Factory Fan CFM Range

Discussion in '80-Series Tech' started by PKP80, Jul 10, 2008.

  1. PKP80

    PKP80 SILVER Star

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    I'm trying to figure out the rate of flow CFM Cubic foot per minute that the factory fan setup provides through the range of RPMs. Idle, 1, 2, 3, 4,000, or a min vs. max number. I've tried a number of searches and even asked my local Toy Stealer when I picked up a part the other day (he had to ask what CFM meant, lol).

    Anyone have an estimate? Ballpark/estimates are fine. CDan, where you at?
  2. NLXTACY

    NLXTACY Mud Life Sentence

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    Assuming you are talking about the factory mechanical fan and not the JDM factory aux. electrical fan? I don't have an answer either but just wanted to clarify.
  3. Tools R Us

    Tools R Us

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    I haven't been able to find that number. A buddy that designs industrial blower systems looked at mine, did some quick math and his guess for full on flow was a big number. Also he observed that the fan design is a very powerful type, designed as much for power as flow. This is needed because the coolers are relatively thick and stacked, making for a pretty good flow restriction, so the fan needs to pull a good suction to produce flow through it.

    Having the CFM number is worthless without the restriction number. It's relatively easy to blow X CFM of air around, add the restriction of a cooler it gets more difficult. Most aftermarket fans are rated ether open or with a single thin cooler, it takes much more power to suck air through the thick, flow restrictive coolers on the LC.
    Last edited: Jul 10, 2008
  4. PKP80

    PKP80 SILVER Star

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    I am talking about the mechanical Fan. I ask b/c I want to replace the factory fan with an aftermarket electrical, reason being that I am no running a fanshroud b/c of the body lift and clearance issues. Also be nice to over ride the system and turn it off or leave it on at a higher intensity when crawling the rig. Looking to compare the two.

    Any info appreciated to help w/ the decision.

    I am adding a pusherfan (1500cfm) for the time being.
  5. Tools R Us

    Tools R Us

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    I would look at stock fans on V8's like fords and Lincolns. The main problem is the design of the coolers, the LC is designed to have a powerful belt driven fan. Most electric fan designs have thinner coolers with much more surface area (taller and/or wider) per gallon of coolant, making them much less airflow restrictive. Electric fans are good at moving air, but not very powerful at sucking it through restriction.
  6. e9999

    e9999 You want to do what...? Moderator

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    been meaning to stick an anemometer behind the fan. Will do it when I get a chance. Should be good for ballpark figure.
  7. jfz80

    jfz80 SILVER Star

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  8. PKP80

    PKP80 SILVER Star

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    Thanks for the links. It has been on my mind and once my Scanguage hit 220 on the way to the CON and I was having to blast my heater in 100deg. humid heat on the trail, I figured that it is time to make a move and try a few things out.

    I will flush the Rad first and foremost, see what that does for me then move on to the pusher, and if need be go full Aux fan setup and maybe just do a Ron Davis Rad to go with it. Mount it in the rear on top of the cage:flipoff2: who knows!:beer:
  9. Waggoner5

    Waggoner5 SILVER Star

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    I mounted a MK8 electric fan in my 80 series shroud and it cools the truck as good as the mechanical. The Ford fan is about 1" smaller diameter than the LC and needs some minor tab trimming. I used 4 bolts with 1/2" spacers and mounted the fan flush with the 80 shroud. I would also buy a Delta DC Controller to control the fan. It will handle the amperage and change the fan speed according to the water temp. Yes temp sensor is included. Pics included.
    G
    clean_005_001.jpg Picture 355.jpg
  10. PKP80

    PKP80 SILVER Star

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    Gary, thank you. One issue I'm having is that I don't have a shroud anymore. I will look into getting a new one and trying this setup out. Thanks.

    They say you get a hp gain (8-15hp) ditching the mechanical fan. Feel a difference?
  11. Waggoner5

    Waggoner5 SILVER Star

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    I didn't drive the truck with a mechanical fan so I don't know. I do know that the loss of the mechanical fan will free up HP, but the extra load on the alternator because of the high current fan will probably negate any seat of the pants feeling. The nice part about the Delta control box is that it only runs the fan at the needed speed to keep the engine at temp. One thing I would do on the controller is match the fan operating temp to just below the thermostat temp instead of the 180 degree setting. Its a matter of changing jumpers on the controller.

  12. robmir

    robmir

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    Yesterday I was looking at a brand new Dodge Ram 2500 HD with the Hemi engine and it came with a big extra thin radiator ( my jaw droped to the floor at what thin it was) with a mechanical fan at the passenger side, a thin a/c condenser with a electric fan and shroud at the driver side, and in the lower front of the engine radiator a small and thin transmission cooler and a very small steering fluid cooler. And we are talking about a extra heavy duty pickup designed to tow a lot.
  13. hj60

    hj60

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    Dude! You almost made me snarf my iced tea.
    I'm still laughing.

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