Differential settings - please :-)

[BrunoBæ]

Can I get some help here?
I have been experimenting with diff settings in the gearbox for the Classic Gen1 model1 F1 car.
And when I enable the Clutch LSD then I can NOT feel much difference when I lower/raise the power or coast ramp.

If I instead enables the Geared LSD then there absolutely is a difference if I change the correlating Bias Ratios Power/Coast - but because of the abrubt change in car behavioring entering/exiting a corner I would much prefer to be able to use the Clutch LSD mode.

Result

 

[BillGuy]

The thing that has me tripped up is that even for the LSD, the same three settings we have from AMS 1 are different units now in AMS 2. Could that potentially mean that the values for power/coast and preload might be intended to work opposite of how they did in AMS 1?

 

[BrunoBæ]

Thanks for responding so fast.
But I have never owned AMS1 - so...
My problem is that I compare to both iRacing, ACC and partly rF2.
Where something like the Clutch LSD was working - somewhat.
"somewhat" - because in rF2 as example I was never sure if the coast side had more than placebo influence

 

[BillGuy]

Ah, since you’ve never owned AMS1 you might want to take a look at the diff section from the pinned “How to Set Your Car Up” guide over in the AMS1 forum. That way you’ll at least have some baseline in the event you see any further discussion of things being the same or opposite in AMS2.

The relevant info not mentioned in the guide is that in AMS1 power and coast settings are a % value and preload has no units assigned to it at all. It's just a number.

https://www.racedepartment.com/threads/automobilista-how-to-set-your-car-up.132909/#post-2419185

 

[BillGuy]

I took the F-Classic G3M1 out for a pair of 5 lap drives at Kyalami. I meant to do the same car you used but remembered which generation you were in incorrectly.

Both tests were done with LSD=On, Preload=20Nm, and Clutches=4. 20 was chosen for Preload simply because it’s two clicks up from nothing. Clutches at 4 is the default value which I left since I have zero experience or knowledge what the effect is supposed to be.

My first test had power/coast at 75/25 degrees with the second test the opposite with power at 25 and coast at 75.

To me the second test felt distinctly more like what I would want from a diff. Help with turn-in during throttle-off and help with exiting during power-on. Having said that, the feeling between the first and second tests was not one of the effects being “opposite” of each other like you might expecting flipping the power and coast numbers.

I could go on, but two five lap stints in a single car I’m only moderately familiar with probably doesn’t warrant any more of an impression than I just stated.

 

[Shadak]

if you do Gear based diff, its more distinct due to limited settings and no preload to smooth things out.

clutch is reversed for the 2 bits, basically less angle is more locking. So less coast is more understeer while more power is more understeer on-throttle. A lot of cars are set to be a bit understeery (if not most). Preload isnt affected by number of clutches btw. If you want a more aggressive turn in, decrease to 2 and high coast angle. This locks less off-throttle, letting wheels have different speeds more.

 

[BrunoBæ]

Thanks @BillGuy - multo appreciated and useable
And thank you for testing it out on track.

And thanks to @Shadak for taking the time to explain specially "less angle is more locking" because if I compare as example iRacing and rF2 then they are completely the opposite conserning explaining if higher numbers should give more lock or less lock.
Hehe Sorry I cant remember which of them says which

CatsAreTheWorstDogs: @Shadak I have to admit that eventhough I feel quite at home messing with diff settings then I have allways been unsure about the relation between preload and clutches. Hehe your "Preload isnt affected by number of clutches btw" is stopping this unsure-ness

CatsAreTheWorstDogs2: The reason I mess with these settings is because I use a fully handcontrolled wheel (have to because of legs) - and therefore I can only drive cars where it is possible via diff settings to get the car to rotate (oversteer) "by itself " at the entrance of a corner - as soon as I gear down and close the throttle. Because Im unable to turn the wheel much at that point if I want to have control over the braking + gear down and throtteling.

