Clutch Fan

[Mc MOPAR]

I saw an episode of engine masters last week where they tested a bunch of different fans to see which one was the best in terms of the least hp to run and although the electric fans where by far the clear all out winner saving about 32hp and 24ft/lbs over a stock fan, I want my car to still look stock.  So I thinking about going with a clutch fan which only took about 15 hp and 9ft/lbs to run.  Any of you guys running clutch fans?  And if so, which one would work the best on my 70 Challenger RT with a 440 engine?

[69bcuda]

When you decide which to use keep in mind radiator to clutch fin clearance. MP recommends 3/4". Some folks have had less and ate their radiators.
 Also a piece of cardboard taped to the radiator can keep the knuckle scrapes down. Just don't forget to remove it when done. 

[1 Wild R/T]

Did the engine masters test account for the load created by the alternator working to recharge the battery of the energy depleted by running the electric fan? While they were at it did they mention how many cars running just the electric fan have overheating issues do to insufficient air flow?

Ok, I just searched & found the video.... Frieberger tells us the electric fan draws 30 amps which honestly is on the low end, then sez that only takes 1 horsepower.... Well he guessed wrong on the horsepower requirements of the fans so why should we trust his guess on the electric fan.... It's standard practice to expect a loss of efficiency turning energy into electricity then electricity back into energy... So how do electric fans gain so much?   

a) they don't
b) they move less air so in actuality the comparison is flawed...
c) Well perhaps the laws of physics cease to exist on your stove! Were these magic grits? I mean, did you buy them from the same guy who sold Jack his beanstalk beans?!

[AARuFAST]

There are  short and long shaft clutch fans.   If you have A/C you need to have the thermo clutch fan. I recall this is short shaft.
You will need a shroud and 7 blade fan.

[734406pk]

Did the engine masters test account for the load created by the alternator working to recharge the battery of the energy depleted by running the electric fan? While they were at it did they mention how many cars running just the electric fan have overheating issues do to insufficient air flow?

Ok, I just searched & found the video.... Frieberger tells us the electric fan draws 30 amps which honestly is on the low end, then sez that only takes 1 horsepower.... Well he guessed wrong on the horsepower requirements of the fans so why should we trust his guess on the electric fan.... It's standard practice to expect a loss of efficiency turning energy into electricity then electricity back into energy... So how do electric fans gain so much?   

a) they don't
b) they move less air so in actuality the comparison is flawed...
c) Well perhaps the laws of physics cease to exist on your stove! Were these magic grits? I mean, did you buy them from the same guy who sold Jack his beanstalk beans?!

  Electric fans are over rated IMO. When you change energy from one state to another, there is a loss. Otherwise perpetual motion would be possible (it's not). We have rotary motion (engine turning the alternator creating electricity=drag) then electrical energy turning an electric motor(s)( plus loss), which turns a fan or two. We have lost efficiency twice. Average loss 10-15 % per energy exchange. The advantage on a dyno is when the electric fan (and electric waterpump) is run off of a battery not being recharged by the engine alternator. Then it's "free energy". Not a real world comparision IMO.

[Mc MOPAR]

Ok thanks guys, a shroud and a 7 blade clutch fan it is for my 440.

[1 Wild R/T]

Electric fans are over rated IMO. When you change energy from one state to another, there is a loss. Otherwise perpetual motion would be possible (it's not). We have rotary motion (engine turning the alternator creating electricity=drag) then electrical energy turning an electric motor(s)( plus loss), which turns a fan or two. We have lost efficiency twice. Average loss 10-15 % per energy exchange. The advantage on a dyno is when the electric fan (and electric waterpump) is run off of a battery not being recharged by the engine alternator. Then it's "free energy". Not a real world comparision IMO.

Damn rules of physics getting in the way again....

[734406pk]

Damn rules of physics getting in the way again....

Yep, constantly!