The plain and simple answer to your question is:
100% water as engine coolant, will transfer MORE heat from the engine to the radiator than any “mix” of ethylene glycol and water.
The majority of answerers here are not understanding this, and answer improperly.
Without a complicated, scientific sounding answer, just understand that water holds and transfers MORE heat than any water - ethylene glycol mix. Pure ethylene glycol is even worse!