Car Setups and Pitstop

Car Setup

Multiple preset setups are available from the moment you start a session.

When loading into a session, you will have a choice of preset setups you can load. By default, the "safe" preset is loaded and can be edited immediately.

1. Safe - A stable base setup. Recommended for finding a car that suits your driving style, but is more likely to understeer than other presets.
2. Aggressive - A more aggressive setup aimed towards drivers who are comfortable in a specific car. More oriented towards oversteer, and requires more precision in driving style (such as awareness of a car's individual nuances and general behaviour).
3. Wet - A setup that caters to wet conditions, providing more rear downforce as well as optimisations to braking and stability. Not recommended for dry conditions.
4. Current - Edit the currently loaded setup (by default, the Safe preset).

Tyres

Tire Pressures

Tyre pressures are one of the most vital components of a setup, and can make a big difference to tyre life and lap times. ACC uses pounds per square inch (psi) to measure tyre pressures. Real-time pressure values ??are displayed in the tire app. A visual representation of tyre inflation is given by the height of the middle segment of a given tyre.

• If the centre segment of a tyre is shorter than the other two segments, the tyre is underinflated.
• If the centre segment of a tyre is longer than the other two segments, the tyre is overinflated.
  • Both of these scenarios will result in loss of overall grip.

A good strategy for tuning tyre pressures is to drive 5-10 laps, and watch the tire pressures at the end of the longest straight (usually at the start/finish line). These laps do not necessarily need to be fast, but should be consistent and repeatable. Remember the following when changing pressure settings:

• Default setups, and thus default starting tyre pressures, usually return lower-than-optimum tyre pressure values after the tyres have warmed. Increasing the values in the tire setup menu may help to compensate for this.
• The optimum tyre pressure range for Group GT3 cars is between 27.3 and 27.9 psi (with Pirelli's DHE compound, as used on 2020 tracks).
  • On 2018-2019 tracks, the optimum pressure range is between 27.0 and 28.0 psi (with Pirelli's DHD2 compound tyre, as used on 2018-19 tracks.).
    • This compound has better grip outside the optimal temperature range, but less grip within it, and is more prone to temperature change under load.
• The optimum tyre pressure range for Group GT4 cars is between 26.8 and 27.4 PSI are optimal (with Pirelli's DHA compound tyre).
• For all car classes, wet tyre pressures between 30.0 and 31.0 PSI are optimal (with Pirelli's WH compound tyre).
• To adjust for changing track temperatures, remember the following ratio: .08 psi for every 1C air temperature change. When the temperature increases, decrease the pressure, and vice versa.

Tire Temperatures

The tire app also gives a visual representation of the the three temperature "zones" (O-M-I or I-M-O).

Temperature is denoted by the colour of each tyre segment. The colour range is as follows:

Numerical temperature values can be found either in the cockpit display (depending on vehicle) or in the setup menu.

Tyre temperature and tyre pressure are intrinsically linked - as tyre heat increases, tyre pressure will slowly build up. This is why it's important to take pressure measurements after a few laps, when the tyre has had time to heat up to its optimum temperature - setting the wrong starting pressure will result in the tyre being wrongly inflated when it's up to temperature. Here are a few key points on tyre temperature:

• The optimum temperature for tyres in ACC is around 85 °C, although the tyres have a working range of around 10 °C either side of this, and will still be good to use within this range.
  • Tyres that are too cold will be prone to graining if pushed too hard. Graining is a specific wear pattern where the tyre tread does not fully separate as the tyre wears down - resulting in small grains of rubber sticking to the tyre and reducing the effective contact patch.
    • Graining is often a short-term issue, experienced in the earlier parts of a stint, and can often resolve itself as the tyre heats up and begins to wear normally - but can contribute to faster tyre grip fall-off.
  • Tyres that are too hot will be prone to blistering if pushed too hard. Blistering is, in effect, the opposite to graining, where the tyre compound itself begins to degrade due to excess heat - resulting in small chunks of the tread lifting, and ultimately breaking away - reducing the effective contact patch.
    • Blistering often occurs near the end of a stint, and is considered to be far more serious than graining due to the potential of complete tyre failure if left unchecked.

Tyre graining, where the tread sticks to itself in small grains.

