Results 1 to 8 of 8
  1. #1
    Join Date
    Jan 2013
    Location
    Sweet Home Alabama
    Posts
    31
    Chats
    0

    Default Dual Electric Fans Using Two Stock Aux Fans

    I had been wanting to dump the antiquated mechanical fan for a while on my MJ, and have been looking at various "how-to's" on Dino's and Gojeep's websites, among others. One criterion I had was that I wanted to keep it restorable if I ever wanted to go back to the mechanical fan, so I did not want to cut the existing mechanical pulley shaft as Gojeep did, which was necessary for clearance using the large 16" fans. After looking at various installs, I decided to go a similar route as NAXJA's Slo-sho did and replace the mechanical fan with another XJ/MJ OEM electric aux fan, but with a few mods. These fans pull a lot of air for their size (about 1350 CFM) and I had a couple of spares readily available.

    Step one of course is to remove the old radiator and mechanical fan blade, shroud, and clutch. Then I replaced the fan pulley studs with 5/16" x 24 x 3/4" button head bolts which provide more fan clearance than hex-head bolts .

    Pulley clearance using the stock hex-head bolts:



    Pulley clearance using the button head bolts:



    I wanted to use a quality all-aluminum rad for better side tank heat transfer. This is the one I used from FFD, minus the fans of course. It's a solid dual core all metal that I've read good things about. 200 shipped, here's the link http://www.ffdynamics.com/jeepradB1.html:



    Since welding new aluminum mounting tabs was impossible due to the core being too close to the bottom support bracket, I had to modify it. I fabbed a new support brace out of 1/2" angle aluminum across the bottom and used a Dremel to cut two new slots out for the second fan mounting tabs as below:







    Mockup:



    This setup fits great, and the new aux fan shroud is very close (but not touching) the radiator which increases it's efficiency. I did have to trim the new fan shroud about 1/4" to make sure it was not touching the radiator.

    Since this pic was taken I've swapped out the eight blade fan on the left with a 1999+ 10-curved blade fan like the other as they are quieter and have a higher CFM rating:

    Here's a rear view of the two electric fans installed:



    And a front view:



    I used a Spal PWM-V1 variable speed controller to independently control the new fan, which is now my primary cooling fan. For temperature sensing input to the Spal controller I used the existing dash gauge temp sensor located at the left rear of the cylinder head. I first tried the ECU temp sensor on the thermostat cover, but the gauge sensor on the head provided a larger voltage delta between the Spal LO and HI fan speed settings and gave more precise fan speed-switching control than the one on the thermostat cover. I programmed the controller for the fan LO speed to come on at 190* and the HI speed at 215*. So far these settings are working fine, with the new fan running on LO most of the time. The existing aux fan still operates as always, ON with the A/C or when the temp reaches 220* or so. I did want redundancy just in case the new electric fan or controller failed, so I wired in a dash switch that supplies a ground signal to the aux fan coil relay in the PDU and allows manual control of the existing aux fan. The schematic is shown below:





    I've had this setup up and running for a few years now, and it works well. The new fan when it runs is about 90% of the time in LO, only coming on HI speed when stuck in stop and go traffic. The existing aux fan has never come on it's own (except when I run the A/C of course). I also have noticed a slight MPG improvement since the engine doesn't need to pull the old mechanical fan load anymore. The engine seems to spool up faster too, but this is probably my imagination. I hope this brief writeup helps someone who is considering doing a dual electric fan mod.
    Last edited by Comanche91; 01-21-2013 at 03:50 PM.
    -Don

    ROLL TIDE!

  2. #2
    Join Date
    Jan 2012
    Location
    Houston
    Posts
    15,968
    Chats
    3154

    Default Re: Dual Electric Fans Using Two Stock Aux Fans

    Looks great man! Maybe you included it and I didn't see it, but do you have a link to that radiator?

