Initial Torque: What do you do?

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So, literally what you're saying is that 30/30/30 is pretty much the best you're going to get on average. And then the rest depends on the track / suspension / car.

Another thing, now that I get inside tire spin with it at 5, would you think that it IS related to percentages ? Because that would make sense.

Having it set to 5 means it would need 95% of torque transferred to it before it locked the other wheel in, and having it set to 60 would mean it would only need 40% of torque transferred to it before it locked.

?

So I think Im actually gonna be driving with 60/30/30 now so it locks up fast and easy, is a bit violent and still allows a bit of inside wheel spin
 
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Thank you Blueshift, and Will27 for the charts! I'll have to copy and past those for my own personal use.

@Poppins- You've made some pretty big enemies. If your going to say your theory on Initial Torque stick with it, I think that's why you've got so many people arguing against you (not to mention you can be a bit argumentative). So if your going to post, please stick to your original thoughts and ideas., and again lets try to keep the arguments down to a minimum. I want this to be a lively discussion and not a massive flame war.
 
Thank you Blueshift, and Will27 for the charts! I'll have to copy and past those for my own personal use.

@Poppins- You've made some pretty big enemies. If your going to say your theory on Initial Torque stick with it, I think that's why you've got so many people arguing against you (not to mention you can be a bit argumentative). So if your going to post, please stick to your original thoughts and ideas., and again lets try to keep the arguments down to a minimum. I want this to be a lively discussion and not a massive flame war.

I dont really care because I dont like this forum that much anyways, but I did stick with my original theory until Ive tested it for the last few hours and everything has just became so varied and flawed.
 
So, literally what you're saying is that 30/30/30 is pretty much the best you're going to get on average. And then the rest depends on the track / suspension / car.
No, I'm saying some "best accel value for the grip" are within 5-60, same for initial and same for decel. I'm not stating it's 30. On some car, it'll be 30, on other 7, on other 5, on others 38, 52, 60, and so on.

I can't tell for the average since I don't know if there's a lot of 2cv or a lot of FGT in this game.

Another thing, now that I get inside tire spin with it at 5, would you think that it IS related to percentages ? Because that would make sense.
"it" what : initial or accel ?

Accel is the torque diff % it accept before putting a strength of "initial" on the slipping wheel. I don't know the initial units, I searched for them a lot yesterday. It may be % of engine torque.

But if you put a lot of torque to a slipping wheel, either to accelerate in (decel sens.) or decel it (accel sens.), you have to slow down the put torque until you reach 0 again. That's why a lot of initial makes slow unlocking lsd. By making the unlock slow enough, its effect act after you braked, in the apex phase.
The only problem is making it too high gives you **** precision while steering.

Having it set to 5 means it would need 95% of torque transferred to it before it locked the other wheel in, and having it set to 60 would mean it would only need 40% of torque transferred to it before it locked.

?
Initial or accel ?

So I think Im actually gonna be driving with 60/30/30 now so it locks up fast and easy, is a bit violent and still allows a bit of inside wheel spin
Well... Do as you want but you're wrong.
If I make a SR parallel, you are telling the same as if you were telling that all cars need 12kg/mm on both springs. Escudo and 2CV. FGT and Midget II.

This depends of the car, there's no universal value...

@Poppins- You've made some pretty big enemies.
I'm not like that. We disagree, that's all.
 
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So you're saying that having Initial Torque at 5 means it will accept 95% wheel spin difference before putting Accel Amount in % of engine torque to the other wheel.

Because if so that makes complete sense to me and would seem like it fits in perfectly.

Because if I have 5/5/20 It will just always one tire fire because it is accepting the 95% wheel spin and only putting 5% torque to the other wheel causing it to not have enough power to lock up.

And if I have it at 5/60/20 It wont one tire fire because its sending 60% of engine torque to the other wheel causing it to have enough power to lock up.

