The setup handbook — why a change works, not what to copy

THE SETUP HANDBOOK

Every chapter of the handbook that ships inside the program, word for word. It is written for somebody who wants to know why a change works, not a list of numbers to copy.

1. Philosophy of Speed

1. THE PHILOSOPHY OF SPEED (BEYOND BASICS)

THE 333HZ REALITY

Assetto Corsa is not a game. It is a physics integrator running at 333Hz. Every 3 milliseconds, the engine calculates the load on each tyre node.

To go fast, you must stop driving 'visually' and start driving 'mathematically'. You are managing 4 contact patches of rubber, each the size of a credit card.

THE FRICTION CIRCLE (GG DIAGRAM)

^ Braking (1.5G)

|

Left <+> Right (Turning)

|

v Accel

Most drivers treat inputs as binary switches. Pros treat them as a blend.

If you are Braking at 100%, you have 0% Grip left for Turning. To turn, you MUST release the brake. This blending is where 90% of lap time is found.

2. Advanced Braking Physics

2. ADVANCED BRAKING PHYSICS & TRAIL BRAKING

THE 'SHARK FIN' TRACE

100% |   |\     <-- Instant Attack

|   | \    <-- Modulation Phase

|   |  \   <-- Trail Braking into Apex

0% |___|___\_______

WHY THE RECTANGLE IS SLOW

100% |   |---|  <-- Holding max pressure too long

|   |   |  <-- Sudden release

0% |___|___|_______

Sudden release causes the front suspension to spring up (Rebound). This unloads the front tyres instantly.

Result: Understeer. The car refuses to turn because you removed the weight from the front wheels.

Smooth release = Compressed springs = Turned in car.

3. Traction & Differentials

3. TRACTION, DIFFERENTIALS & YAW

DIFFERENTIAL TUNING (THE DARK ART)

The Diff controls how the rear wheels rotate relative to each other.

POWER LOCK (ACCELERATION)

High Lock %: Wheels spin at same speed. Great traction, but pushes the nose wide (Understeer on exit).

Low Lock %: Wheels spin independently. Car rotates easily, but inside wheel spins (One-tyre fire).

COAST LOCK (BRAKING/ENTRY)

This is your 'Stability Control'.

[High Coast Lock] -> Car wants to go straight. Stable braking.

[Low Coast Lock]  -> Car rotates eagerly. Risk of spin on entry.

If you spin entering a corner: Increase Coast Lock or Preload.

If you can't hit the apex: Decrease Coast Lock.

4. Aero: Centers of Pressure

4. AERODYNAMICS: CENTER OF PRESSURE (CoP)

THE AERO SEESAW

Think of your car as a seesaw balanced on the CoP.

Front Wing       CoP        Rear Wing

|_____________A_____________|

^

RAKE ANGLE (THE SECRET WEAPON)

Rake is the angle of the floor. Rear Height - Front Height.

/---\

__/__|__\__   <-- High Rake (Nose Down)

(O)_______(O)

Increasing Rake (lifting the rear) shifts Aero Balance FORWARD. This cures high-speed understeer without adding front wing drag.

Too much Rake? The diffuser stalls (airflow detaches). You lose ALL rear grip instantly.

5. Tyre Molecular Dynamics

5. TYRE THERMODYNAMICS & HYSTERESIS

MOLECULAR FRICTION

Tyres don't just 'rub'. The rubber deforms into the asphalt pores. This deformation generates heat (Hysteresis).

THE I/M/O MATRIX

We monitor 3 zones: Inner, Middle, Outer.

Inside | Middle | Outside

95°C  |  90°C  |  82°C   <-- Ideal Pattern

Why is Inside hotter? Because of Negative Camber. We drive on the inside edge to prepare for the corner roll.

If Middle > Inside: Over-inflation (Ballooning). Reduce Pressure.

If Outside > Inside: Positive Camber problem. You are rolling over the tyre. Increase Negative Camber immediately.

6. Suspension: Frequencies

6. SUSPENSION: FREQUENCIES & MOTION RATIO

NATURAL FREQUENCY (HZ)

Suspension stiffness is best measured in Hz, not N/mm.

GT3 Target: 2.5Hz Front / 3.0Hz Rear.