  3. #3
    Join Date
    Dec 2010
    Location
    japan
    Posts
    3
    Chats
    4

    Default Re: Dual Electric Fans Using Two Stock Aux Fans

    Dual electric fans have to be my 1989.
    http://shim89xj.blog63.fc2.com/blog-entry-120.html

    In Japan, there is a good controller.
    http://shim89xj.blog63.fc2.com/blog-entry-134.html

  4. #4
    Join Date
    Jan 2013
    Location
    Sweet Home Alabama
    Posts
    31
    Chats
    0

    Default Re: Dual Electric Fans Using Two Stock Aux Fans

    Quote Originally Posted by Brasscatz View Post
    Looks great man! Maybe you included it and I didn't see it, but do you have a link to that radiator?
    Link: http://www.ffdynamics.com/jeepradB1.html

    I called FFD and asked the price for the rad only. I don't know what the price is now though as I purchased it a few years ago. I'll edit my post and include the link in the post, thanks for the reminder.
    Last edited by Comanche91; 01-20-2013 at 09:51 PM.
    -Don

    ROLL TIDE!

  5. #5
    Pookapotamus's Avatar
    Pookapotamus is offline Level: Uber Jeep Cherokee Trailer Queen
    Join Date
    Dec 2011
    Location
    Calgary, AB, Canada
    Posts
    1,712
    Chats
    0

    Default Re: Dual Electric Fans Using Two Stock Aux Fans

    what did you think of the quality of the rad? very interested as i am looking for a fan and rad kit for my build.

  6. #6
    Join Date
    Jan 2013
    Location
    Sweet Home Alabama
    Posts
    31
    Chats
    0

    Default Re: Dual Electric Fans Using Two Stock Aux Fans

    Quote Originally Posted by Pookapotamus View Post
    what did you think of the quality of the rad? very interested as i am looking for a fan and rad kit for my build.
    It's a well constructed radiator. I have been through quite a few single core and three core rads and this one performed the best for me.
    -Don

    ROLL TIDE!

  7. #7
    Join Date
    Apr 2016
    Location
    Portland, Oregon.
    Posts
    774
    Chats
    0

    Default Re: Dual Electric Fans Using Two Stock Aux Fans

    4 years later this is my reference for my next project. Gotta love when Google brings me back to xjtalk.

    Sent from my SM-G935V using Tapatalk
    Last edited by MattybPDX; 06-06-2017 at 03:09 PM.

  8. #8
    Join Date
    Aug 2009
    Location
    Asheville, NC
    Posts
    7,955
    Chats
    39048

    Default Re: Dual Electric Fans Using Two Stock Aux Fans

    Quote Originally Posted by MattybPDX View Post
    4 years later this is my reference for my next project. Gotta love when Google brings me back to xjtalk.

    Sent from my SM-G935V using Tapatalk
    Darn near everything I look up online when I'm stuck on something, whether it be my XJ or someone else's XJ... One of the first results usually brings me back to so of course I have to select that one for help...
    FORMER GREEN XJ CLUB MEMBER
    IF YOU DON'T STAND BEHIND OUR TROOPS, FEEL FREE TO STAND IN FRONT OF THEM!!
    DOING SOMETHING JUST BECAUSE YOUR BUDDY DOES IT THAT WAY MAKES AS MUCH SENSE AS SHARING TOOTHBRUSHES

Similar Threads

  1. Replies: 8
    Last Post: 08-04-2012, 11:40 AM
  2. Need help with my fans
    By gordo in forum General Talk
    Replies: 0
    Last Post: 08-03-2012, 07:52 PM
  3. Dual Electric Fans or Grand Cherokee Fan Clutch?
    By jeepxj95 in forum Modified
    Replies: 42
    Last Post: 11-05-2011, 11:16 PM
  4. Electric Fans?
    By jeepxj95 in forum Modified
    Replies: 31
    Last Post: 11-05-2011, 11:16 PM
  5. 2 10" Mishimoto Fans
    By afbond03 in forum For Sale
    Replies: 0
    Last Post: 08-15-2010, 01:29 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •