amount what it will lock more above initial during acceleration, initial+acceleration= total locking

Braking = amount what it locks when there is reducing speed on tires, turning means reducing speed on inner tire, braking(engine and brakes) means reducing both tires speed, both cases are activating this, amount is initial+braking= total locking


And quest extends to gather information on:

Clutch types, how they affect on LSD locking. Fact, it's changing behavior, but where and why and how.
Different propeller axles, how they affect on LSD locking. Fact, it's changing behavior, but where and why and how.
Is difference of initial and acceleration/declaration used for counting locking speed, so can be 60/60/60 lock quicker to 100 than 60/40/40, both are locking 100 during accel and decel, that's for sure, but can there be difference on speed how quickly lock ramps from 60 to 100, or are we hunting placebo.

 

[OdeFinn]

Claims:

1) LSD values are all representing percentages. I.e. 10/3010 is "40/20%" lock with 10% preload.

2) Standard clutch slips slightly and due slipping LSD don't get stiff resistance and won't lock so stiff as it will on better clutches. Difference of locking between clutches, twin plate locks all areas about 0.75%(one click is percent, it can be written as 0.75 clicks) more triple somewhere near 1% more than standard. I.e. Standard clutch on 15/25/25 lock would be acting close to same with dual clutch on 14/24/24, difference is still locking effect speed, with dual and triple clutch lock will engage much faster and that makes car handling slightly different.

3) Carbon Propeller Shaft, makes lock reactions quicker. Less inertia between engine and LSD and reactions are faster. For show easy lock stay on standard clutch and propeller, standard clutch+ carbon propeller is nice combination, smooth lock with quicker response.

4) Clutch type effects your top speed and gear change speed, difference between standard and twin plate is few kmh, twin and triple speed difference is not so big, but overall car handling with rapid gear changes and locking on LSD can make big difference. Standard clutch slips all the time slightly.

 

[OdeFinn]

Place holder

 

[CSLACR]

Question: If 60/40 equals 100, and 120 isn't possible, does this theory suggest that driving with 60/40/40 would feel the same, and produce the same results as driving with 60/60/60?

 

[OdeFinn]

@CSLACR exactly that. Values above 40 on that example are meaningless.

 

[CSLACR]

@CSLACR exactly that. Values above 40 on that example are meaningless.

Ok, thanks.
After my current testing obligation is fulfilled, I'll grab some of the cars and go nuts with them, and see what I find. I already have plans to test a couple things then, so this will fit in nicely.

 

[Bowtie-muscle]

I stated that I would no longer post in the other thread, is it ok with you if I post here?
I have my thoughts on LSD and what happens if you set anything other than a NASCAR on an oval that high initial/accel. But I will leave that alone or post my garage. I applaud what you are trying to do and will be watching. If I do testing I will be sure to show my results.
Good luck with this! Perhaps you may change my opinion. Keep in mind though, I use a DS3, wheel users have commented that they needed to run higher accel for their style and because they use a wheel. Not 100% sure it matters, but it might.

Edit...sorry, auto incorrect phone.

 

[CSLACR]

As a former DS3 user, who ran roughly identical laps to what I run with the wheel, I personally believe 100% that it does not matter. I can still turn a decently mean lap with my rusty thumbs, and quite frankly, I don't believe the hype.
I've never felt I "needed" to adjust a tune because of my input device. *I am sure for some purposes, small changes could be beneficial though.

Just my 2c on that.

 

[killerjimbag]

Well I'm going to fire up GT6, I will test a few NASCAR's with 60/40/40.
One car that I think we should try,Ford Falcon, Aussie one.
I have a very good Nordshliefe tune for that,I'll try that to.

 

[xande1959]

Well I'm going to fire up GT6, I will test a few NASCAR's with 60/40/40.
One car that I think we should try,Ford Falcon, Aussie one.
I have a very good Nordshliefe tune for that,I'll try that to.

these numbers are absurd .60.40.40. if a race is real tire expenditure. or in other tracks (fast and very fast) at most you would 6 laps laps. has to dose acceleration.

 

[CSLACR]

@CSLACR exactly that. Values above 40 on that example are meaningless.

Is 50/50/50 the same as well?

these numbers are absurd .60.40.40. if a race is real tire expenditure. or in other tracks (fast and very fast) at most you would 6 laps laps. has to dose acceleration.

Your English is rough my friend, I'm afraid nobody will be able to understand this post. I know I don't.

Are you translating on Google?

 

[TurnLeft]

Good idea to transfer this to it`s own thread 👍, I have a few things to settle on other threads (tests/reviews/tuning) and then I`ll be able to start on this. Before I start I will run my ideas by so we can see if they are viable and to make sure there are no loop holes. see you soon .

 

[DaBomm4]

Small question, just showing my lack of knowledge, in the case of a completely locked LSD while going around a corner, shouldn't the inner wheel be the wheel sliding first on the surface rather than the outer wheel? Or is it, since the outer wheel is not moving fast enough to go around the corner efficiently, it is dragging and then sliding first? This is how I understand what is going on and I would like to improve that knowledge.

Edit: Question based off of what I am seeing while driving on GT6.

