LSD Tuning question... please help!

[tirple]

ok so I have gone through Scaff's tuning guide but still has a little bit of question...

Case I.

Say you are driving a rear wheel drive car going into a left turn.
Before entering the corner when breaking, your right rear wheel starts to smoke up.

SO in this situation, should I
a. Increase the decel setting on LSD
b. Decrease the decel setting on LSD
c. Do something to the suspension?
d. something else

Case II.

You are driving a rear wheel drive car going into a left turn.
after passing apex, you hit gas and your right rear wheel starts to smoke up.

SO in this situation, should I
a. Increase the accel setting on LSD
b. Decrease the accel setting on LSD
c. Do something to the suspension?
d. something else

Please help as I am running out of ideas.... a short answer would be very helpful

 

[oppositelock]

I'd try softening the rear sway bar first. If it's too hard it could cause the inside tire to lift, thereby causing it to lock or spin. Then I would try raising both LSD settings.

 

[nomis3613]

Say you are driving a rear wheel drive car going into a left turn. Before entering the corner when breaking, your right rear wheel starts to smoke up.

Are you sure the outside wheel is locking? That is quite strange, normally it is the inside wheel that locks(because of weight transfer). All I can suggest is try reducing the rear brake strength.

You are driving a rear wheel drive car going into a left turn. after passing apex, you hit gas and your right rear wheel starts to smoke up.

Again, are you sure it's the outside wheel?? If so... ummm... try reducing the LSD accel.

Other ideas: are these examples on bumpy tracks? Are your TV speakers perhaps connected backwards so you are hearing the screeching from the wrong side of the car?

 

[DiaGTR]

Case I.
c. Do something to the suspension?
d. something else

Case II.
b. Decrease the accel setting on LSD

Case I is strange and I wouldn't touch the LSD because of that.. brakes, suspension.. yes, but not LSD. Or is it the right front wheel?..

Case II will help you with the smoke and will prevent your rear from oversteer, but it will affect your corner radius also.

 

[tirple]

Thanks for everybody's input, I really appreciate it.

Are you sure the outside wheel is locking? That is quite strange, normally it is the inside wheel that locks(because of weight transfer). All I can suggest is try reducing the rear brake strength.

I'm pretty sure my outside rear wheel turns red on the screen when I hit the break and it makes the car go kinda sideways.(usually depends on the curvature of the turn it generally goes that direction and pointing Apex Not really incontrollable, but it's on the verge of losing control) I'll give it a shot.

Other ideas: are these examples on bumpy tracks? Are your TV speakers perhaps connected backwards so you are hearing the screeching from the wrong side of the car?

Ugh... do you consider deep forest bumpy? I usually setup my car there.

As for the speaker... I might be a noob but not that noob to make rookie mistakes like that.... I hope

Case I is strange and I wouldn't touch the LSD because of that.. brakes, suspension.. yes, but not LSD. Or is it the right front wheel?..

Actually front outside sometimes smokes up too, I'm strating to think maybe it's the break.

Case II will help you with the smoke and will prevent your rear from oversteer, but it will affect your corner radius also.

Ok so this brought up another question, if you go all the way down to 5 (or super low) do you increase or decrease your init. Torq? Are there any relevancy or...?

 

[DiaGTR]

Actually front outside sometimes smokes up too, I'm strating to think maybe it's the break.

Adjust your brakes more to the front. It will help you to keep the car straight while braking.

Ok so this brought up another question, if you go all the way down to 5 (or super low) do you increase or decrease your init. Torq? Are there any relevancy or...?

It depend on the car. So when there is a car with really bad corner exit, like the Nomad Diablo or the Cobra, than I'm going to increase it. A higher init. torque will allow you to keep accel setting a bit higher (better radius). Its because of the softer torque entrie when you begin to accelerate.

 

[Rotary Junkie]

Adjust your brakes more to the front. It will help you to keep the car straight while braking.

Wha? If both ends are having issues under braking, REDUCING brake pressure at both ends may be advisable. Certainly not increasing front brake pressure. ABS off, you have lockup very early at almost any setting above about 4 on the front and above 2-3 on the rear can make it skittish as speeds drop. With it on, there's rarely too much rear brake pressure... And when there is, it's due to excessive weight transfer and can be solved via other settings.

It depend on the car. So when there is a car with really bad corner exit, like the Nomad Diablo or the Cobra, than I'm going to increase it. A higher init. torque will allow you to keep accel setting a bit higher (better radius). Its because of the softer torque entrie when you begin to accelerate.

