Engine Cooling fan dyno comparison

The magnitude of the result is surprising, but the result itself is not. The reason no shroud made more power is because it's not taxed with drawing as much air through the radiator. So the question is, how does it *cool*? Or...install an electric fan.

I kinda cringe everytime I see a mustang or another vehicle with an engine driven fan and no shroud. The shroud is there to direct the air through the radiator. My 96' jeep 4.0 had the top section of the fan shroud missing above the clutch fan. When I re-attached the top section, I actually noticed an improvement in my coolant temperature. I would rather make slightly less hp and have a more efficient cooling system.