That would also work for having it at 60/5/20, Because it would only accept 40% wheel spin before sending 5% torque to the other tire, which in turn DOES cause it to lock up because its only 40% wheel spin difference not 95% and 5% torque can make up for that (depending on vehicle obviously, the speed 12 has a lot of torque so makes my results true)

I think this is starting to make a bit of sense if thats what your implying how it works.

Also shows why If its set at 50/50/20 It locks nearly instantly.
 
You don't control inside/outside spin with initial.

Try donuts. Find the accel value that make both tires spins at the same time.

Now put initial 5 while donuting :
- both tires burn at the same moment

Initial at 60 while donuting :
- both tires burn at the same moment.

I made that test two weeks ago, after I couldn't beleive that wasn't like I was thinking it should. It's by speaking with Rotary Junkie, who explained that to me.


The only diff is tires will burn faster with initial 60 than at 5, it's because at 60 you push 60% of the engine torque to one wheel, then 60% to the slowest other wheel and so on (left-rigth-left-rigth after corner exit, do you remember ?)
At initial 5 you'll have 5% torque increments, if not enough 5% more on the same wheel, if not enough 5% on the same wheel so making "even slipping" exact - at least to be under accel sensitivity - but not faster, because it requires a lot of cycles to stop slipping (so, understeering at corner exit).

What you want is the exact quantity on the sliping wheel in a few cycles, "best" is 1 cycle. No understeer, no oversteer. (hey, an idea : Then you can use err... 3/2 of it for 2 cycles, 5/2 of it for 3 cycles and so on maybe ??????)

Then your power of the engine stay perfectly behind your car on both wheels, not lost with no purpose on one wheel only (which is the left-rigth-left-right wheel at high initial or the slowest-slowest-slowest-slowest wheel at low initial).

Also with low initial, the road will eat your tires because the tires doesn't slip enough ("road abrasion"), at 60 the engine torque will eat them because the tires slips too much ("power sliding").
Ideal value (for grip and tires consuption) are what I'm telling to you, or ABS/TCS use.

Now, high initial unlock very slowly, sice you put, says +60% on one side, then still lock, +60% the other side, then still lock, etc.
You can use that to turn around curves when coasting too. This is a LSD technique I used for my NSX S-Zero setup, along with a lot of LSD-autosteer while braking to prevent brutal direction change when coasting (high decel mean loads and loads of engine brake, so a torque barrier that initial won't pass easely while coasting).
That's why high LSD makes better times than low. But with no grip because of too much torque given to wheels, at least high probablity of loosing control. On the NSX, that driving is neat, but it's just for fun I made that car. It give neat times when you understood her driving, like -5-10 sec better than a grippy LSD around Grand Valley.

High LSD are same of low about grip though : grip is bad, that would be oversteering grip and lost engine power. If your car susp setup is perfectly equilibrated, this is called the "fun factor" :)

Now the "high" and "low" LSD frontier depend on each car and setup : the most impactful settings on your LSD are, for me, traction wheels camber and toe, and aero equilibration.

---
When using TCS... I "think", but there you have big "if" and question marks here, that TCS will act upon initial like this : Initial / TCS and give these increments to the slipping wheel instead of all the initial at one moment. But the cycle is also divided by the TCS, so you get more cycles with lower % of torque.

Say you got TCS 3 and initial 9 on a very high rpm/torque car. :D (my zonda).

Instead of having at accel
+9% to the slipping wheel

You'll have (initial (=9) / TCS (=3)), 3 times (=TCS)
+3%/+3%/+3% to the slipping wheel in the same duration. With TCS3, the tires that slip can change 3 times, without TCS, only between +9%.

"alpha strike" is higher with no TCS than without but the total of torque stay the same.

Same, I think the total of unlocking time is multiplied by the TCS value so that's why you get "power lag" after curves. Because you multiplied the # of cycles. So unlocking time stay the same per cycle. You have to get, at TCS3, 3 unlocks, not only 1.

Remember, I have got a lot of question marks around that.
 
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That doesnt really make sense though because when I have 5/5/20 I get inside tire spin and 60/5/20 I dont. So how does initial not have to do with tire spin? It does have to do with speed difference im pretty sure.
 