 

[Shadak]

cheers mate, im not an engineer so hopefully i dont understand it wrong lol.

the number of clutches are the number of actual physical plates, so effectiveness of power and coast locking. Preload is a set strength of locking regardless of those other settings, it just locks whatever NM is clicked at.

i think various sims take various approach, i believe the correct mechanical way is the angles, as thats how its really done on LSDs if im not mistaken.

 

[BrunoBæ]

i think various sims take various approach, i believe the correct mechanical way is the angles, as thats how its really done on LSDs if im not mistaken.

I think this part of your comment is the urgent one.
Because one thing is to lean too much on how these diff settings does work in RL - but another is how realistic the different sims does implement/ replicate the physics behind the settings.
If we as example take the preload then I have seen explanations from RL saying that the preload is NOT just some constant loaded "weight" that will be functioning all the time - but also a setting that controls how fast/slow the Power and Coast lockings are functioning.

CatsAreTheWorstDogs: Personally I honestly dont think any sim use the Preload parameter to anything else than some static and simple adding or decreasing the Power and Coast parameters. IE it has nothing to do with the speed the P/C locks are effectuated - like in RL.

 

[Shadak]

oh yes, preload should be something that i imagine smooths out the transition and affects it, its just the setting thats separate. Compared to Geared which when you go between coast and throttle cam be a bit "jumpy"

 

[BillGuy]

I’m still confused on whether you “should” use preload, clutches, or both to smooth out the transition between power and coast.

In principle (in the real world) you would think clutches because...well...that's what a clutch does. It gradually transmits a torque from input to output. But in AMS1 we only had the preload setting in the diff and it was definitely the one adjustment that you used to soften the transition between power and coast. That raises the question of whether or not this line of reasoning has been carried forward to AMS 2.

 

[Shadak]

i think the main thing to look for is to make sure you dont get a snappy behaviour mid corner.

 

[BrunoBæ]

@Shadak
Thanks for insisting
But I just read up about the diff settings in AMS1 in your link(automobilista-how-to-set-your-car-up)
And acording to this its the opposite of how I read your post.
If I may add then the reason for starting this thread was that as I understood the power and coast settings then:
the LOWEST numbers in Power and Coast would result in maximum oversteer entering a corner and maximum understeer exiting a corner.

if you do Gear based diff, its more distinct due to limited settings and no preload to smooth things out.
clutch(based) is reversed for the 2 bits, basically less angle is more locking.

So less coast is more understeer while more power is more understeer on-throttle.

Conclusion: More Power angle = more Acceleration Understeer.
Conclusion: More Coast angle = more Deacceleration Oversteer.

Automobilista - How to Set Your Car Up!

Greetings fellow racers! As you begin to become more competent and faster SimRacers, the more important the car setup options become. This is because as you get quicker, the harder it becomes to find time gains. This is known as the Law of Diminishing Returns. The default setup can only get you...

www.racedepartment.com

Power
•A higher percentage value will result in the differential locking more quickly when power is applied.
This will result in the rear (or front) wheels spinning at more similar speeds which will result in greater oversteer.

Coast
•The Diff Coast setting affects the car behaviour when you are OFF the throttle.
•This is particularly helpful during corner entry as you can adjust it to help get the car to rotate more easily,
•A lower percentage of coast = more off-throttle oversteer.

CatsAreTheWorstDogs: Im absolutely not quarrelling for quarrelling sake - but am trying to understand which values for coast and power gives most oversteer entering and most understeer exiting a corner. The midcorner thing Ill fight afterwards

 

[Shadak]

it wasnt my link

i know what you mean, but percentage isnt the same as angle. ams1 had a different engine.

 

[BrunoBæ]

Both of you - lets dont "waste time" on the preload and soften out thing - because what is more urgent is if it is lowering the numbers or raising the numbers in Coast and Power that will give me the characteristic I want. IE Oversteer at entrance and Understeer at exit of corners.

