Mechanical Fan VS Electric Fan
Sometimes I can't help being the antagonist, in order to bring some intelligent debate? :hello1:
If mechanical fan clutches were as efficient as temperature controls are things would be different. During periods of max cooling requirement a fully locked up mechanical fan is hard to beat. Cruising over 30 mph I do agree that mechanical fans don't completely unlock causing some loss in efficiency.
Now a clutch driven mechanical fan with a telemetry ring for control Hmm????? :happy3:
I concur on the power relationship and power transition. You turn your elec fan with your alternator which robs power from your crank. It all is just transition of energy and there is loss in transition so the less transition the better.
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.
Also, v6 factory electric fans push (pull) more cfm than most any after-market elec fan. Like on a 93 taurus.
http://www.rockauto.com/catalog/moreinfo.php?pk=688728
2 or 3 speeds with quite amazing cfm and cheap as hell compared to aftermarket. Get one at the junk yard and mod it.
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.
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.
Electric fans are probably good for remote radiators, space constraints, and drag race apps. There is no other practical reason to run one that I can come up with.
Good quality thermo-clutch fan with proper shroud.