Tyre blistering, where the tread rises and ultimately peels off.

Setup Menu Parameters

Tyre pressure and temperature are one of the most important parts of a setup.

Property	Example Values	Description
Last Readings		Last recorded tyre temperature for this particular wheel. Note that this may not be representative of tyre temperature over an entire stint.
O M I / I M O	87 91 93	Temperature (°C) of the tyre segments: (O)utside / (M)iddle / (I)nside or (I)nside / (M)iddle / (O)utside (depending on side of car).
psi hot	27.3	Highest recorded tyre pressure (psi) at any point during the previous run.
wear	2.95 2.93 2.91	Remaining tyre tread of the tyre segments (O/M/I or I/M/O). 3.0mm is the amount of tread on a new tyre. At 1.5mm remaining the tyre is considered worn and should be changed.
Tyres		Setup adjustments for wheels. All adjustments are asymmetric, ie. values changed on one side of the car are not automatically changed on the other.
psi	25.2 psi	Starting pressure of the tyre. For Group GT3 cars, this is the "warm" pressure (tyre warmers keep the tyre at around 70 °C). For Group GT4, which doesn't allow tyre warmers, this is the "cold" pressure (the tyre will start at around 30 °C).
toe	0.2°	This is the angle offset of the wheel relative to the direction of travel. More information: https://en.wikipedia.org/wiki/Toe_(automotive)
camber	-4.1°	This is the vertical angle of the wheel relative to the roadway. More information: https://en.wikipedia.org/wiki/Camber_angle
caster	-10.6°	This is the vertical angle of the rotational axis of the steering hub on the front wheels. More information: https://en.wikipedia.org/wiki/Caster_angle

Electronics

Current Setup / TAB Eletronics

ECU Mapping

Setup Menu Parameters

Property	Values	Description
TC(1)	0 - ?	Primary traction control setting. Lower values indicate less TCS intervention. In cars with 2-stage traction control, the TC1 setting dictates the limit of wheel slip permitted before intervention occurs.
ABS	0 - ?	Anti-lock braking system setting. Lower values indicate less ABS intervention.
ECU Map		Engine control unit mapping. Defines the amount of fuel sent to the engine, as well as throttle maps and engine braking. ECU Maps
telemetry laps	0 - 99	This sets the number of laps to be recorded to the MoTeC datalogging file. MoTeC must be installed beforehand!
TC2	0 - ?	Secondary traction control setting. Only available on cars with 2-stage traction control. The TC2 setting dictates the strength of the TCS system response when wheel slip, as governed by the TC1, is detected.

Fuel and Strategy

Current Setup / TAB Fuel and Strategy

Setup Menu Parameters

Property	Values	Description
Wear	3.00 to 0.00	Amount of tyre tread remaining in millimetres. At 3mm, the tyre is new. At 1.5mm, the tyre is considered worn and it is recommended to replace it.
Grain	None to Heavy	Graining is a specific pattern of tyre wear that occurs when the tyre withstands large amounts of scrubbing or sliding, usually from understeering.
Blister	None to Heavy	Blistering is when the layers of rubber that make up the tyre start to separate from each other. Usually caused by having very high heat levels.
Flat Spot	None to Heavy	Flat spotting occurs when the tyre locks up under braking,` and a specific section of the tyre receives much more wear than the rest. This causes an unpleasant juddering in the wheel, and can cause punctures in extreme circumstances.
pad wear	29.00 to 0.00	The amount that the brake pads have worn in millimetres. At 12.5mm, the brakes are considered worn and it is recommended to replace them.
disc wear	31.00 to 0.00	The amount that the brake discs have worn in millimetres. Usually, a set of discs will make a 24 hour race, but new discs are always fitted when brake pads are changed with no additional time penalty.
Fuel and Tyre
fuel	1 - ?	The amount of fuel in the fuel tank upon exiting the pits/going to track. Maximum fuel load varies per car.
tyre	Dry or Wet	Choose the type of tyre depending on prevailing track conditions.
tyre set [1]	1 - ?	This allows you to change your currently installed tyre set. The sets are limited as follows: Sprint race weekend: 5 sets 3-hour Endurance race weekend: 6 sets 6-hour Endurance race weekend: 9 sets 24-hour Endurance race weekend: no limit. There is also no limit for wet tyre sets.
front brakes	1 - 4	Choose the ?Brake Pads on the front axle.
rear brakes	1 - 4	Choose the ?Brake Pads on the rear axle.
fuel per lap		Average fuel consumption per lap. Automatically calculated.
Pitstop Strategy
N°.
fuel to add
tyre
tyre set
left front
right front
left rear
right rear
front brakes	1 - 4	Choose the ?Brake Pads on the front axle.
rear brakes	1 - 4	Choose the ?Brake Pads on the rear axle.