I think that Initial Torque is the minimum amount of torque (in a %) the slower wheel will take before locking, and that Accel Sens is the amount of torque transferred to the slower wheel (in a % again)

But thats just my opinion now.
 
Thank you Blueshift for your ideas and theories on Initial Torque. And thank you Poppins for your new opinion on Initial Torque. Hopefully you guys (all tuners) will figure out exactly what this odd LSD value really does, and how it does it. I look forward to your next batch of findings.
 
Its driving me insane because now that I think about the %age's it makes sense to me but at the same time seems kind of weird!

But think of it and test it out! It seems like its true?!?!

5/5/20 - inside wheel spin only, 95% slip > 5% torque to other wheel = no lock
5/60/20 - wheels lock up, 95% slip > 60% torque to other wheel = lock
5/30/20 - wheels lock up, some inside spin, 95% slip > 30% torque to other wheel = lock
60/5/20 - wheels lock up, 40% slip > 5% torque to other wheel = lock
60/60/20 - wheels lock up, 40% slip > 60% torque to other wheel = very locked
30/30/20 - wheels lock up, 70% slip > 30% torque to other wheel = lock
30/20/20 - wheels lock up, some inside spin, 70% slip > 20% torque to other wheel = lock
30/50/20 - wheels lock up, 70% slip > 50% torque to other wheel = lock

they all work out and make sense.
 
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I'm now going to explain this, as I believe I really do understand it now:

Initial torque is basically how strongly the driven wheels are coupled before power is applied. It needs to allow difference in rotation to let the car turn.

A more open initial torque value lets the car turn more freely (independent of torque from the engine). Weak initial torque uncouples the wheels without much resistance, and strong initial torque binds them together, before the engine is even running. This is known as preload. The strength of this effect obviously determines the overall power and sensitivity of the differential.

So you open your initial completely... The car turns freely when coasting without power, and the effect is now weak. The effect will only strengthen and begin to couple the wheels (based on the accel decel values) and limit the difference in rotation as it becomes loaded with torque from the engine, but the very low initial strength obviously negates this effect somewhat.

With an very tight initial value, the wheels are coupled strongly before any engine torque is put through the drivetrain, making the car reluctant to turn. Once again, you can now limit the effect engine torque has on the diff. It has this "pre-load" tightness, but engine torque is very strong compared to rotational differences though. So with your tight initial, and minimum accel strength, you now have a diff that is restrictive initially, but doesn't respond much to the great torque from the engine. Under a lot of accelerative force, it is now relatively weak RELATIVE to it's initial strength, and allowing a lot of slip.
 
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Erm...I dont know what all this thread is about?

When I tune LSD on my cars I just keep driving-adjusting-driving.

Its that simple really!

Test drive your car and get it right, who cares how or why it works* lol


*Obviously I care, it was a joke, before anyone has a tantrum ;)
 
I see, But why when I have my Initial set to 60 and Accel set to 5 it locks up under acceleration around a corner, and when its at 5 Initial and 5 Accel again it doesnt lock up and the inside tire spins?

This is why I think it is %ages, as setting it to 5 would cause 95% spin compared to 60 being 40% spin which would make sense why I get inside tire burnout around a corner as well as explaining what you are saying.

so the tires can differ in speed from 95% of each other to 40% of each other, 40% obviously would mean more tight and locked, and the accel and decel settings are based on how much % of engine torque gets transmitted to the slower wheel, from a minimum of 5% to a maximum of 60%.

That would also explain why me having it set at 30/50/30 is working extremely well for me.
 
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Initial torque is basically how strongly the driven wheels are coupled before power is applied. It needs to allow difference in rotation to let the car turn.

A more open initial torque value (higher setting) lets the car turn more freely (independent of torque from the engine). This is known as preload. Weak initial torque uncouples the wheels, and strong initial torque binds them together, before the engine is even running. The strength of this effect obviously determines the overall power and sensitivity of the differential.

