I've never discovered if rf1 takes into account the air flow drag caused by traffic (I've tested the theory widely on nascar cars/tracks without a final conclusion). But if you want to give the engine heat a more important role, try setting the following params on the engine ini:
FuelConsumption=3.700e-005 // affected by throttle position and engine speed
OptimumOilTemp=100.5 // degrees Celsius at which engine operates optimally
CombustionHeat=50.5 // degrees Celsius added per liter of fuel burned
EngineSpeedHeat=8.200e-004 // heat added linearly with engine speed
OilMinimumCooling=4.500e-003 // heat dissipated without oil/water transfer
OilWaterHeatTransfer=(2.400e-001,8.250e-005) // heat transfer from oil to water (base, w/ engine speed)
WaterMinimumCooling=2.500e-003 // base heat dissipated without velocity
RadiatorCooling=(3.300e-006, 5.700e-006) // cooling rate with velocity (base, per setting)
With this config the pilot can't do a race at full throttle (like in karting), the pilot is forced to manage temp by going faster (more air flow in the radiator) or lower revs (less heat generated by engine friction) or using less power (throttle) on hard turns.