Compare the Citroens file:
[DRIVELINE]
ClutchEngageRate=0.9 // Auto clutch gradual engagement rate from neutral to 1st gear
ClutchInertia=0.0148
ClutchTorque=900.0
ClutchWear=0.0
ClutchFriction=17.225
BaulkTorque=500.0
SemiAutomatic=1 // whether throttle and clutch are operated automatically
AllowManualOverride=1 // whether to allow manual shift overrides when using auto shifting
UpshiftDelay=0.07 // delay in selecting higher gear (low for semi-automatic, higher for manual)
UpshiftClutchTime=0.09 // time to ease auto-clutch in AFTER upshift (0.0 for F1 cars)
DownshiftDelay=0.07 // delay in selecting lower gear (low for semi-automatic, higher for manual)
DownshiftClutchTime=0.09 // time to ease auto-clutch in AFTER downshift (used to be SemiAutoClutchTime, note that the shift will complete significantly before the clutch is fully engaged)
DownshiftBlipThrottle=0.83 // amount of throttle used to blip if controlled by game (instead of player)
WheelDrive=FRONT
GearFile=GearBox_FWD.ini
FinalDriveSetting=0
ReverseSetting=0
ForwardGears=6
Gear1Setting=0
Gear2Setting=14
Gear3Setting=23
Gear4Setting=29
Gear5Setting=34
Gear6Setting=37
DiffPumpTorque=0.0
DiffPumpRange=(0.0, 0.00, 0) // differential acting on all driven wheels
DiffPumpSetting=0
DiffPowerRange=(0.0, 0.05, 9) // fraction of power-side input torque transferred through diff
DiffPowerSetting=8 // (not implemented for four-wheel drive)
DiffCoastRange=(0.0, 0.05, 21) // fraction of coast-side input torque transferred through diff
DiffCoastSetting=10 // (not implemented for four-wheel drive)
DiffPreloadRange=(80.0, 5.0, 5) // preload torque that must be overcome to have wheelspeed difference
DiffPreloadSetting=0 // (not implemented for four-wheel drive)
To the BMW's:
[DRIVELINE]
ClutchEngageRate=0.9 //Auto clutch gradual engagement rate from neutral to 1st gear.
ClutchInertia=0.0148
ClutchTorque=900.0
ClutchWear=0.0
ClutchFriction=17.225
BaulkTorque=800.0
SemiAutomatic=0 // whether throttle and clutch are operated automatically
UpshiftDelay=0.07 // delay in selecting higher gear (low for semi-automatic, higher for manual)
UpshiftClutchTime=0.005 // time to ease auto-clutch in AFTER upshift (0.0 for F1 cars)
DownshiftDelay=0.07 // delay in selecting lower gear (low for semi-automatic, higher for manual)
DownshiftClutchTime=0.20 // time to ease auto-clutch in AFTER downshift (used to be SemiAutoClutchTime, note that the shift will complete significantly before the clutch is fully engaged)
DownshiftBlipThrottle=0.70 // amount of throttle used to blip if controlled by game (instead of player)
WheelDrive=REAR
GearFile=GearBox_FWD.ini
FinalDriveSetting=0
ReverseSetting=0
ForwardGears=6
Gear1Setting=0
Gear2Setting=14
Gear3Setting=23
Gear4Setting=29
Gear5Setting=34
Gear6Setting=37
DiffPumpTorque=200.0
DiffPumpRange=(0.0,0.05,9) // differential acting on all driven wheels
DiffPumpSetting=6 // was 6 !!!!!!!
DiffPowerRange=(0.0, 0.05, 9) // fraction of power-side input torque transferred through diff
DiffPowerSetting=8 // (not implemented for four-wheel drive)
DiffCoastRange=(0.0,0.05,21) // fraction of coast-side input torque transferred through diff
DiffCoastSetting=6 // (not implemented for four-wheel drive)
DiffPreloadRange=(5.0, 5.0, 5) // preload torque that must be overcome to have wheelspeed difference
DiffPreloadSetting=2 // (not implemented for four-wheel drive)
Differences in torque. However key passage above:
Citroen has a 2.0 litre engine file.
[ENGINE]
RevLimitAvailable=1
SpeedLimiter=1 // Whether a pitlane speed limiter is available
Normal=2_0_engine.ini
RestrictorPlate=2_0_engine.ini
BMW a 1.6 you can see:
[ENGINE]
RevLimitAvailable=1
SpeedLimiter=1 // Whether a pitlane speed limiter is available
Normal=1_6_T_engine.ini
RestrictorPlate=1_6_T_engine.ini
Perhaps swap the 1.6 for a 2.0.