Building a new fan set up ?

So I want to build something like dirtbounds set up. My buddy has a good hook up from summit, so I can get fans for cheap. I wanted to do 3 fans just like they do. I was thinking of wiring them all to a switch. Two to one switch and the third to another so I can control them. Will that be ok or no? Im worried about my AC not working once I cut the wires. Unless I wire the 3rd fan to the Aux fan so it still comes on just a new fan. Have the other two run at all times, what do you guys think?

How I was going to do my DBO fan kit was 1 on the stock aux. fan wiring. 2 on the fan controller. But, my AC doesn't work anyways. So I have the 2 outside fan on the lower temp output of the controller, and the middle one on the high. Works good. I am also going to be installing a 3-position master switch. OFF, which will cut the ground, disabling the fans, for a water crossing or whatever. Normal ON, and Override ON which will run all of them until the switch is in a different pos.
You CAN have them run all the time, but why waste the power? Use a controller, whether it's adjustable or not.

Mine is setup so the computer (Painless) controls one fan, second is controlled by the factory in tank switch, third is on a switch. 3rd switch is also connected to the AC so if I flip the AC on the fan will also come on.

Johnnie Walker said:

How I was going to do my DBO fan kit was 1 on the stock aux. fan wiring. 2 on the fan controller. ....

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This is how I have my DBO fan's wired up. The 3rd fan (via the OE AC controller) has only come on maybe 2 times this Summer and only for moments... while parked, idling, AC running, getting hot. Once the 3rd fan kicked on it dropped the temp down quickly and then stopped.

My thinking was to utilize the OE controller and also to have 1 fan per 1 relay. Also having a bit of backup failsafe in case my DB Controller goes out I'd still have 1 fan to limp home and help keep temps in a reasonable (albeit only briefly) range.

What's your intended use of the Jeep? Towing, ever? Sand?
I ask because the DBO setup moves slightly less air than stock and depending how you set up the fan controls, might under perform.
I'd really recommend two fans ON at 205, controlled independently of the ECM, with the ECM turning one fan on as usual. That's if you really want the DBO setup. I'd push the Taurus fan installed & controlled independently of the factory AC fan, though, for peace of mind.
A good argument can be made for keeping mechanical fans. They move a shit-ton of air and don't need any wiring. The ZJ regular-duty fan clutch for the 4.0 is a good upgrade for severe use in an XJ.
I say all this from having way over taxed my own electric fan setup while towing the other day. It even ran 10 or 15 degrees hotter without the trailer & ambient temps around 100 degrees on the freeway. Around town... whatever, it'll be fine.

My setup is a little different since I do not have the DBO fan kit. I have the Derale dual fan kit which needed a bit of work to fit it/them. The both run completely independent of each other i.e. I use two set of everything needed to make them work including thermostat switches that turn them on within 5* of each other which is purely coincidence since the turn on temperature is the same(in theory)for both. Either one will run and on rear occasions they will both be on at the same time at about 215* on the dash gauge.

One fan could be turned on by a toggle switch in the dash panel. It also connects to the AC compressor and cycles with the compressor. The other is connected to the AC switch and run continuously when the AC is turned on mimicking the mechanical fan. There is no off switch in the system. In that way, I do not have to remember to turn them on.

It is rather ironic that any one fan will keep the 4.0L at about the same temperature that the mechanical fan used to keep it. In 95*+ here in Jacksonville FL, and travelling on city streets at the rate of 5 miles in 45 minutes, one fan will run continuously while the other will come on for about 3 minutes every 15 minutes. If the AC is on then the temperature will remain below the 210* mark. With the AC off, if the XJ get moving above 45 MPH for 5 minutes or more both fans will turn off and the temperature will remain below 210*.

techno1154 said:

I have the Derale dual fan kit which needed a bit of work to fit it/them.

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Which kit did you use and what was required to make it fit?

I recommend anyone contemplating installing electric fans install the highest quality fans available (Spal). I have spent a huge amount of money testing various fan setups and in the end I would stick with the stock type fan setup were it not for the noise. The noise is the primary reason I went to electric fans. You will NOT get better cooling using electric fans unless you also upgrade basically every other component in the cooling system.

Talyn said:

Which kit did you use and what was required to make it fit?

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Cut the crap out of the plastic shroud. I had the same kit on mine. Can get them for Summit or Jeg's, only dual setup they carry. It moved some air but was too close to the engine and radiator for me. I needed to move the radiator ahead ~1" and it would have been fine.

https://plus.google.com/u/0/photos/117016052099699625203/albums/5472446900206159553

I have seen many overheat with 3 10 elect. fans. The stock mech with a ZJ clutch and a late model curved blade elect has yet to fail me or those that I know, that have a good condition cooling system.

I just started stopping by a local jeepspeed owners house and helping him out as I could. He knows very little of Jeeps (very good mechanical guy though) but bought a completed Jeep to compete with. He has done well with a 2nd place even. He lost the motor last race and was replacing it when I came into the picture. He also bought a champion all alum radiator. He had it installed one evening when I came over and he said he was going to get a 3 fan elect shroud to upgrade it. I tried to talk him out of it. He said it was fine. I did point him to dirtbound and he bought his 3 fan shroud.

