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

If you use a slower auto setting when applying the gear trick, the gears will be longer, but less close. This is rarely useful, as sacrificing close gears is detrimental for many cars. It can, however, be used on 4WD’s with wide power bands that need extra top speed.

The gear trick by itself is not always foolproof. In some cars, the length and position of 4th, 5th and 6th gear can greatly impact your car’s acceleration. This is most noticeable in high-downforce F1 cars; if you use a max final gear when applying the gear trick to the F094/S or Polyphony001, when you gear up from 4th to 5th, the car’s acceleration will suddenly be crippled.

To combat this, you will need to re-do the gear trick with a different final gear until 4th and 5th receive enough torque to properly accelerate the car at high speeds. This may take some trial and error, and I suggest testing the car’s gears at a machine test.

Bring the car to a race, a machine test or a run & setting from the garage
Go to Setting -> Settings -> page 3 -> Gear Ratio
Move the final gear to the right by holding R1 (if a tune specifies a specific gear value to use, bring it to that value, otherwise bring it all the way to the right)
Move the auto setting slider all the way to the right, then back left, to the lowest setting (don’t move the slider after this, or the gears will reset and you’ll have to start over)
Move the final gear all the way to the left by holding L1 (if 5th and/or 6th gear disappear in the chart, stop and go back to the right until they’re visible, continue with steps 6 - 8, then move the slider back to the left again)
Move 1st gear all the way to the left, and 4th and 5th gear all the way to the right
Position 3rd and 2nd gear so the slopes and the start points of each gear ascend smoothly from the previous gear to the next
Position 6th gear
Press ‘OK’ to save changes

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.

If your car is trailing directly behind another car on a straight, the amount of air the car travels through will be reduced. This results in less wind resistance pushing the car backwards, along with less downforce being produced. The car is therefore able to accelerate much more efficiently. This is known as slipstreaming, or drafting. While slipstreaming, the sound of wind hitting the car will disappear.

Slipstream can be a blessing or a curse depending on the situation. On Test Course and many tracks with long straights, it’s a positive effect, as it will give a big acceleration boost and allow you to catch up to the car you’re drafting. The boost in acceleration will be most noticeable on cars with high downforce.

However, if you continue to slipstream while approaching a corner, the car will lack downforce. This will greatly affect the car’s braking distances and grip while entering the corner. To counter this, you need to make sure you stop slipstreaming well in advance, ideally taking an inside line so you can attempt an overtake.

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 [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

Every car you buy or win will automatically have ASM set to 10 and TCS set to 5. You’ll need to go into the car settings immediately before racing to adjust these. When ASM and/or TCS are turned on, they will be lit up underneath the speedometer in the HUD. When they’re in effect, the lights will blink on and off.

ASM prevents the car from losing stability while cornering, with the value controlling the severity of the effect. It will come into effect when the wheels lose grip, and it will slow down and straighten the car to restore stability.

ASM usually does more harm than good as it makes the car much more difficult to corner with. A slight loss of grip often allows a car to turn into a corner, but ASM just gets in the way and limits the car’s speed and turning ability.

TCS throttles the car’s acceleration in order to prevent wheelspin. This is most noticeable when the car launches, when it exits slow corners or when it goes off-road. With higher values, TCS will activate even when the car is making slight turns. TCS can also help with stability when exiting slow corners by preventing excessive power oversteer.

TCS is much more useful than ASM, as you often want to prevent wheelspin to reduce tyre wear. However, the default setting of 5 is way too much for most cars, especially if you’re using analog steering and/or acceleration controls.

A car with a good gear setup will launch faster with 0 TCS, even with wheelspin. The car will be right in the power band once it regains grip, while with TCS of 1 or higher, it takes some time to crawl up. If the TCS light blinks while the car is in 2nd gear and above, it’s a sign that your gears are too short and you’re losing acceleration, as TCS keeps detecting wheelspin.

If you’re driving in manual, you can already replicate most of what TCS is doing. You can launch the car in 2nd gear to reduce wheelspin, and you can keep the car in a higher gear when exiting corners so the car has lower acceleration and isn’t as prone to power oversteer. This makes a low TCS setting much more reasonable.

If you’re using precise analog acceleration controls (eg. foot pedals or analog sticks), you may drive faster by setting TCS to 0. As you have much more control over the car’s acceleration, you can ease off the throttle manually to prevent wheelspin.

If you’re using digital acceleration controls (eg. the X button), I suggest a value of at least 1 for most cars. While the car will be slightly slower, you won’t have to worry about carefully managing the car’s acceleration. Set it higher if you’re using digital steering controls; a value of 2 or 3 should offset the twitchiness caused by using left/right buttons to steer the car.

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

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.