[AMC-List] more electric fan stuff

[Teamamc <Teamamc@xxxxxxxxxxx>]

            Fans are not designed for creating positive pressure! They can only put out 5 to 6 in H20 (.18-.22psi). They are designed to move air from one location to another not to pressurize it. This is referring to the typical fans you see on Ebay.

            Okay let's go with a 2001 Celica GTS for comparison.

            Specs: 
              a.. Displacement: 1.8 litres (1,796 cc) 
              b.. Bore x Stroke: 82.0 mm x 85.0 mm 
              c.. Compression ratio: 11.5:1 
              d.. Horsepower: 180 hp @ 7,600 rpm 
              e.. Torque: 130 lb.-ft. @ 6,800 rpm 
            Okay now that we have the specs of the motor. Let's see how much air it consumes.

              a.. v = (pi/4)*(bore)^2*(stroke)*(Ncylce)*(# Cylinders) 
              b.. v = 3.14/4*(3.228in)^2*(3.346in)*(7600/2)*(4) 
              c.. v = 416369in^3/min(1ft^3/1728ft^3) 
              d.. v = 241.0 CFM 
            Mind you this is 100% VE. So say at a more reasonable 90% (VVT-I helps increase this number thus creating more power) so that leaves us with: 

              a.. v = 241.0 CFM * 0.9 
              b.. v = 216.9 CFM actual 
            Now I am sure you are thinking that the fan is forcing the extra CFM into the motor right? Wrong. The air will actually just pass through the blades in a reverse direction thus providing no benefit to power. But this is the thermodynamic method of finding the power a fan needs to move and slightly compress air (between 0.18-.22psi). But lets say it will magically create 5 psi boost for a "30hp" gain.

              a.. Fan air power = w * Ht 
              b.. Fan air power = (216.9cfm)*(5psi)*(144in^3/1ft^2)(1hp/33000ftlb/min) 
              c.. Fan air power = 4.7 Hp 
            Okay and 4.7hp = 3.5kw of power. 
            Divide that by 13 volts (average operating battery voltage). Now that leaves you with 270 amps of power. So now I have to ask does your friend have a 270 amp inline fuse for his monster fan? No I don't think so, and this is with 100% efficient motor as well. So it would actually have to consume more power than that. But oh wait....the factory rating on most alternators are around 80-90 amps (approx value). Seems his fan is consuming 3 times as much as the alternator can put out. Hmm....odd.

            Divide that by 13 volts (average operating battery voltage). now that leaves you with 270 amps of power. So now it leaves you to wonder if you would need a 270 amp inline fuse for this monster fan. I have yet to see anything with a 270 amp fuse in a car. mind you this is with 100% efficient motor as well. So it would actually have to consume more power than that. Another thing to consider is that the factory rating on most alternators are around 80-90 amps. So an electric turbo would be consuming 3 times as much power as the alternator can put out.

            So a long story short an electric turbo just won't create more power than what they consume to run them. 
           
     
        
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