Mechanical Fan VS Electric Fan

Rice Nuker said
Here is an additional item. How much cfm you think a big *** electrical fan pushes (pulls)? Probably 3000. Eating 50 - 60 amps. How much horse power does it take to make 60 amps in your alternator? What am I nerd scientist? I don't know. My guess is 10.

When a thermostatically controlled clutch fan is active it is moving easily 5000 - 8000 cfm depending on the vehicle (fan blade / shroud). Most after-market electric fans push about 2000 or so cfm. It varies based on price mostly. Just look at the cfm of elec fans on summit. Then look up the cfm of thermo-clutch fans.

Where do you get 50 or 60 amps from? 25 or 30 amps is more realistic. Also where does it say you need 8,000 CFM? If your radiator is properly sized for the engine and it's HP level you shouldn't need that much air. Of course there are variables such as rate of coolant flow and ambient temp.

Rice Nuker said
A good working thermostatically controlled clutch fan with a modern designed fan blade and a fitting shroud is the best for a street v8. I have never had an over heating issue running a stock thermo-clutch fan with or with out a shroud unless I had a hole in my radiator and the fluid leaked out or my radiator was completely clogged with 25 years of rust. Ive lived in the south most my life and raced many days in 100 degree weather. Nice thing is a thermo-clutch will handle the temp for you and use HP only when cooling is needed. Most my thermo-clutch fans were dis-engaged to the extent that you could stop the blade with a big stick while the engine was running. I doubt it was consuming any HP (this is during idle). The down side is it may decide to engage while you are racing and rob you of some horses.

How much does your entire clutch fan assy. weigh? Remember, that's rotating weight. That mass and inertia have to be overcome every time the engine RPM changes. That's what robs HP even in freewheeling mode. Even if the fan itself is negligible (which it's not) the pulley, belt and clutch still turn at engine speed.

Rice Nuker said
I constantly hear people having overheating issues while using aftermarket electric fan(s) and they do every other thing, rather than just put a clutch fan on it most the time. I have also heard several people solving their overheating issues by dumping the aftermarket elec fan (s) for a clutch fan with a shroud.

That's because the radiator's cooling capacity is too small for the HP they're making and they need to pull more air through the radiator.

The only reason for having a propeller on the front of your engine is if you plan on leaving the ground, but then you'd need a bigger propeller. Engine driven fans are cheap and simple. Other than that, electric is the way to go.