A higher accel value will create understeer until the tires break away, at which point it will snap harder into oversteer, but it will put more power to the ground when there is a wheel speed difference.

 

[DiaGTR]

Wha? Certainly not increasing front brake pressure.

There was not even a word that said to increase brake pressure. Suspension was mentioned before.

A higher accel value will create understeer until the tires break away, at which point it will snap harder into oversteer, but it will put more power to the ground when there is a wheel speed difference.

Before speaking about oversteer and understeer, you should read the previous text. What is "a bit higher" for you when your read something like this > "all the way down to 5 (or super low)"? Ohh and LSD of a front wheel drive works not in the same way as the one of a rear wheel drive..

 

[nomis3613]

I'm pretty sure my outside rear wheel turns red on the screen when I hit the break and it makes the car go kinda sideways.(usually depends on the curvature of the turn it generally goes that direction and pointing Apex Not really incontrollable, but it's on the verge of losing control) I'll give it a shot.


Ugh... do you consider deep forest bumpy? I usually setup my car there.

Ahhh I thought you were detecting wheel slip from the sound, but yeah the diagram is a different story. Deep Forest is bumpy, I was thinking maybe a bump is causing the outside tyre to lose grip but it doesn't sound like that's the problem. Still, I find it very strange that the outside wheels are slipping.

if you go all the way down to 5 (or super low) do you increase or decrease your init. Torq? Are there any relevancy or...?

LSD settings are very much a matter of personal preference, so just experiment until you find what you like the feel of. Yes, initial and accel are related, so try different combinations

Adjust your brakes more to the front. It will help you to keep the car straight while braking.

There was not even a word that said to increase brake pressure. Suspension was mentioned before.

???
Ummm you did mention the brakes before. Maybe you were meaning to reduce the rear (instead of increase the front), but that wasn't clear so RJ's reply about not increasing brake pressure was a valid point.

Ohh and LSD of a front wheel drive works not in the same way as the one of a rear wheel drive..

This is true, but the whole thread is about RWD (and RJ's comment which you quoted is true for RWD IMHO) so I'm not sure why you brought this up?

Wha? If both ends are having issues under braking, REDUCING brake pressure at both ends may be advisable. Certainly not increasing front brake pressure. ABS off, you have lockup very early at almost any setting above about 4 on the front and above 2-3 on the rear can make it skittish as speeds drop. With it on, there's rarely too much rear brake pressure... And when there is, it's due to excessive weight transfer and can be solved via other settings.



A higher accel value will create understeer until the tires break away, at which point it will snap harder into oversteer, but it will put more power to the ground when there is a wheel speed difference.

+1 to all of this. Tirple, some people like to use a lot of LSD initial (instead of accel) because this means there is less change in the car's behavior when you apply/release the throttle.

Hope this helps.

Simon

 

[DiaGTR]

???
Ummm you did mention the brakes before. Maybe you were meaning to reduce the rear (instead of increase the front), but that wasn't clear so RJ's reply about not increasing brake pressure was a valid point.
...
This is true, but the whole thread is about RWD (and RJ's comment which you quoted is true for RWD IMHO) so I'm not sure why you brought this up?

I mentioned brakes and suspension in my first post. But I will never give tips for suspension (weight transfer), since I don't know for which car. This car is going sideways while braking. My post said only how to keep it straight with brakes, nothing more.

Yes it was true for RWD. But was there a question about oversteer or understeer somewhere? There are many other ways to control oversteer/understeer. So I didn't see the reason for his comment about accel value, when I was speaking about init. torque AND very low accel value.

 

[Rotary Junkie]

Yes it was true for RWD. But was there a question about oversteer or understeer somewhere? There are many other ways to control oversteer/understeer. So I didn't see the reason for his comment about accel value, when I was speaking about init. torque AND very low accel value.

I was rebutting your notion that a higher accel value would decrease the turning radius of the car under acceleration... Which is untrue unless you're spending your time going around track the slow way (sideways).

There are VERY many ways to control the vehicle's tendencies, but seeing as the thread is dedicated to LSD tuning it is a moot point to discuss them. The LSD's effects do not change what is needed for the suspension, but the settings can help "trim" a vehicle which has certain natural tendencies that fixing via suspension causes other, more undesireable effects.

 

[DiaGTR]

This note was there to prevent the understeer caused from very low accel value, where the inside wheel begin to smoke. (accelerating at corner exit) Just wanted to say that a low acces is not needed for better corner exit, when the car has a behavior to go sideways at this point. The initial value is a big help there.