THE MOTION RATIO TRAP

Real cars have leverage. A 200 N/mm spring on the car might only be 150 N/mm at the wheel.

Wheel_Rate = Spring_Rate * (Motion_Ratio)^2

Stiff Front Springs = Stable Aero Platform but Understeer.

Soft Rear Springs = Great Traction but unstable Diffuser height.

7. Dampers: Histograms

7. DAMPERS: HISTOGRAMS & PACKERS

BUMP VS REBOUND

Bump: Controls how fast the wheel moves UP (hitting a bump).

Rebound: Controls how fast the wheel moves DOWN (returning to track).

PACKERS (BUMP STOPS)

These are rubber pucks that stop the suspension travel physically.

[ Chassis ]

|

[===] <-- Packer (Gap Limiter)

(Spring)

Use Packers to stop the car from scraping the floor at high speed, while keeping soft springs for slow corners. This is the 'Third Spring' trick.

8. FFB: Pneumatic Trail

8. FFB: PNEUMATIC TRAIL & SELF ALIGNMENT

WHY STEERING GOES LIGHT

Force Feedback is generated by 'Pneumatic Trail' - the distance between the tyre's contact patch center and the actual grip forces.

Grip Force |      /--\

|     /    \

|____/______\___

Slip Angle |   6°   10°

At peak grip (6°), force is highest. Beyond the limit (10°+), pneumatic trail collapses. The steering goes light.

If the wheel goes light mid-corner, DO NOT turn more. You are understeering. Straighten the wheel slightly to regain grip.

9. Fuel Strategy Math

9. RACE STRATEGY: FUEL MATH

WEIGHT PENALTY

10L of Fuel = ~7.5kg. In a GT3 car, 10kg costs 0.1s per lap.

Starting with 100L vs 50L is a 0.5s per lap difference.

LIFT AND COAST (L&C)

The most efficient way to save fuel without losing time.

Throttle | ____

|     \

|      \_______

| Full | Coast | Brake |

Lift 100m before the braking zone. Coast. Then brake normally. Saves 0.5L per lap.

10. Ghost Data Analysis

10. GHOST DATA ANALYSIS

READING THE DELTA

Enable Ghost Mode [C] in Analysis Tab.

CASE A: THE OVERSLOW

Speed |   /--\  (Ghost)

|  /    \

| /__    \ (You)

|/   \____\

You braked too much and your mid-corner speed is 10km/h lower. Trust the aero.

CASE B: THE LATE THROTTLE

Ghost is at 100% throttle 20 meters before you. Setup issue: Rear instability or too much Diff Power Lock.

11. Setup: Car Layouts (FR/MR)

11. CAR LAYOUTS: FR vs MR vs RR

FR (FRONT ENGINE) - e.g. AMG, BMW M4

Heavy front. Engine acts as a pendulum.

Characteristics: Stable, but prone to Understeer. Tyres wear evenly.

Needs stiffer rear springs to help rotation. Use kerbs aggressively.

MR (MID ENGINE) - e.g. Ferrari 296, Audi R8

Weight is central. Low polar moment of inertia.

Characteristics: Extremely agile. Turns fast. Prone to Snap Oversteer.

Needs high Aero Rake. Smooth inputs required.

RR (REAR ENGINE) - e.g. Porsche 911

Engine is behind the rear axle.

Characteristics: Massive traction (squat). Fronts are light (Understeer entry).

Brake LATE and DEEP to keep weight on the nose. Soft rear springs for max traction.

12. Setup: Rain Engineering

12. RAIN ENGINEERING (WET SETUP)

THE GOLDEN RULES OF RAIN

Water reduces friction coefficient (mu) from 1.0 to 0.7 or less.

1. SOFTEN EVERYTHING

Disconnect Anti-Roll Bars (Set to 0 or 1). Soften Springs by 2 clicks.

Why? The car needs to lean to find grip. A stiff car will slide instantly.

2. RAISE THE CAR

Increase Ride Height by +5mm to +10mm.

Why? Prevents aquaplaning (the floor hitting the water layer).

3. MAX WING

Set Rear Wing to Maximum.

Drag doesn't matter in rain (you are slower anyway). Downforce is life.