EDIT:

but percentage isnt the same as angle

No I had a suspicion of that but I can garantee that both in the iRacing and rF2 camp numbers and angles are completely confused.

 

[BillGuy]

A bit of a summary of the pending questions, if I may. Even just keeping the discussion to power and coast settings. Some of this has already been addressed in prior posts. I just thought a summary of the current situation might be helpful as we search for a collective overall understanding.

First
In AMS 1 the numeric values you plugged into the power and coast settings worked in “opposite directions”. A lower numeric value on coast equaled a more pronounced effect. A higher numeric value on power equaled a more pronounced effect.

We need to determine if the same still holds true in AMS 2 or if you should (in theory) be changing both the power and coast settings in the “same direction” to achieve more pronounced effects for each.

Second
The units of the power and coast adjustments in AMS 1 and AMS 2 are different using percentages and degrees respectively. This potentially makes carrying over any assumptions about AMS 1 adjustment principles to AMS 2 invalid.

We need to determine which numeric “direction” (larger or smaller angle values) are needed to get a more pronounced effect from the settings. This will of course be directly related to the first point mentioned above.

Third
It’s possible that the amount of effect that’s felt from the power and coast adjustments may vary between cars even when you have the same numeric values set for power and coast or the same relative difference between the numeric values.

The reasons why this may exist are probably a discussion in themselves. Also, if this variation does exist, it probably doesn’t change how the diff adjustments actually work. It’s just important to remember that this “variation” or “scaling factor” could exist so it’s probably best not to judge the magnitudes of various power/coast adjustments on anything other than the specific car you’re trying them with. At least not until there is a reasonable collective body of knowledge built up.

 

[Shadak]

So I just wanted to do a test. This video is 2 together with no editing so 2nd starts right after, its the same corner in Jerez. Now first bit is with low preload (20), high coast angle (85), 2 clutch plates. This is extremely low locking, you can see the turn in is easy and not a lot of steering required, I even had to correct it away from inside a bit. I let it coast on purpose. The 2nd bit is high preload (about 250 i think), low coast angle (25). 10 plates, very high locking. As you can see, I need more steering and it understeers away kind of, and even snap oversteers due to high locking on power. The Clutch LSD to me seems smoother and not as playful - oversteery on coast - as Geared. But also safer

 

[BrunoBæ]

Hi guys these are my conclusions after testing it out in the classic F1 gen1 mod2(?).
In the Clutch mode!

High Power Angle = Acceleration heavy Oversteer
Mid Power Angle = Acceleration slight oversteer
Min Power Angle = Acceleration slight understeer/neutr

High Coarse angle = Decelleration Neutral
Mid Coarse angle = Decelleration Neutral
Min Coarse angle = Decelleration slight understeer/neutr

Ill check the video out to see if the behaviour correlate.

CatsAreTheWorstDogs: Its easy (somewhat) to feel the impact of the power settings - while the coast settings is difficult to feel.

EDIT: Not much to see in the video Shadak
OK after reading your explanation it makes more sense

 

[BrunoBæ]

We need to determine which numeric “direction” (larger or smaller angle values) are needed to get a more pronounced effect from the settings. This will of course be directly related to the first point mentioned above.

Good thinking Bill.
At least for the power angle its pretty easy to conclude from my test - while with some caution its also possible with the coast angle.
Me think

 

[BillGuy]

I think I’m going to bow out of the conversation at this point at least as far as testing is concerned. My wheel is a bit of an oddball and I have a suspicion that the way the game is handling it may not really be giving me a true impression of differential behavior. At least where slow tight corners are concerned and that’s obviously where you’re most likely to be looking for help from the diff.

This isn’t a knock against the game BTW. The behavior I experience is manageable and predictable. My gut just tells me that some of what I experience may be "controller compensation" and not exclusively just the sim's modeling of the driveline.