This is a write up from a guy on a different game GT Legends but it should help you out....
Dampers
Very important parts for tuning the car.
We have a bump and a rebound damper setting for the front and the rear (no assymmetric setting for left and right).
The
bump damper sets the damping when the car goes
onto a bump, so when the
tyres are pushed in
The
rebound damper sets the damping when the
tyres move outwards (down when the car is the right way up)
Here's the point where one really have to understand the weight transfer:
- When you're braking the weight goes - or wants to go - to the front
- When accelerating, the weight wants to go to the rear
Now dampers - as their name suggest, dampen this somewhat. In practice this means, with a little damper setting we can change how the car reacts to braking, or acceleration.
I have to mention again, that extreme cases are not to be counted with. If you smash the pedal on corner out, you'll lose control: you can spin almost any RWD car, especially racecars. If you lock the wheels under braking, again, you can and will lose control of the car.
But if you're otherwise driving nicely, you know how to approach the corner slowly easing up on the brake, and know how much throttle to apply in your car to get acceleration but not wheelspin...then you might want the car to act to your liking.
Oversteeer is usually wanted to a level, as
it makes the car turn. And that's what we want, now dont' we? Well, not everybody...

But I'll talk about how to get oversteer, and anybody can deduct easily how to get understeer. All you have to do is exactly the opposite in a given situation; in other words, just replace 'soften' with 'harden' and vice versa.
So we want more overster under braking ...
If the car understeers corner-in (under braking), means the front grip is lower into corners, means there's not enough weight on the front. In this case we can try to soften up the front bump damper and/or the rear rebound damper. If you're at the softest, you may need to harden the whole set a bit or simply try hardening the front rebound and/or rear bump.
When we want more oversteer when accelerating out...
If the car understeers corner-out, means again there's a lack of front grip. But this time it's the rear damper and the front rebound playing more, because you're accelerating, and the weight wants to move to the rear. So try to harden the rear bump and/or front rebound to force the weight to stay a bit longer at the front

.
Now I've no scientific method to find the sweet spot, I usually go around trying - again the lack of setting is a bliss. We have only 4 notches of setting to play with.