13. Setup Troubleshooting A

13. SETUP TROUBLESHOOTING MATRIX (A)

PROBLEM: Car pushes straight (Understeer) in slow corners.

1. Soften Front Anti-Roll Bar.

2. Soften Front Springs.

3. Increase Front Camber (more negative).

PROBLEM: Car spins (Oversteer) on corner exit.

1. Soften Rear Springs.

2. Decrease Rear Ride Height.

3. Increase Traction Control (TC2).

PROBLEM: Car feels sluggish/lazy to change direction.

1. Stiffen ALL Anti-Roll Bars.

2. Increase Front Toe-Out (Negative Toe).

14. Setup Troubleshooting B

14. SETUP TROUBLESHOOTING MATRIX (B)

PROBLEM: Locking Front Wheels under braking.

1. Move Brake Bias REARWARD (-1%).

2. Stiffen Front Springs (prevent diving).

PROBLEM: Unstable Rear under braking (Dancing rear).

1. Move Brake Bias FORWARD (+1%).

2. Increase Diff Coast Lock.

PROBLEM: Bottoming out on straights (Sparks).

1. Increase Packers (Bump Stops). Do NOT just raise ride height if aero is good.

2. Stiffen Fast Bump Dampers.

15. Connection Issues

15. CONNECTION ISSUES & SHARED MEMORY

STATUS: 'WAITING FOR AC...'

This means the app cannot read the RAM map.

STEP 1: ENABLE IN CONTENT MANAGER

Go to: Settings -> Assetto Corsa -> System.

Ensure 'Shared Memory' is checked.

STEP 2: CHECK MEMORY FORMAT

Some mods change the physics format. Ensure 'Project CARS' format is UNCHECKED. We need native AC format.

STEP 3: PERMISSIONS

Try running 'ac_pro_engineer.exe' as Administrator. Windows sometimes blocks RAM access.

16. Technical Support

16. TECHNICAL SUPPORT

SETUP DOWNLOADS FAILED?

If pressing [D] does nothing:

1. Go to game -> Setup -> Save a dummy setup (e.g. 'test').

2. This forces AC to create the folder structure in 'Documents/Assetto Corsa/setups'.

3. Try downloading again.

INVALID LAPS

If telemetry is not saving: You likely cut the track. Invalid laps are discarded to prevent bad data in the Ghost system.

Watching a friend drive

WATCHING A FRIEND DRIVE

Two copies of this program on one network can show each other what they are doing. One drives; the other sees the same screens — the dashboard, the traces, the map, the corner table, the engineer — filled with the driver's session rather than its own.

ON THE MACHINE THAT WILL WATCH

Open LAN, the button at the top right. Tick "show me somebody else's session". Leave the address as it is — 0.0.0.0 means "anybody on this network" — and read out the line under it that begins "tell them to send to". That is this machine's address, and it is the only number the other person needs.

ON THE MACHINE THAT IS DRIVING

Open LAN there too. If the other machine is already listening it will be in the list under ON THIS NETWORK: press SEND TO, and that is all — the address fills itself in and sending starts. If it is not in the list, type the address they read out into the two boxes: the name or numbers in the first, the port in the second.

Put a name in "as" as well. It is what the watching screen says at the bottom — "these are Kimi's numbers" — and it is the only thing stopping somebody mistaking a friend's lap for their own.

WHAT THE WATCHER SEES

Their own tabs, with the driver's session in them. Laps are found on the watching machine, so the analysis is a real analysis — a lap that ends there gets its corner table and its engineer's debrief, and two laps can be compared as usual.

Nothing is written into their records. A friend's lap is not their personal best, and the file that outlives the session is the one place that mistake would be permanent.

When streaming does not work

WHEN STREAMING DOES NOT WORK

Both machines show a count, and between them the two numbers say which half is wrong. The driver's is in the LAN window beside the address; the watcher's is in theirs, under the address they are listening on.

THE DRIVER'S COUNT IS CLIMBING, THE WATCHER'S IS ZERO

The frames are leaving and not arriving. On Windows this is nearly always the firewall on the watching machine: the first time this program listens, Windows asks whether to allow it, and a box dismissed without reading is a link that never works. Allow it for private networks and try again.