I agree with most of your theory, but imho a higher value for initial torque means more binding together. At a higher initial value (say 60) the wheels are bound together stronger, which makes it more difficult to turn in, but also gives stability or even understeer.
At a low value for initial torque the required power to uncouple the wheels is lower, resulting in better turn in but less stability and less understeer. At a lower setting the LSD is more open.
 
I agree with most of your theory, but imho a higher value for initial torque means more binding together. At a higher initial value (say 60) the wheels are bound together stronger, which makes it more difficult to turn in, but also gives stability or even understeer.
At a low value for initial torque the required power to uncouple the wheels is lower, resulting in better turn in but less stability and less understeer. At a lower setting the LSD is more open.

+1

He has it backwards. Lower initial (5) means more ability to turn and higher (60) means more understeer. I have found that in high horsepower rear drive cars, I can use 60 and use on throttle oversteer to get through corners, but it is nowhere near as smooth.
 
+1

He has it backwards. Lower initial (5) means more ability to turn and higher (60) means more understeer. I have found that in high horsepower rear drive cars, I can use 60 and use on throttle oversteer to get through corners, but it is nowhere near as smooth.

I posted my theory right under his as well which makes sense of everything if you look at it. NOT SURE if its correct or not, but thats my thought on the matter as of now and its the only logical and working explanation I can come up for everything.

lower initial (5) = 95% tire speed/torque difference (60) = 40% tire speed/torque difference
 
That doesnt really make sense though because when I have 5/5/20 I get inside tire spin and 60/5/20 I dont. So how does initial not have to do with tire spin? It does have to do with speed difference im pretty sure.

This is because accel is very very low :

@60/5/20, inside start to slip but you only permit low slipping. You'll have 60% of engine torque more to the not slipping wheel on the first cycle. Outside gets a lot of torque and slips a lot @ cycle 1, then at cycle 2, the diff gives more torque on the inside wheel and both wheels slips.

Check if your inside tire is not "sligthly red" before the outside goes red at 60/5/20, then both wheels. That should be the case.
 
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This is because accel is very very low :

@60/5/20, inside start to slip but you only permit low slipping. You'll have 60% of engine torque more to the not slipping wheel on the first cycle. Outside gets a lot of torque and slips a lot @ cycle 1, then at cycle 2, the diff gives more torque on the inside wheel and both wheels slips.

Check if your inside tire is not "sligthly red" before the outside goes red at 60/5/20, then both wheels. That should be the case.

So you are saying that you think it being at 60 permits barely any slip compared to 5 (like i was trying to say with %'s 40% slip compared to 95%)

?

And would you also be saying that because its a low accel, when it has a lot of slip like that it isnt going to lock up really but because I have initial torque set high it doesnt have much slip, causing it to lock up even though its only getting 5% torque from accel to the other wheel?
 
+1

He has it backwards. Lower initial (5) means more ability to turn and higher (60) means more understeer. I have found that in high horsepower rear drive cars, I can use 60 and use on throttle oversteer to get through corners, but it is nowhere near as smooth.
I guess you're talking about FF and 4WD front initial.

How can you have understeer when by locking the diff you powerslides.
Powerslides is too much oversteer, not too few. Result is the same though : outside wall in your head.
 
So you are saying that you think it being at 60 permits barely any slip compared to 5 (like i was trying to say with %'s 40% slip compared to 95%)

?

And would you also be saying that because its a low accel, when it has a lot of slip like that it isnt going to lock up really but because I have initial torque set high it doesnt have much slip, causing it to lock up even though its only getting 5% torque from accel to the other wheel?
Initial don't control the slip, it control the answer of the slip.

If you have to much answer, the answer add slipping to the other side aswell. So now outside slips a lot more than inside. Accel is low so the diff locks again. The answer is 60% more to the less slipping wheel, this time the inside... And all is red.
Not really great when the purpose of the diff is to stabilize your car...