 

[CSLACR]

yeah, backwards

 

[coryclifford]

The inside wheel turns faster naturally.

Outside wheel has the greater path and turns faster.

 

[CSLACR]

Yeah, backwards. Derp.

 

[xande1959]

Your English is rough my friend, I'm afraid nobody will be able to understand this post. I know I don't.

Are you translating on Google?

yes google translator

 

[CSLACR]

yes google translator

Are you saying it would ruin the tires?

Google translator is so bad.
I don't know of better though

 

[OdeFinn]

Is 50/50/50 the same as well?

100% lock during Accel and Decel, but when coasting 50% lock, values above 50 on Accel or Decel are not making any difference in this example.

in the case of a completely locked LSD while going around a corner, shouldn't the inner wheel be the wheel sliding first on the surface rather than the outer wheel?

Depends traction, used torque etc.
So no direct answer available
Outer tire have to travel longer distance, if traction is there then inner slips on forward, if traction is on inner wheel then outer slips "backwards" by running slower than moving.

@xande1959 yes numbers are absurd for racing usage, but easiest numbers to use on theory testing purpose.

 

[xande1959]

Are you saying it would ruin the tires

yes. A a race event has fast tire wear or very fast. I do not use those numbers LSD.

 

[DaBomm4]

Ok, situation in game, 60/60/60 LSD on a RWD car, accelerating out of a corner and the outer tire starts to turn red first, thus loosing traction. I have only two explanations for this, either the outer tire is spinning faster than the inner tire for the available traction, or the outer tire is dragging. If I understand a locked LSD, should it not be the inner tire spinning first?

I am not trying to be complicated, just expressing my confusion.

 

[coryclifford]

I'll just throw my two cents out there cause why not?

I listen to the tires. If the inside peels, I add a digit or two to both initial and accel. If the outside peels, I decrease it. Most of my numbers are about 10 to 15.

Deceleration is pretty car dependent.

I like the theories, but the actual use is what really matters.

 

[OdeFinn]

@DaBomm4 on your case answer lies on suspension setup, not because LSD. Only part of LSD is that if you just changed throttle position from coasting to Accel and LSD kicks traction out.

 

[coryclifford]

If I understand a locked LSD, should it not be the inner tire spinning first?

You're correct. We have to default back to, this is a game.

 

[CSLACR]

Ok, situation in game, 60/60/60 LSD on a RWD car, accelerating out of a corner and the outer tire starts to turn red first, thus loosing traction. I have only two explanations for this, either the outer tire is spinning faster than the inner tire for the available traction, or the outer tire is dragging. If I understand a locked LSD, should it not be the inner tire spinning first?
I am not trying to be complicated, just expressing my confusion.

If you are exiting a corner(wheel turned) the inside wheel burns up and turns red with a low(loose) LSD, and the outside goes first if it is high.(tight/locked)
Locked LSD's spin at the same time.

@DaBomm4 on your case answer lies on suspension setup, not because LSD. Only part of LSD is that if you just changed throttle position from coasting to Accel and LSD kicks traction out.

No, the LSD accel directly changes which tire slips / turns red first. (under power, while still turning)

You're correct. We have to default back to, this is a game.

Locked LSD spins at the same time.

 

[DaBomm4]

Locked LSD's spin at the same time.

Just trying to clarify, since they spin at the same time/speed, should it not be the tire with the shortest distance to be the one to spin first?

 

[CSLACR]

Just trying to clarify, since they spin at the same time/speed, should it not be the tire with the shortest distance to be the one to spin first?

Cars with open diffs burn the inside tire up, cars with locked diffs spin the outside wheel and slide. Yes, maybe to an extent the inside should spin first, but it's not really when the inside spins that you worry, it's when the outside does.

The inside spins first either way, it's just a question of how quickly the outside follows.

Edit: The inside doesn't have weight on it, so it takes more wheelspin to get hot and turn red, depending how long it takes to break the outside wheel(hot tight or high the lsd is) either can turn red first.
5 - inside / 60 - outside

 

[DaBomm4]

Cars with open diffs burn the inside tire up, cars with locked diffs spin the outside wheel and slide. Yes, maybe to an extent the inside should spin first, but it's not really when the inside spins that you worry, it's when the outside does.

The inside spins first either way, it's just a question of how quickly the outside follows.

Ok, so essentially what I am seeing is the outside follows faster than the time it takes for the inside to start heating up, correct? If so, I think I understand better now.

 

[OdeFinn]

@CSLACR @DaBomm4 inside burns first on open diff if weight is transferred to outer tire, same on locked. There is no simple answer on question what is not giving all current aspects of weight transfer, tire grip, used torque etc.
This when we're speaking 100% full lock, LIMITED slip differential which is not 100% is totally different thing.

 

[Bowtie-muscle]

@DolHaus needs to be part of this discussion. He mentioned once, don't remember where, that setting initial to 15, accel to 10, decel to 10 was the same as setting to 15/15/15. Because the initial overrides the others. Something to that effect. I tested it once and it seemed to hold true. Since, I have always had initial lower or equal to accel, never higher. But, for me, decel was not affected as much.

Just my 2 cents.