The other cause is the wrong address. The driver must send to the watcher's own address — the one the watching machine reads out — and not to 0.0.0.0, which is what a machine listens on rather than something anybody sends to.

BOTH COUNTS ARE ZERO

Nothing is being sent. Check the mode on the driving machine: SHARE or ON AIR, and an address in the box. If "only send while the car is on track" is ticked, sitting in the menus sends nothing on purpose.

NOBODY IS IN THE LIST

Finding each other uses multicast, which some networks — most guest and hotel networks, and a few routers with it switched off — do not carry. The window says so when it cannot join. Typing the address works exactly the same; the list is a shortcut, not the feature.

IT ARRIVES, BUT IN JUMPS

The watcher's line reads frames a second, how far behind the picture is and how many were lost. Ten a second is the default and is smooth enough to watch; a number well under what the driver set, with losses climbing, is a network dropping them — on wifi, moving one of the two machines to a cable is usually the whole fix.

Writing your own screen

WRITING YOUR OWN SCREEN

Turn on RGE Studio in MODULES and a STUDIO tab appears. Its last section, SCREENS, is a document on the left and the screen it makes on the right, drawn from the car as you type. Everything below is a line of that document.

A NUMBER, A BAR, A LINE

Speed (km/h)          = speed
Throttle (%) 0..100   = throttle * 100
~ Combined g (g)      = hypot(lat_g, lon_g)

A range makes it a bar, because a bar is the thing that needs two ends. A ~ in front makes it a line over the lap. Anything else is a number read at a glance. There are no shape words to remember.

WORDS

"Doing {speed:0} km/h in gear {gear:0}."
"Fuel is low — {fuel:1} L left." when fuel < 5

A line in quotes is a sentence and {…} in it is a formula; {fuel:1} is one decimal place. Put `when` after the closing quote and the line is only there while that is true, which is how a warning is written. Only sentences take a `when`: a reading that vanished could not be told from one you deleted.

SAYING SOMETHING, AND DOING IT

Revs = if rpm > 7600 then alert "ease off" else rpm

`print`, `warn`, `alert` and `title` are things a formula does rather than works out. Only the arm of an `if` that is taken runs, so that line says one thing and not both — and the row draws itself in the colour it used, which is one thought written once. `title` renames the tab, which is the one thing you can still see with the screen closed.

REMEMBERING SOMETHING

state best = 0
remember best = max(best, speed)

A slot, and what is written into it once a frame. This is how a peak, a counter or a stopwatch is made — the things arithmetic alone cannot do. The lines run in the order they are written and wherever you are looking, so a fastest lap does not stop counting because you opened another tab.

For per lap rather than per session: `time` is seconds since the lap started, so it goes back to nought at the line. `remember this_lap = time < 1 ? speed : max(this_lap, speed)` is the whole of it.

AGAINST ANOTHER LAP

let delta = speed - best(speed)
Difference (km/h) = delta

`best(f)` is what f was at this place on the track on your quickest complete lap, and `last(f)` the same on the one you just finished. They are about where you are, not about the lap as a whole, which is what makes that line the delta every telemetry program is for. Until there is such a lap they give nothing — a nought there would read as "exactly on your best".

DRAWING

paint THE TRACK YOU ARE ON 220
path x, y in dim
here x, y, 0.025 in accent

`paint` is a panel you draw on, with `dot`, `line`, `box`, `ring`, `arc` and `text` on it, every number a formula. The space is 0 to 1 across and down and angles are degrees with 0 straight up, so a rev counter with a needle is nine lines. `path` is the exception: it fits the whole lap to the canvas by itself, which is why a map of the track is two.

WHERE IT GOES

A document with no `screen` in it draws under the editor and nowhere else. Write `screen NAME` and it becomes a tab of its own; write `instead of DASHBOARD` and it stands where one of the program's own was, which is the one thing here that takes something away and says so every time it is opened.

KEEP IT saves and lays the document out for you. BACK returns to the last version you kept. COPY MINE turns the whole thing into one line to paste to somebody, and USE IT takes theirs.

A line that does not read costs its own row and names its line number — the rest of the document still draws. Nothing you write can slow the program down: there are no loops and no way to call anything, so a formula is turned into instructions once and running it allocates nothing.