On some tracks the cars do not have enough low end torque to leave the pits; I had to edit this for the IROC cars. Tom's Engine Shop makes this easy, slightly increase the torque just around the idle point; this will not affect performance but will get them out of the pits.
Try this file:
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// Engine File Modified by 'Tom's Engine Shop'
// 303.6 HP 5/11/2022 7:08:10 PM
// ---------------------------------------------
// Engine data generated by PhysicsEditor
RPMTORQUE=( 0.0, -12.0, -30.0)
RPMTORQUE=( 250.0, -14.6, 15.4)
RPMTORQUE=( 500.0, -17.8, 96.8)
RPMTORQUE=( 750.0, -19.9, 160.0)
RPMTORQUE=( 1000.0, -22.6, 192.2)
RPMTORQUE=( 1250.0, -25.8, 202.7)
RPMTORQUE=( 1500.0, -30.6, 211.7)
RPMTORQUE=( 1750.0, -34.9, 217.2)
RPMTORQUE=( 2000.0, -40.8, 222.4)
RPMTORQUE=( 2250.0, -47.2, 227.1)
RPMTORQUE=( 2500.0, -55.2, 230.0)
RPMTORQUE=( 2750.0, -59.0, 232.9)
RPMTORQUE=( 3000.0, -67.0, 236.3)
RPMTORQUE=( 3250.0, -73.4, 242.6)
RPMTORQUE=( 3500.0, -78.8, 246.3)
RPMTORQUE=( 3750.0, -83.6, 250.8)
RPMTORQUE=( 4000.0, -87.9, 256.7)
RPMTORQUE=( 4250.0, -91.1, 262.3)
RPMTORQUE=( 4500.0, -93.8, 268.3)
RPMTORQUE=( 4750.0, -97.5, 273.8)
RPMTORQUE=( 5000.0, -100.2, 277.1)
RPMTORQUE=( 5250.0, -102.4, 282.1)
RPMTORQUE=( 5500.0, -105.0, 285.4)
RPMTORQUE=( 5750.0, -107.7, 287.4)
RPMTORQUE=( 6000.0, -109.9, 287.8)
RPMTORQUE=( 6250.0, -112.5, 289.4)
RPMTORQUE=( 6500.0, -114.7, 289.4)
RPMTORQUE=( 6750.0, -116.3, 288.1)
RPMTORQUE=( 7000.0, -119.5, 287.1)
RPMTORQUE=( 7250.0, -120.6, 284.9)
RPMTORQUE=( 7500.0, -123.2, 280.9)
RPMTORQUE=( 7750.0, -124.3, 277.7)
RPMTORQUE=( 8000.0, -126.4, 270.3)
RPMTORQUE=( 8250.0, -127.5, 257.9)
RPMTORQUE=( 8500.0, -128.6, 241.8)
RPMTORQUE=( 8750.0, -130.7, 120.1)
RPMTORQUE=( 9000.0, -131.3, 10.0)
RPMTORQUE=( 9250.0, -132.3, 10.0)
FuelConsumption=3.600e-05 // affected by throttle position and engine speed
FuelEstimate=1.20 // fudge factor for differences between vehicle types (used for lap estimates and AI pit scheduling)
EngineInertia=0.16000 // rotational inertia of engine components
IdleThrottle=1 // throttle multiplier to help maintain idle speed
IdleRPMLogic=(1050, 1100) // attempt to maintain idle speed between these RPMs
LaunchEfficiency=0.80000 // efficiency (0.0-1.0) of launch control, or 0.0 if N/A
LaunchRPMLogic=(6000, 7500) // holds RPM in this range before launch (used for AI even if launch control is N/A!)
RevLimitRange=(8340, 100, 0.0)
RevLimitSetting=0
RevLimitLogic=15 // RPM range around current setting where rev limiter operates
RevLimitAvailable=1 // whether to use a rev limit (if 0, you still must have a "rev limit", just make it 40000 or so, and make sure to
change [CONTROLS]->UpshiftAlgorithm to fix shifting points)
EngineMapRange=(0, 1, 5) // 0 = most driveable, max = most power (low gears only) (unimplemented)
EngineMapSetting=2
EngineBrakingMapRange=(0, 1.000e-04, 2) // input throttle is ranged from minimum to 100%, with the minimum = setting * step * RPM,
EngineBrakingMapSetting=2 // the default is 1 * 0.000133 * 15000 RPM = 2% applied throttle at zero input throttle
EngineBoostRange=(0.01000, 1, 1)
EngineBoostSetting=1
BoostEffects=(15, 0.0100, 1) // RPM increase per setting, fuel increase (1%) per setting, engine wear rate (101.5%) per setting
BoostTorque=-0.00410 // 0.4% less torque per setting (applies to all RPMs)
BoostPower=1.600e-04 // % more horsepower per setting
OptimumOilTemp=95 // degrees Celsius at which engine operates optimally
CombustionHeat=40 // degrees Celsius added per liter of fuel burned
EngineSpeedHeat=0.00120 // heat added linearly with engine speed
OilMinimumCooling=0.00750 // heat dissipated without oil/water transfer
OilWaterHeatTransfer=(0.39620, 7.925e-05) // heat transfer from oil to water (base, w/ engine speed)
WaterMinimumCooling=0.00396 // heat dissipated without radiator
RadiatorCooling=(1.592e-04, 1.004e-04) // cooling rate with velocity (base, per setting)
LifetimeEngineRPM=(8300, 20) // (base engine speed for lifetime, range where lifetime is halved)
LifetimeOilTemp=(100, 3) // (base oil temp for lifetime, range where lifetime is halved)
LifetimeAvg=10800 // average lifetime in seconds
LifetimeVar=2250 // lifetime random variance
EngineEmission=(0, 0.6000, 0.7000) // where flames and smoke are emitted (relative to ref frame at rear axle)
EngineSound=(0.10000, 0.5000, 0.0) // where engine sound is played (relative to ref frame at rear axle)
SpeedLimiter=1 // whether vehicle has a pitlane speed limiter
OnboardStarter=1 // whether vehicle restarts when stalled
StarterTiming=(1.40, 0.4000, 1.5000) // average and variable cranking time, then time to blend with starting sound