Brake pads

Value	Description
1	"Sprint" brake pads. Excellent friction coefficient with maximum braking performance but rather severe disc and pad wear. Performance with brake modulation is somewhat linear. Perfect for short (1-3) hour races and qualifying sessions. It is best not to use these pads beyond 2 hours of racing as they will quickly start to overheat and lose linearity in brake pedal feel when worn out, making braking consistently a lot harder, and the pads may wear out before the 3 hour distance is reached.
2	"Endurance" brake pads. Very good friction coefficient with great braking performance and moderate disc and pad wear. Performance with brake modulation is very linear. Perfect for long (3+ hours) endurance races, but can also be used in shorter races and qualifying/hotlap sessions. What it loses in outright performance, it gains in braking predictability and a more consistent feeling. It is the default choice for long endurance races, as it easily lasts 12 hours' distance, and with a bit of care will make a full 24 hour race. It will still overheat and lose linearity in brake pedal feel when worn out, but in a more predictable way than brake pads 1, and after much longer stints. Because of the lower friction, you could possibly use smaller brake ducts, which will help keep tyre temperatures and pressures more consistent.
3	"Rain" brake pads. Good friction coefficient with good braking performance and low disc and pad wear. Performance with brake modulation is almost always linear. Will easily make a 24 hour race without issues. The lower friction coefficient means that braking distances in optimal conditions will be longer than with pads 1 or 2, but these pads are an excellent choice for wet weather conditions where more care is needed when braking. These pads rarely have issues with overheating when worn.
4	"Superpole" brake pads. These pads are functionally useless. They have a very similar friction coefficient to brake pads 1, however they suffer from extreme disc and pad wear and it is very hard to get a linear response from these pads - as they wear down and overheat very quickly, usually within 15 minutes. These pads should almost never be used and do not exist in the world of endurance racing - they are only included for demonstration purposes.

Mechanical Grip

Current Setup / TAB Mechanical Grip

Property	Values	Description
Front
antiroll bar
brake power
brake bias
steer ratio
Rear
antiroll bar
preload differential
Rear/Front - Left/Right
wheel rate
bumpstop rate
bumpstop range

Dampers

Current Setup / TAB Dampers

Property	Values	Description
Rear/Front - Left/Right
bump		stops the springs oscillation inward. A higher number wil dampen the compression at a slow rate more.
fast bump		A higher number wil dampen the compression at a high rate more.
rebound		stops the springs oscillation outward. A higher number wil dampen the decompression at a slow rate more.
fast rebound		A higher number wil dampen the decompression at a high rate more.

Aero

Current Setup / TAB Aero

Property	Values	Description
Rear
rear ride height		Higher values offer stability over kerbs but reduce rear diffuser downforce.
rear wing	0 - ?	Higher values increase drag but increase rear downforce.
brake ducts	0 - 6	How much cooling the brake discs receive. 0 is fully closed, 6 is fully open. Affects aerodynamics and tyre temperatures somewhat.
Front
front ride height		Higher values offer stability over kerbs but reduce front splitter downforce.
splitter	0 - ?	Higher values increase drag slightly but provide front downforce. Only adjustable on some cars.
brake ducts	0 - 6	How much cooling the brake discs receive. 0 is fully closed, 6 is fully open. Affects aerodynamics and tyre temperatures somewhat.
Fuel Load Test
temporary fuel	0 litre - ? litre	Simulates the weight of the contents of the tank and the impact on the aero model of the car. Depending on where the tank is located in a car, it has different effects. This setting can only be used in Practice sessions.
Front Aero Variation
Base ride height	xx rear - xx front x.x%	Percent of aerodynamic force bias towards the front of the car. Negative values indicate rearward aero bias.

