Help needed for some LSD fine-tuning

  • Thread starter Thread starter Gupster74
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Gupster74

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Before the fanboys start telling me how lazy i am and that there's a GAZILLION threads on lsd's, i know!!! But after reading a million of them im still none the wiser as to which parameters to alter so i'll tell you the car and my driving style preferences and i'll GLADLY accept any help
I'm driving an ARTA NSX JGTC, completely stock.
My settings are thus:
R-height(f/r): -5/0
Springs: 13.8/14.4
Dampers(R): 8/8
Dampers(C): 6/7
Roll-bars: 4/3
Camber: 2.0/1.0
Toe: -0.10/-0.05
Lsd 7/35/7
Brakes: 5/3
Here is my problem.
I like my cars little oversteery, and i tend to trail-brake a little, then coast thru the apex, and throttle out hard. I want plenty of grip under acceleration but find the car understeering horrifically under deceleration!
Which setting is wrong????
Note: i kno the toe i have set has an effect but i really would like to keep this as is!
 
Gupster74
Brakes: 5/3
I like my cars little oversteery, and i tend to trail-brake a little, then coast thru the apex, and throttle out hard. I want plenty of grip under acceleration but find the car understeering horrifically under deceleration!
Click to expand...

All opinions based purely on how *I* like my cars to handle - never really raed the tuning forum!

Switch your brake bias so it's biased rearward rather than frontward, should make you less likely to lock the fronts.

Could try adding more rear camber (+1/1.5 degrees) for more grip exiting the corner. You can add a touch more front camber too.

Also check your rear wing, if it's set to max, back it off so it's less than 15 pts higher than the front. You'll turn in better, but maybe loose some rear stability.
EDIT - just read it's totally stock...max out the front wing, much less understeer.

Oh, and your roll bar's stiffer at the front, try evening it out or making the rear stronger in stages. If you like oversteer bias you want the back stiffer.
 
someone suggesting more camber on rears is odd.. depending on the track, the less camber you can put on your rears the faster you will go on the straights, even .5 rear camber can be the difference of 10kmph on straights.. which is win or lose depending on what cars you're racing :P
 
As far as I understand, the more camber you have, the less braking power you get. If anything, you want to reduce rear camber, perhaps to 0.5 or less, therefore shifting balance rearward slightly, and reducing braking understeer. (Please say so if I'm wrong on this)
 
This is from the book:

APEX: Ultimate Car Guide

"Initial Torque decides the point at which LSD kicks in. The higher it is, the more easily the LSD will lock, and the more responsive acceleration will be. The lower the initial torque, the more slowly the LSD will take effect.

Generally speaking, increasing the initial torque will accentuate the handling peculiarities of the vehicle's drivetrain layout. Therefore, oversteer will be increased in rear-wheel drive cars, and understeer will be increased in cars with front-wheel drive. Although this improves traction in both cases, it will make turning more difficult. As such, initial torque adjustments should be made with the desired handling requirements in mind.

Another setting that can be adjusted is how the LSD behaves during acceleration ad deceleration. The acceleration setting governs the effectiveness of the LSD when stepping on the accelerator, and the stronger it is, the more drive power is transmitted to the wheels, and the more likely the car will be able to clear corners. However, this will also accentuate any handling peculiarities, and getting the car to point in the right direction needed to exit the corner may require some skill.

The deceleration setting governs the effectiveness of the LSD when the accelerator is released. The stronger it is, the more stable it will be upon entry into a corner while breaking. This allows you to go into the turn very fast, because you can keep breaking longer than you would otherwise. However, this makes turning more difficult, and is only recommended for advanced drivers who are skilled at compensating for initial understeer."
 
Raitziger
I would "turn off" the LSD to figure out if it causes the problem or not.
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If you can disable the lsd on a race car then thats news to me. It comes fitted as standard. And now i'm not actually sure its my car. I'll clarify my situation more clearly.
Doing the Suzuka 1000k in the Arta NSX (super gt). And just occasionally the car just ploughs straight on under deceleration at certain corners (namely the 2nd right in the left/right/left/right sequence after the 1st bend and the corner coming onto the start/finish straight!!)
Now i know your prob thinking its worn tires, but no, it happens randomly on fresh/part worn/ knackered ones!! And i have to brake heavily just to get the car to turn.
ODD NO !!! ?:confused:

PS: i realised i should've put this on the tuning forum but did it via (not so)smart phone and not sure how to move it. BTW, thanks for your help Denise
 
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Corpsey
someone suggesting more camber on rears is odd.. depending on the track, the less camber you can put on your rears the faster you will go on the straights, even .5 rear camber can be the difference of 10kmph on straights.. which is win or lose depending on what cars you're racing :P
Click to expand...

It's about a balance i guess, and varies with the track and car...if you gain 5mph in cornering speed through the increased camber, it *can* make up for the lost straight line traction.

I prefer twisty tracks with few straights, and find more camber gives me more grip and higher speeds in the corners, and I can put the power down earlier exiting the corner. This is at the expense of top speed on the straight, but on most tracks you spend a lot more time cornering than at top speed on a straight...but you need a different setup for oval racing, where you spend a lot more time at Vmax on a straight.

The actual values seem to vary from car to car as well, some cars like more camber, some it just hinders. It seems PD actually have modelled some of how the suspension design changes from car to car.
 

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