And to be honest, I know what LSD is doing. I'm messing around with it since I play GT. Its the first thing you have to do when you play with pad..

 

[BlueShift]

a short answer would be very helpful

I.c.d
II.b.c.d

^^

I : remove some brake points, step less on the brake pedal, adjust your rear camber to something like 1° or less (I put -0.4 on a Jaguar Type E and never go more than -3°, but if you have that sort of problem stay in +/- -0.6°), wider your front and rear dampers difference (2-3 front, 3 or more in the rear), increase initial +8 points or something like this or remove some 4 pts in decel for more braking stability.

II : -4 to accel and/or to initial LSD (initial seems to be "should i boost/should i nerf" problem there), step less on the accel pedal, remove some camber at the rear (traction wheels give too much power to the road and slip, therefor you need a flatter tire contact), wider your rear damper difference, remove some kg on front/rear train's springs and/or follow the weigth distribution (hehehe) when considering true RH (hehehe) and SR (hehehe).
And another thing, yes, it's after apex, yes this comes when you accelerate, yes I know that. But try this, it migth work on some strange cases : remove 1-2 rear brakes points. Magic trick, isn't it ?

Among so more other things (rear toe to 0.15/0.2, but please avoid that, you'll have to remove some camber. Use toe only if it's your last solution or you're with a group C or that kind of "wanna have driving aids anyway" car). You have another hardcore solution if your car is in the 400hp : raise the front RH say 20 pts higher than rear's.

If the outside wheel make noise, you're oversteering. There's plenty of solutions, really.

True RH, unflat RH weigth distribution and their impacts on dampers is my best kept secret I will give out someday after the tuning competition starts

Also, maybe you have to redo your car because you're in an impass, you felt or neglicate some important things in your tuning process. Note your current setup, repair your car and restart from default.
I restarted 3 times the Stingray (which is one of my best setups but nobody tried it here ). And I have to redo my ZZII 'cause there's still understeer problems that prevent me from winning against my friends


By the way... What are your antiroll settings ?

 

[BlueShift]

Its the first thing you have to do when you play with pad..

Nope, it's always the suspension. If you modify your suspension/camber/toe, LSD is impacted. If you modify your LSD, the suspension isn't (but for the toe/camber).

Camber/toe is very dependant on the LSD, but suspension is independant if you don't change it after the basic needs are covered. Consider LSD as fine tuning, aero/camber as medium, and brakes/suspension/toe as heavy tuning.
If you change your suspension after LSD tuning, your LSD is all messed up, if you change your LSD after the suspension is made, your suspension stays (almost) the same (but for front/rear damper compression speeds, on some rare cases).

The first thing you tune should always be the SR/RH because it's the heavier part and Aero because it's the less dependant part to others (to 95%/95% then go basic susp tuning then to 99%/95% or 95%/99% depending on your oversteer/understeer at high speeds and after that to more refined values after LSD is made more or less).

 

[DiaGTR]

Consider LSD as fine tuning

Yep! WHEN you are going to tune a car. But when you just wanna drive a car with standard settings, than is the LSD that thing that can make the car controllable for pad drivers. Or why do people spin around the track, over and over..

You are right with that what you said, for a tuned car! But it wasn't meant for such one (As example Carlsonic IMPUL Arcade at Trial Mountain, left corner after the long straight... Take the same car with standard setting, adjust the LSD and you will see the fast result)

I know, its not the best tip, there are better ones, but this one works always for pad drivers who don't wanna work with settings..

 

[nomis3613]

Hang on guys, re-reading the first few posts has made me think we might need to go back to square one for tirple:

I'm pretty sure my outside rear wheel turns red on the screen when I hit the break and it makes the car go kinda sideways.

I've just done some laps while keeping an eye on the tyre gauge and now I'm doubtful that what is happening is actually wheelspin or locked wheels. The general consensus on the tyre gauge going red is that it means the tyre is overheated.

The overheating can be from cornering, braking or accelerating too hard and it does not necessarily mean you have wheelspin or brake lockup. I think in your case (because of the outside wheel going red) it is related to cornering loads being too high.

Even though this thread is called "LSD tuning", I think the problem is best solved with suspension settings. Or do you have a reason you'd like to try and stick to LSD settings only?

What car is it? How much power? Which tyres?

 

[BlueShift]

the best thing should be the guy giving out his setup, car and hp/weigth.