Well he got it all finally buttoned up, 2 days before having to leave to Vegas to Reno (last weekend). He made it about 2 miles in the race till I noticed his blip on the irc tracker screen wasnt moving. It had overheated Badly and they had to sit about 20 mins for every 2-3 miles. They barely made it to first pits before cut off time and at that time they called it them selfs, knowing another 570 miles would not be poss.

I will see if he lets me talk him into the stock very good mech fan and late model elect, this time.

Weasel said:

Cut the crap out of the plastic shroud. I had the same kit on mine. Can get them for Summit or Jeg's, only dual setup they carry. It moved some air but was too close to the engine and radiator for me. I needed to move the radiator ahead ~1" and it would have been fine.

https://plus.google.com/u/0/photos/117016052099699625203/albums/5472446900206159553

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Weasel is correct in every way except I did not cut my unit as much as he did. Instead I moved the fans as far to the passenger side as I could leaving about a 3 inches of uncovered radiator on the driver side. However, I still had to massage the fan shroud a bit to get it to fit next to the steering box.

I did not have to move the radiator. After replacing the alternator/AC compressor bracket with one from a 1996 (the same year as my XJ) 4 cylinder including the two idler pulleys, there is almost an inch of space between the fans and the engine components. I also use a serpentine belt from a 4 cylinder XJ. I also cut a bit out of the top radiator bracket so the fans could be moved as far forward as possible without touching the radiator. The front cross member/ bottom radiator support have a 1 inch angle bolted to it and the fans bolted that angle bracket. Reason being the fan shrowd measures 13.5 X 28.8 inches and the radiator fan opening (so to speak) is 12 X 31 inches.

I installed these fans in May of 2004 and they have served me well. I have had no complaints or issues what so ever with them. However, knowing what I know now, I would had stayed with the OEM mechanical fan. Reason being now the AW4 seem to run hotter or maybe I only notice that because I now have a temperature gauge on the AW4 which I did not at the time of installing the electric fans.

Bear in mind though that these fans are hungry for AMPS. The higher over 12 volts you could keep the system, the happier they will be.

Anyone want to weigh in on Taurus / Volvo fan (4500 cfm on high) vs stock (or ZJ) mechanical? I'm interested in keeping the electric for the economy upgrade and because it amuses me but when towing I need more airflow than my 2100 Zirgo provides.

My intended purpose is to drive around town when wanted then wheel it. I drive to and from trials, but Even in town on a 80 degree day the jeep runs 230. And when I start climbing hills it stay about 240. I have the stock clutch fan and stock aux fan to. Im looking to keep her cooler. Im doing a new rad this winter, water pump, and t-stat as well. So since im doing all that I want to upgrade my fans and make it work better. I like dirtbounds idea, but I dont want to spend that kind of cash (Not trying to say I wouldent) But I enjoy finding better ways to do things and cheaper if can be. I also enjoy building it myself which is big to.

230? 240? You have a cooling system problem. Find and fix it. Electric fans will not help you unless the problem is a fan clutch, in what case a new one will be cheaper and work better than anything but a Taurus swap

I'd just like to throw out there that I bought a rig recently with the DBO kit and it was running on one fan and was fine driving around and at idle. I couldn't even tell until I took it down and thrashed it around the river bank and it started to get hot. One of the fans was hooked to an existing temp sensor that was dead and the other fan had come apart and ate itself. I think it was most likely a poor install job by a previous owner and not a defect, but I talked to DBO and got a great price on a replacement. After wiring the two working fans to the same toggle switch on the dash I no longer have a heat issue when crawling around and thrashing it in the deep sand. Outside air temps both times were about 85 degrees or so.

I think you definitely have a cooling system problem if you're running those temps just driving down the road and need to get that figured out first. No amount of airflow is going to cool your system enough if it isn't moving the water through the radiator. And don't be so fast to disregard the DBO kit unless you've tried it yourself. These fans move an incredible amount of air.

Also vents towards the front of your hood will help a small amount with towing temps, towards the rear or over your exhaust manifold will help with the low speed stuff. I'll soon be shimming the rear of my hood to make a ghetto cowl and let my fans blow some of the trapped hot air out the top instead of through the holes in my firewall, cabin is already too hot without the carpet to insulate it.

I know that my gauge temp is about 10-15 over what actual temp is. I have confirmed with a heat gun. May be the case for others also. Before and after the DBO fan swap, going up the mountain to big bear my temps would rise. I would pull off and let it cool down. I think that it is more of a trans/cooler problem tho. As if the auto trans warms up enough it will heat the coolant as well. I will be bypassing the stock "cooler" and running an aftermarket cooler/trans temp gauge.

been running electric fans since 2005... they rock
I have not had any issues with over heating or have i ever run into anyone in person on the trails that has in oh 10 years.(so the number of people with this issue must be a small percent) I ran two factory electric fans for over 8 years with no issues (never overheated). now when one fan broke due to age last winter fest I bought the DBO fan shroud (very well made hi quality shroud) and sourced my own fans I have two running on thermostat and one is set to switch for backup. just as with the factory units the two fans keep my MJ at 195/200 all the time. and when i run the third fan the gauge never moves off 195 (thermostat opening) if you have overheat issue with 2 or more electric fans you have to have some other issue. . I do agree that spending 3 times as much... cause that's what is is..on top shelf fans is a good idea for longevity.

It isn't the trail that is demanding. Its towing and or sand.