Limited Slip Differential (LSD) theory

  • Thread starter OdeFinn
  • 170 comments
  • 18,747 views
xande1959
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.
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Actually no 60 60/60 with 0 camber and -25 toe lasts 7 laps vftw.
I tested online by myself,was fine,then went into online room, 60/40/40 will not hold lower line when transferring from top groove to bottom groove in online 16 player room, real grip real tire wear real draft,no boost no aides,seems to want to loose grip, in the rear,went back to 60/60/60 and it was good,it seems going to 40/40 is spinning the tires,there was no suspension changes. I am going to try and get 4 guys to run together,2 up top at 60/60/60 and 2 at 60/40/40 on the bottom and see if they feel any wheel slip.
 
If someone wishes to try it yourself here it is,it will run in pro rooms very well.
No "glitch tune since GT5 lol"
892 HP. No aides no ABS RS tires
RH
90 90
SR
20.25. 20.75
Comp
8. 5
Ext
8. 5
Are
4. 4
Camber
0. 0
Toe
-0.25. -0.25
LSD
60/60/60
BB
5. 8
Aero
200. 400
Trans reset to default.
Final gear 5000
Max speed all the way left
First all way left
Second all way left
Third all way left
Fourth all way right.
Set final to 3.115 to 3.200
Test it works well and I'm sure results will differ huge compared to a flat track.
 
OdeFinn
@killerjimbag not wanting to be picky, but no data to show difference ;)
Can you get that same recorded on data logger?
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Yes I will do some tomorrow, I've driven 50000 miles at Daytona, in a NASCAR, I now changes when I feel them. But yes I will do some tomorrow, I want some draft partners to see if the slipstream is causing an effect and if its limited to which line you drive and aero buffering. I'm wondering if tires are not as stuck do to aero affect at 40/40 (traction loss compared to 60/60),I know it may sound funny,but that seems to be the affect I feel in the car/ wheel. Will do tomorrow, company just dropped by.
 
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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.
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You're over-thinking it. As you familiarize, you'll learn that those details aren't as important as you'd think, not nearly at all in GT6.
 
Sorry guys no testing today,5 months of snow does that to you,did yard work and took the bumpers, hood and trunk of of the Chevelle, sun and a few beers and a wrench,what's better? Uhm getting my 65 perhaps, but that's100 miles away.
 
Also under investigation is:
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.

Plenty of information coming up from these.
 
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I've started to try things out but I'm having a small problem, I want to use Tsukuba as the testing track, last curve before the finish line.

I want every test with all the different values to be done at the same speed, when I lock it to example 2nd gear, once the rpm passes the red line while holding full throttle, the rpm jumps up and down giving me different drive train wheel speeds, I've tried glueing a little piece of plastic to stop the joystick from reaching the end, but that didn't work out properly (it unglued). If you have an idea on how to keep it at a fix speed (please don't say throttle control I'll never be able to do 30 something tests that equally) it would be very helpful so we can get an accurate reading, before anyone gives me their ideas, please test them out to see if they do work. Thanks.
 
OdeFinn
Also under investigation is:
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.

Plenty of information coming up from these.
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If you put a FWD in reverse, park, and turn the wheel, hold the brake and rev the engine, then you release the brake, once you do, wheelspin starts immediately, @ 60/5/5, the inside wheel turns red first. @ 5/60/5, the outside wheel turns red first.

They can't be equal if different wheels turn red under the same conditions, and in both conditions, throttle is already applied, so if I understand this compounding theory correctly, they would represent the same amount of lock, which is not what was displayed to me.
 
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.
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That's very interesting. I don't fully "get" the LSD in GT6. I mean, I understand it... I know what the settings are supposed to do, but I can't adjust my own LSD settings. Actually, I can and I have made adjustments to the Decel parameter of some of my LSDs, but I never adjust Init or Accel on my own. Anyway, I'd like to read more about this theory you've suggested. Yes, I know you said that DolHaus is the person who proposed this theory...

It's strange for me to imagine an LSD that has 60% lock to begin with (the Initial), but then lowers to 30% when you press the gas pedal (Accel) and then lowers to 20% lock when you apply the brakes. I just made up a hypothetical LSD, of course.

Also, I hate not having units with the LSD. We can apply numbers 5 thru 60 to each parameter. Is that 5%? 5 what? Why does it only go to 60? Because if the unit is percent, then we can not have a fully locked LSD?! Why couldn't they just make the parameters adjustable from 1-100? Ugh...It frustrates me so much.
 
CSLACR
If you put a FWD in reverse, park, and turn the wheel, hold the brake and rev the engine, then you release the brake, once you do, wheelspin starts immediately, @ 60/5/5, the inside wheel turns red first. @ 5/60/5, the outside wheel turns red first.

They can't be equal if different wheels turn red under the same conditions, and in both conditions, throttle is already applied, so if I understand this compounding theory correctly, they would represent the same amount of lock, which is not what was displayed to me.
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Sorry, but:
futurama-fry-should-i-lol-or-roflmao.jpg


Thanks for proofing at PD has modeled mechanical LSD.
Test would do something if testing 60/5/5 and 5/5/60
 
OdeFinn
Sorry, but:
View attachment 353387

Thanks for proofing at PD has modeled mechanical LSD.
Test would do something if testing 60/5/5 and 5/5/60
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This confuses me, why would having the brakes maxed make a difference while accelerating? Reverse is still accelerating unless I am mistaken. What @CSLACR tested is if you get the same effect or not from 60/5/5 and 5/60/5, and with your theory, that is what you are looking for, right?
 