60% more torque mean a power distribution on a 2 wheel car like that : 80% to the less slipping tires, 20% to the most slipping tire. If that 80% torque is more than what lock your diff already with accel 5 (which locks at 52.5% more slipping (not torque)), you're in an endless loop until you die. On a 100 hp car it mean 80hp "left" and 20 hp "rigth", which is okay, but with a 1000hp car it mean 800hp "left" and 200hp "rigth", since the rpm is from the same engine (rpm*torque = hp).
You can slow enough the slipping wheel that way and then come back okay, but you'll slip in any curve : online you are the last each time. GT book tell this is oldschool LSD methods (high initial, low accel). Today, cars use low initial/"high" accel as for accel slipping.

Decel in more complicated... I don't understand it very well yet.

"100hp lift 750kg of 1 meter in 1 second" (err, I'm not really sure there), so imagine what is 600hp more on one side of a 1000kg car. An orbital take-off, but in a horizontal direction. :D that's why most high HP car have low initial unless they are glued to the road by their wings and toe/camber (toe/camber is a double edge sword in that purpose)


Accel/decel control the slipping point.
Low accel mean not much slipping allowed before the diff locks and apply initial torque to the not slipping wheel (or remove from the slipping wheel I don't remember, the result is the same, power goes to the other side with too much initial).

Please re-read the link I posted in the zonda topic, it is really well explained with scientific formulas in it.
 
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OR are you saying that 60 for Initial Torque means 60% transmitted to the opposite slower wheel when it locks up, and the Sensitivity is the amount of slip permitted (5 means 95% slip? )
 
That makes complete and perfect sense to me now.

Low Initial Torque means only 5% of torque transmitted to other side, and High means 60% transmitted, Where Low Accel means 95% slip, and High Accel means 40% slip.

This what you are saying? Because it would match up with my tests at the bottom of the previous page as well. :)

Gonna change my TVR to 50/60/20 to test out that.
 
I still think that it is the Opposite and Initial Torque is how much slip there is and Accel is how much torque is transmitted. :S

Just because when I have my TVR at 5/60/20, it locks right away, where you said it should slip more then 5/5/20 which isnt how it is for me because 5/5/20 spins the inside tire. (thats what makes me think that accel is %age of slip because 95% would mean inside tire spinning) As well as when I have it at 50/50/20 It locks right away, and at 50/5/20 It locks right away as well which would be because of what you said and it having only 50% tire slip lets the 5% torque burn both tires.
 
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I still think that it is the Opposite and Initial Torque is how much slip there is and Accel is how much torque is transmitted. :S
Ah ****, we only agreed 10 seconds.

test, test and re-test, I'm 100% sure of me now.

You mis-read the answer and the cause on your LSD.

I though like this one-two month ago and I was wrong.
 
Well my problem is that if I have it at 5/60/20 or the opposite at 60/5/20 it pretty much acts the same hahahahahah which makes it really tough for me to tell which one does which :P
 
Just because when I have my TVR at 5/60/20, it locks right away, where you said it should slip more then 5/5/20

This is the opposite problem :

At 60 accel you correct the not slipping wheel only when the slipping wheel spins 5 times more than the less slipping wheel, so almost never. So outside slips each time (since all the weigth is outside).

At 5 you correct it when it turn 1.1 more of the not slipping wheel : rigth away. You apply a low more torque, 52.5% to the unslipping wheel and 47.5% and voila this is done. And even this migth be too much initial to make the inside wheel to be corrected... If it reach 1.1 turn. that depends of the car's hp, dimension , camber, aero, damper, etc.

But low LSD are not optimal : you'll have "understeering grip" problem.
 
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Well my problem is that if I have it at 5/60/20 or the opposite at 60/5/20 it pretty much acts the same hahahahahah which makes it really tough for me to tell which one does which :P

60/5/x is oldschool, 5/60/x is more 1980 and after.

60/x/y is very dangerous. It makes 80% of the hp to the not slipping wheel and 20% on the slipping tires. It slow the slipping tire, yes, but it can be fatal on a 1000hp car.
 
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