How to tune properly? [WIP]

One thing is for sure, there will be a moment where you will have to upgrade any of your rides. But like with any proper sim racer, upgrades do mean that your car has to be tuned in order to adapt to its new stats properly. If you don't have too much knowledge on how the game works regarding tuning, you can grasp an idea on how to by either reading the information the game gives to you, or if you want a more concise way to know how to tune your cars, follow along this guide.

Introduction [WIP]

When getting a new ride for a car

If you’re just getting into tuning, it can be difficult to know which settings to start with, and what to test for. Everyone has their own preferences, and what works for me may not work for you.

The most important step is to try the car before making any suspension and LSD changes, and make observations. Make sure to set up the gearbox, increase downforce and turn down ASM and TCS first. How well does the car turn around wide corners? Does the car lose composure when entering slow sharp corners? Does the car feel unstable when exiting?

You’ll also need to check your car’s tyre wear rate to see if it wears through its front or rear tyres faster. I usually test this in the Tokyo R246 race in All Japan GT Championship Amateur, as it’s a 5-lap event on a relatively long track. Make sure the car has the right tyres equipped before tuning the suspension.

Your choice of track to test your settings on will also make a big difference. From the Run and Settings option in your garage, you have a variety of tracks that you can drive on. This is the most efficient way to tune and test your car.

Each of them will test the car in different ways; Laguna Seca’s sharp corners will reveal any power oversteer issues while the car exits corners in 1st gear and 2nd gear, Midfield Raceway tests the car’s ability to make fast wide turns, and Apricot Hill’s sharp elevation changes will throw off any car with loose springs or stiff dampers. To ensure the car is well-prepared, I suggest driving the car on at least two of these tracks.

Personally I like to start with the ride height, dampers and LSD. From basic testing, I can usually tell whether I need to induce oversteer or understeer, and the dampers can act as a base setting. For powerful FR’s, I know I want the centre of gravity to be towards the rear for extra traction, so I try to find the right front ride height bias that gives the best handling.

Setting the LSD early lets me tune the suspension more aggressively later on. For many high-powered FR’s, I’ll set the Initial and Acceleration to 60 / 60 straight away to reduce corner exit wheelspin.

Tuning is an iterative process, and you’ll likely need to revisit settings constantly as one change can affect another. This is especially true for spring rates and camber. Keep in mind that it’s impossible to have the ‘perfect settings’, as a car can drive well on one track but have problems on another.

Remember that driving your car in Test and Setting will increase your car’s mileage. If you care about engine wear, save before doing any tests, write down your settings when you’re done, then load the save and tune the car with these settings.

Suspension

Spring rate

Front: its value will depend on the tyres equipped (softer tyres --> stiffer springs), the amount of downforce the car has, the car's drivetrain, and how powerful it is (powerful engine --> stiffer springs).
Rear: its value will be relative to the front (stiffer/softer rear --> oversteer/understeer).

If the front springs are too soft and the rear springs are too stiff, the car will lose stability when entering corners. Meanwhile, if the front is too stiff and the rear is too soft, the car will have trouble to turn around corners.

Ride height [WIP]

has, the car's drivetrain, and how powerful it is (powerful engine --> stiffer springs).
Rear: its value will be relative to the front (stiffer/softer rear --> oversteer/understeer).

Adjusting the ride height allows you to move around the car’s centre of gravity; a lower ride height reduces the effects of weight transfer and increases stability on flat surfaces.

There are no major performance drawbacks to a low ride height, as Gran Turismo 3 does not simulate ‘bottoming out’. However, increasing the ride height can also help the car’s ability to absorb bumps while reducing unpredictability during sudden elevation changes. This is useful for bumpy tracks or rally. Some cars get disturbed easily by curbs and bumps, and need a higher height.

Some powerful cars will constantly produce sparks with a low ride height. This is purely cosmetic and doesn’t slow the car down, though it makes it more difficult to see properly when driving in chase cam.

The front-rear bias will affect the car’s horizontal centre of gravity. A low front and a high rear moves the centre forward, increasing stability while also making the car much more difficult to turn. A high front and a low rear moves it back, making the car easier to turn but also more likely to drift or spin out.

However, a ride height bias can affect traction, resulting in a change of acceleration. For example, setting a high front height on a powerful RWD will move the centre of gravity closer to the rear wheels, putting more weight onto them and reducing wheelspin. Doing the same on an FF will put less weight on the front wheels, increasing wheelspin.