Race Start Procedure

In ACC, a server administrator can specify three different methods for starting on a server (→ Server Configuration/settings.json) and whether a short or a complete Formation-Lap should take place.

Controlled Start with Position Widget

Each driver is guided through the start of the race by a widget. The driver must always try to stay in the green area. First is the single file at 90 km/h (if doing a full formation lap), then the double file at 60 km/h.

• You can press "Drive" 30 seconds before the end of the countdown. Don't forget to fill up on fuel, or change to your race setup.
• You can now start your vehicle, but not change the gear or move.
• Once the timer hits 0, a "Rolling Start Procedure" warning is given.
• The pole-sitter starts first and all other vehicles are now unlocked one after the other and drivers can then engage 1st gear and drive off. Note: Collisions not are possible, cars can drive through each other.
• A widget is now displayed for every driver and you are asked to...
  • Drive in double file if not doing a full formation lap.
  • Start in single file, then slow down and change to double file, usually before the last corner.
• By always being on the green coloured scale of the widget, you are always in the right starting position.
• Shortly before the start, the widget will switch to a speed monitoring mode. Try to keep the speed in the green.
• Soon after the leader crosses the start-finish line, five flashing green lights will appear, and the race starts!
• Drive-through penalties are awarded for driving too fast and not adhering to the starting position.

Old Mode

• You can press "Drive" 30 seconds before the end of the countdown. Don't forget to fill up on fuel, or change to your race setup.
• You can now start your vehicle, but not change the gear or move.
• Once the timer hits 0, everyone can drive off. Note: collisions are possible, so don't try to drive through other cars.
• The vehicle's speeds are locked at around 90km/h
• There is no positional control, cars are free to be in whatever position possible. As such, no penalties are awarded automatically.

Free Mode

At the start of the race, only the traffic lights are shown. This is usually only used by leagues that have their own race control.

Pitstop

A pit stop to refuel missing gas or repair damage is possible in practice, qualifying and racing. A driver can set his pit stop strategy in the vehicle setup (Fuel and Strategy) and change it while driving in the multifunction display (MFD). In a race without a compulsory pit stop, the pit lane is opened when the leader of the race has finished the first lap. In the middle of the lower part of the screen, the message of the race control is displayed: RCTL Pitlane is open

Server Configuration, see here: →eventRules.json

Mandatory Pitstop

• Variant 1: mandatory Pitstop possible throughout the race.
• Variant 2: mandatory Pitstop Window is limited in time. (Pitstop for damage repair always possible)
• Example: Race: 18 min / Window: 6min = from 6. Minute to 12. Minute
  
• What can be required for a mandatory pit stop?
  • refueling
  • change wheels
  • driver swap

Server Configuration, see here: →eventRules.json

Driver Swap

(in MP: Swapping the riders works, but the operation is not intuitive and faulty! Last time tested: 17.11.2019 ACCv1.1.2)

Pit / Driver Swap

Several drivers (in Blancpain real: 2-4) can form a team. All drivers can be on the server. The waiting drivers are not considered spectators in the sense of →Spectator Mode.

Using the Pit strategy page in the ( M )ulti(F )unctional( D )isplay (key: insert), the driver can assign a driver swap which will be automatically executed during the next pitstop.

In a training or qualification session, drivers of a team can use the chat command to swap drivers while the car is in the pit lane. Simply use the chat command and enter the space in the team widget. For example in "& swap 1" the driver changes to the driver who comes first. The waiting driver must be on the server.

Server Configuration, see here: →eventRules.json and →entylist.json

References

1. Suspension and Spart... setups, I mean setups! - Kunos Forum - ACC Blog von Aristotelis
2. ECU maps implementation - Kunos Forum - ACC Blog von Aristotelis
3. Brake ducts and Tyre damage - Kunos Forum - ACC Blog von Aristotelis
4. Bumpstop telemetry in the setup screen - Kunos Forum - ACC Blog von Aristotelis
5. https://en.wikipedia.org/wiki/Caster_angle
6. https://en.wikipedia.org/wiki/Camber_angle
7. MSRL - Midnight Sim Racing Liga - YouTube Playlist: MSRL SetupGuide (German):