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]

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 [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

Setting the camber angle will slant the wheels horizontally to help the car grip in corners, at the potential cost of straight-line traction and uneven tyre wear.

In general, you always want at least 0.5 of camber (unless you want the wheels to intentionally lose grip in corners), but if too much is applied, the car will feel gummy and unresponsive. You can safely apply camber up until 4.5 or so; after this point, the car’s braking distances will noticeably deteriorate.

I suggest setting the camber for front and back to around 1.8 and adjusting them further once you’ve settled on your spring settings. A high rear camber can mitigate the loss of rear-wheel grip caused by stiff rear springs, for example. Try to find the right degree of camber where the car is controllable but not unresponsive.

Extreme camber values can increase tyre wear while cornering, but for most normal values, it’s not a noticeable difference.

Toe angle [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 toe angle determines whether the wheels point inwards (toe-in) or outwards (toe-out). Positive is toe-in, negative is toe-out.

Toe-in will increase the car’s stability in a straight line and when exiting corners, but will impact the car’s turning ability. Toe-out makes the car easier to turn into corners, but reduces stability when braking and exiting corners. Rear toe has more of an effect on the car than front toe.

Both toe-in and toe-out will effect tyre wear. From my experience, 1.0 of toe will make the tyres wear out 10% faster. In some cars, the benefits of toe are not worth the need to pit sooner.

A slight rear toe-in of 0.5 or 1.0 can be useful for many high-powered race cars that struggle with power oversteer when exiting corners. A high front and rear toe-out (usually -1.0 front, -2.0 rear) is useful for FF’s and 4WD’s that are already very stable and instead need extra turning ability, even if tyre wear is affected.

Most of the time though, you can avoid having to add toe by adjusting other settings. For example, a front ride height bias can make the car easier to turn, eliminating the need for toe-out. It can also improve traction in RWD’s and reduce corner exit oversteer, meaning that the car doesn’t need toe-in either.

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 [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

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

AYC controller [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

ASM [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

TCS [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

VCD controller [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 VCD controller is a 4WD-only upgrade that lets you decide the balance of torque distribution between the front and rear wheels. The greater the percentage, the more torque that’s delivered to the front wheels.

For circuit racing, setting the VCD to 10% will make the car behave more like a RWD, inducing oversteer. This can give the ‘best of both worlds’: the stability of a 4WD with the turning ability of a RWD. It also does not appear to affect the car’s tyre wear rate either. Increasing it beyond 10% is generally not necessary unless the car needs extra stability. It’s more useful in rally, as we’ll see later.

To accommodate a 10% VCD setting, you may need to buy an LSD, set the front to 5 / 5 / 5 and adjust the rear settings so the car is stable. Alongside soft front and rear springs, the car can have ridiculous turning ability.