Dampers/Shocks

Issue	Place	Solution
Understeer	Corner entry	Soft front bound and stiff rear rebound
Oversteer	Corner entry	Stiff front bound and soft rear rebound
Understeer	Corner exit	Soft rear bound and stiff front rebound
Oversteer	Corner exit	Stiff rear bound and soft front rebound

Camber angle

The camber angle helps the car grip better in corners, at the cost of losing traction in straights and uneven tyre wear. It is important to not set up extreme values, since higher tyre wear will be added to the list of consequences of modifying the camber angle.

So in general, you want to have at least 0.5 of camber, but not more than 4.5, because at that point the car's braking distances will be noticeably worse.

Toe angle

Issue	Solution	Negative consequences
Lack of stability in straight lines and in corner exits	Positive toe angle	Worse turning ability
Bad turning ability	Negative toe angle	Worse stability in straight lines and in corner exits

Something worth noting, is that rear toe has a bigger impact on the car than front toe. Regardless of that, if you set up some toe-in or toe-out, the tyre will suffer from some higher wear than without any, so if possible try to remedy the issues discussed below by adjusting the car's height.

Stabilisers

Highest value	Impact
Front	Stability
Rear	Turning response

Brakes

Brakes balance

Drivetrain	Highest value
RWD	Front
FF	Rear
4WD	Rear

Drivetrain

Limited-slip differential initial [WIP]

Front: its value will depend on the tyres equipped (softer tyres --> stiffer springs), the amount of downforce the car has, the car's drivetrain, and how powerful it is (powerful engine --> stiffer springs).
Rear: its value will

The Initial value determines the general severity of the effect. If you wanted the LSD to activate fully during acceleration, for example, set this and LSD Acceleration to 60. Otherwise, keep this at a balanced value, depending on what Acceleration and Decrease are set to.

Limited-slip differential acceleration [WIP]

Front: its value will depend on the tyres equipped (softer tyres --> stiffer springs), the amount of downforce the car has, the car's drivetrain, and how powerful it is (powerful engine --> stiffer springs).
Rear: its value will

The Acceleration value determines the effect while the car is accelerating. If the car experiences power oversteer, raise this value. If the car is difficult to turn while accelerating out of corners, decrease this value.

Limited-slip differential decrease

Issue	Solution
Dive-bombing into corners	Higher value
Difficult to turn at corner entries	Lower value

Remember to set its value alongside the brake balance, since both things are able to fix stability issues while braking.

Gear ratio

Step #1: move the final gear to the right (or to the required value where this setup doesn't hamper the car's acceleration)
Step #2: move the auto setting slider to the right, then back left
Step #3: move the final gear to the left until the point before any of the gears disappears completely from the chart
Step #4: move the 1st gear to the left
Step #5: move the 4th and 5th gears to the right
Step #6: position the 3rd and 2nd gears so the transitions between each gear is as smooth as possible
Step #7: position the 6th gear
Step #8: move the final gear to the left if that wasn't possible during step number 3

Others

Downforce [WIP]

Front: its value will depend on the tyres equipped (softer tyres --> stiffer springs), the amount of downforce the car has, the car's drivetrain, and how powerful it is (powerful engine --> stiffer springs).
Rear: its value will

In almost all circumstances, you want to set the front and rear downforce all the way to the right. While the car will be slightly less fast on long straights, the extra cornering grip will more than make up for it. You can also tune the suspension more aggressively for extra turning ability, as the car will be less likely to lose grip and spin out.

The main exception is Test Course. Downforce serves no purpose here, and actually harms the car’s acceleration. Therefore, always set downforce to minimum on both front and rear before entering Test Course races. Remember to set it back to max after the race, however, as your car will have terrible handling with low downforce.

Some street cars allow you to adjust downforce only for the rear. This is less useful than being able to adjust both the front and rear, especially on 4WD’s. Too much downforce on the rear may impact the car’s ability to turn into corners.

I suggest setting it to at least 1.5 times the value of front downforce (eg. if front is 0.18, set rear to 0.27). For RWD’s, setting it higher can allow you to stiffen the rear springs and damper rebound values for extra turning ability.

AYC controller

This component does not seem to do barely anything good. In fact, a high setting makes the car's handling more unpredictable as it can randomly begin to understeer mid-corner.

ASM

Set it to 0, as it this assist does nothing but prevent you from actually driving properly and just bruteforce your way to victory without any kind of effort into your playthrough.

TCS

Type of input	TCS value
Analog acceleration	0
Digital acceleration	1
Digital steering	2-3

VCD controller

Setting it to 10% it will make any 4WD car turn like a RWD one. Increasing its value is not necessary unless the car needs extra stability.