Shroud or 4 electric fans?

General Mopar Tech Discussions

  1. multimopes

    multimopes FBBO Gold Member FBBO Gold Member

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    I think I read several times on here with cooling issues when using a shroud & mechanical fan, the fan should be either 1/3 of the way into the shroud or 1/3 the way out. I don't recall which. I have 2 electric fans and hate them. They are noisy & pull way too much juice for my liking. At idle they pull 20 amps each. I bought the car with 1 electric fan & no shroud as it was a race only car. I don't have any original shroud or factory fan. Good Luck!
     
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    • Sinitro

      Sinitro Member

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      In my 70 RR, I have a built 383, shroud, clutch fan, 22" radiator modified withe a 3 core Modine section. In SoCal it does get hot, the RR runs about 185 and up to 200 if in traffic. Biggest negative for electric fans is the juice they draw, up to 30 amps on start up and 15-20 amps running, so U better do some electrical upgrades if going to electric as these basic #s far exceed the stock OE electrical system capability. But as mentioned previously by others, recheck the timing and fuel/carb setup... In my humble opinion, Ma Mopar designed pretty robust OE cooling system..

      Just my $0.02... :steering:
       
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      • RJRENTON

        RJRENTON FBBO Gold Member FBBO Gold Member

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        IMO...
        "shrouded mechanical fans are not limited to CFM they can draw".... Shrouded or un-shrouded mechanical fans ARE CFM limited by RPM, number of blades, pitch angle of the blades and their STATIC PRESSURE capabilities and the temperature of the air being moved (density in pounds/hour) as higher air temperature being moved (lower density) actually results in less air being moved per unit of time.
        Shrouded, 7 blade clutch coupled mechanical driven fans seem to work the best. Electric fans, either pushing or pulling, mounted directly to the radiator core, only provide air flow based on the fan's presented area x the number of fans used, as there are areas of the radiator don't have coverage....in spite of what the suppliers note in their advertisements, as propeller fans usually have poor static pressure capabilities vs CFM flows (inverse relationship.....higher Static pressure results in lower CFM flows).
        BOB RENTON
         
      • RemCharger

        RemCharger Well-Known Member

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        Note that water wetter, works best when wetting straight water. Thats what I'd try, it works damn good.
         
      • Gerrs69rr

        Gerrs69rr Well-Known Member

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        Hell yeah, blow the dust off and let's get on the road!!!
         
      • diesel_lv

        diesel_lv Well-Known Member

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        My '67 came w 26" and air, 383. No 496" w air. I've tried 3 different electric fan setups w shrouds. 2 spal fans, 2 Ford contour fans, 2 CCI fans. All in shrouds w covered slots for more airflow. At idle, all did well, but on interstate, all restricted airflow with temps climbing over 220. I have serpentine setup so am limited to type of mechanical fan. Also only 3" of room between w/p pulley n radiator core. Ended up w a 19" 11 blade nylon fan from Chevy 496 truck. Direct drive, no fan clutch due to restrictions. With factory shroud. I'm in AZ w 120+ temps. Idles for over 2 hrs, oops, at 184° and interstate at 176°. Largest, most blades mechanical fan and shroud!!!! Also make sure your w/p pulley is 20-30% smaller than crank pulley w/ a/c. I also run 50/50 coolant and add 2 bottles of water wetter.
         
      • mpro69rr

        mpro69rr Well-Known Member

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        Well, it looks like an overwhelming vote for engine driven fan and shroud! Not one person said go electric! I will be going the fan and shroud route, $184 vs $500. Thanks everyone, I appreciate all the advice!
         
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        • Dennis H

          Dennis H FBBO Gold Member FBBO Gold Member

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          Green coolant. Hayden fan. 180 Superstat. Good gauge or carry a thermal gun.
           
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