Every car mod contains a data folder full of .ini files, each of which controls one aspect of the vehicle's behavior. The top-level car.ini defines global properties: TOTALMASS (the chassis mass without fuel and driver), INERTIA as a three-component vector for resistance around the pitch, yaw, and roll axes, CG_LOCATION for the center of gravity in three coordinates, MIN_RPM and MAX_RPM for the engine's operating range, GRAPHICS_OFFSET for aligning the visual model with the physics center, ffb_mult for tuning force feedback strength, and SLIPSTREAM_DRAFT and SLIPSTREAM_DISTANCE for the draft effect. The engine behavior lives in engine.ini, which references a power.lut lookup table defining how torque varies with RPM (the HEADER_CURVE) and includes parameters such as LIMITER (the redline), IDLE_RPM, INERTIA (the crankshaft's rotational inertia, which affects throttle response), FUEL_CONSUMPTION, MAX_BOOST for turbocharged cars, coast_torque for engine braking, and DAMAGE_GAIN for over-rev or overheat penalties. Supplementary files such as ctrl_turbo.ini, ctrl_ers.ini, kers.ini, and fuel_cons.ini handle boost controllers, hybrid energy recovery systems, KERS batteries, and fuel usage curves respectively.
The tyres.ini file governs the thermal and grip model for each tire compound, with parameters such as RADIUS, RIM_RADIUS, FZ0 (the reference vertical load), OPTIMAL_TEMP (the core temperature where grip peaks), PRESSURE_STATIC (the cold starting pressure), PRESSURE_GAIN and TEMPERATURE_GAIN for how pressure and temperature respond to use, DAMPING for vertical compliance, WEAR_CURVE (a LUT defining how grip falls off with wear), and GRAIN_GAMMA and BLISTER_GAMMA for the rates at which surface graining and blistering develop. The suspensions.ini file defines geometry and stiffness for each wheel, including TYPE values such as DW (double wishbone) and STRUT (MacPherson strut), RIDE_HEIGHT, SPRING_RATE, DAMPER_BUMP and DAMPER_REBOUND for compression and extension damping, ARB_ANTIROLL for anti-roll bar stiffness, CAMBER (negative for top-tilted-inward), CASTER for steering axis tilt, ACKERMANN for steering geometry, TOE_OUT for static toe alignment, and CAMBER_GAIN for how camber changes through the suspension travel.
Drivetrain, braking, electronics, and aero behavior are spread across several other files. drivetrain.ini contains GEAR_RATIO entries per gear, FINAL_RATIO, GEAR_EFFICIENCY for transmission losses, the [DIFFERENTIAL] section's POWER and COAST values for accel and decel locking percentages, and an AWD indicator for all-wheel-drive cars. brakes.ini defines MAX_TORQUE, BRAKE_BIAS (0.0 = full rear, 1.0 = full front), and COOLING_RATE. electronics.ini houses ABS, TC, ESP, and AUTO_SHIFTER settings. aero.ini describes CL (coefficient of lift, negative for downforce), CD (coefficient of drag), AREA (reference frontal area), and gain terms CL_GAIN and CD_GAIN that describe how adjustable wings affect lift and drag as a function of WING_ANGLE. For active aerodynamics, wing_animations.ini drives mesh-based movement with triggers like speed or brake input, while wing_controller.ini automates wing angle from inputs such as speed, brake pressure, or steering angle via a CURVE lookup table. Additional files such as damage.ini, setup.ini (the pit-menu setup options), colliders.ini, flames.ini, lights.ini, mirrors.ini, driver3d.ini, analog_instruments.ini, digital_instruments.ini, ambient_shadows.ini, blurred_objects.ini, lods.ini, models.ini, extra_animations.ini, pitcrew.ini, and neck.ini round out the rest of the car's editable behavior, covering everything from visible deformation to analog gauge needle rotations and driver head movement under G-forces.