[Winfield1990]

With a rear mounted engine or motor which would be th most efficient way of cooling , I read somewhere in a search with pros and cons that air cooling out the rear which im guessing blowing the heat away and not sucking in since its out the rear in the low pressure area.

Would be the most efficient but I am unsure , I would think radiator cooled with the radiator WAY in the front with the engine in the rear would have additional losses from pumping distance.

If air cooling through the rear is the most efficient choice would using an electric fan vs a fan ran from the motor itself be more efficient and offer adequate cooling with a temperature sensor regulating the fan.

Just slowly compiling ideas for a project cars a while down the road , I would want the car to be an economy car full electric but I may decide that I would just make it a hybrid driven only by the motor and the diesel engine just charges a supercapacitor... top speed around say 65 gears to have tons of torque to make up for the weight of the batteries..