ALB123
Also, I hate not having units with the LSD. We can apply numbers 5 thru 60 to each parameter. Is that 5%? 5 what? Why does it only go to 60? Because if the unit is percent, then we can not have a fully locked LSD?! Why couldn't they just make the parameters adjustable from 1-100? Ugh...It frustrates me so much.
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Initial amount if persistent amount of percents of locking, adding rest above it, goes over 100%

DaBomm4
This confuses me, why would having the brakes maxed make a difference while accelerating? Reverse is still accelerating unless I am mistaken. What @CSLACR tested is if you get the same effect or not from 60/5/5 and 5/60/5, and with your theory, that is what you are looking for, right?
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LSD is located after transmission, if axles start turning opposite way, so does LSD working, opposite way. Acceleration in reverse gear activates LSD brake side.
His test was done with 60% against 5%, results are right for that test.
 
OdeFinn
Initial amount if persistent amount of percents of locking, adding rest above it, goes over 100%


LSD is located after transmission, if axles start turning opposite way, so does LSD working, opposite way. Acceleration in reverse gear activates LSD brake side.
His test was done with 60% against 5%, results are right for that test.
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From my understanding of LSDs, that doesn't make sense, just saying.
 
OdeFinn
Sorry, but:
View attachment 353387

Thanks for proofing at PD has modeled mechanical LSD.
Test would do something if testing 60/5/5 and 5/5/60
Click to expand...
You're kidding me right bro? :lol:

You're gonna try to make an ass out of me, while simultaneously claiming that decel is active during full throttle?

It's exactly what everyone said, you just want trouble, and you'll make anything up to find it won't you?
 
CSLACR
You're kidding me right bro? :lol:

You're gonna try to make an ass out of me, while simultaneously claiming that decel is active during full throttle?

It's exactly what everyone said, you just want trouble, and you'll make anything up to find it won't you?
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Could you read few messages more, or study how LSD works.

@DaBomm4 @CSLACR watch this and think of changing reverse gear and what happens then:
 
How about instead of watching your video about real life, we get back to Gran Turismo 6?
Coincidentally, I tried 5/5/60 and the inside wheel turned red. So much for that.
 
CSLACR
If you put a FWD in reverse, park, and turn the wheel, hold the brake and rev the engine, then you release the brake, once you do, wheelspin starts immediately, @ 60/5/5, the inside wheel turns red first. @ 5/60/5, the outside wheel turns red first.
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CSLACR
How about instead of watching your video about real life, we get back to Gran Turismo 6?
Coincidentally, I tried 5/5/60 and the inside wheel turned red. So much for that.
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So you agreed at PD has modeled it right?
 
CSLACR
Oh my. Ok, I will try another way.
FWD in reverse:
@ 60/5/5 - Inside
@ 5/60/5 - Outside
@ 5/5/60 - Inside

That's Gran Turismo 6. If you think that's correct, then sure.
I don't.

Inside.
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So, results are 60/5/5, 5/5/60 AND 5/5/5 spin inside wheel while 5/60/5 spins outside wheel, good find @CSLACR. :cheers:
 
@CSLACR, then you must be happy and enjoy your knowledge of LSD in GT6.
Just wondering why you don't do tests on 1st gear or any going forward?
When you do your tests you should pick some wide body car, stiff suspension and body. Lower it to ground. Then do tests, to get body roll out.
I'm not even trying to explain all things what are playing role what tire burns first etc. But if you're interested you could test it on your own.

Ps. Didn't see pic of that finding, video would be nice.
Ps2. Trying to get some time after work to do few test videos to show.
 
OdeFinn
When you do your tests you should pick some wide body car, stiff suspension and body. Lower it to ground. Then do tests, to get body roll out.
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So do you suggest something like a Mustang Boss with min ride height, and max everything else? Just wondering.
 
OdeFinn
@CSLACR, then you must be happy and enjoy your knowledge of LSD in GT6.
Just wondering why you don't do tests on 1st gear or any going forward?
When you do your tests you should pick some wide body car, stiff suspension and body. Lower it to ground. Then do tests, to get body roll out.
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Forward is harder to quantify. ;)
And yes, I am quite happy with my knowledge of GT6 tuning, and I keep it very separate from my knowledge of real world tuning.

I tested with this VW Scirocco GT24

My most noted results while driving were when I swapped the current setup around from 12/36/5 to 36/12/5, once I did that, I was clearly able to turn the inside wheel red first.
It should be noted it's quite easy to tell when the inside wheel spins first, and it happens a while before it turns red. That's the reason for the very high lsd setting, with lower it spins the inside wheel the whole way around the track.
 
DaBomm4
So do you suggest something like a Mustang Boss with min ride height, and max everything else? Just wondering.
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F40, C6 corvette or some wide and yes maxed out everything, with 0-camber 0-toe, testing on few different compounds, comfort and sports series.
 

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