Electric Fan Conversion for the wide rad

[Agnem]

If your considering doing an electric fan conversion, you should read the below thread and also George's OBS install to get ideas on how to go about it. Depending on your radiator, you may need one of these methods, or a modified method to get your fans to mount. In either case, these articles show what can be done. Many have said that electric fans cannot cool as well as the factory fan. Neither of these authors have as of yet encountered a situation they couldn't handle. If we do, or if you do a conversion and it doesn't work out, tell us about it!

The following thread has been cleaned up for inclusion in our tech library.

Electric Fans in an 83' F-250HD manual trans with no AC

Note: We lost the picture formatting when this was moved to the Tech Articles. Please click here for the main album which may make it easier to follow along.

I completed my electric fan conversion on the Moose Truck over the weekend. I used fans supplied by Darrin Tosh, and they were both out of mid 90's model Taurus sedans with 3.8L V-6's. They are 2 speed fans. My plan was to mount them up, and operate them in tandem in low speed mode, and then have a provision for high speed. It's necessary to run them both for if only one is running, it could draw air from the back side of the one that isn't. The Moose Truck is an 83, without Air Conditioning, so it has the more unusual extra wide, not so tall radiator. This puts me at a distinct advantage for this conversion, as the core is 16" high, which is the same diameter of the Taurus fans. Finally! An advantage to having this style rad! Let's get into the picture story.....

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This shot shows the factory shroud and fan as it compares in size to the two Taurus fans. Note that in factory trim, the fan is already positioned to extend below the bottom of the radiator core by almost a full third.

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In this shot, the fan is repositioned to more closely portray the way it actually sits in the shroud. Because of the 2" body lift, the fan is now way below the radiator, and there is a big gap at the top. Had I been having cooling issues, it would have been easy to see why. By this point, I'm pretty convinced that this is going to work out great.

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Research on the Taurus fans suggested that they have a very hefty start up current, and draw upwards of 40 amps EACH. I knew the 70 amp factory alternator wouldn't be up to that, so I upgraded it to a Lestek 135 amp model. I redid the wiring at that time as well.

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The Lestek barely fits. The hot wire on the back is closer to good grounds then I would like, but as long as the belt doesn't stretch, I should be good.

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Looking down we see the amount of room with no fans at all.

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Using the factory shroud as a guide, I then overlaid the electrics to see how they might fit. It looked like the best option was to trim them where they would meet in the center. By cutting them like a jigsaw puzzle, I could retain the mounting ears that were available.

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A sawzall made quick work of the necessary trimming, and I removed a small corner from each unit. I cut a slot at the necessary spot so I could interlock them together. If I had taken my time, I could have used my milling machine to do the job perfectly, but it was hot, and time was short.

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I grabbed some flat bar stock and came up with a couple of cross braces. I decided to weld these in the center and brace them at the end I planned to use as a support.

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Knowing that I would be posting these pictures here, I felt it necessary to post an obligatory picture of the pair.

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Here the completed assembly has been dropped in to test fit.

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Better lighting.

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This view shows how things look clearance wise.

 

[Agnem]

Electric Fan Conversion Part 1 & 2

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Under the truck now, looking up.

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Here the completed brackets have been painted. The welding included tacking the bolts in place so that I would essentially have studs to mount the fans on.

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Here is the completed assembly just prior to installation.

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The electric fan shrouds were deficient in the material available on the sides. To compensate, I made an air barrier by sandwiching a lenght of 1" hose, like what I use for a road draft tube, in between the mounting bracket and the radiator. The factory shroud uses 6m X 1" metric bolts. I had to get some about twice as long.

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All done, and wired up!

RESULTS - I performed some static tests prior to the road test. I activated the fans on high speed, so I could see what the total "windage" would be like. Whoa! Just keep your hands and feet away from the intake please, and you'll be fine. These fans put out some serious air movement. I could feel a serious breeze holding my hand in front of the push bar on the Moose Truck. That's like a foot away from the rad! With my hand in front of the grill, I was pretty sure that this area was now strictly off-limits to all bugs, birds, and small animals. With the hood closed, I could feel a strong blast of air coming from the gap between the fender and the cab. I am very confident that these fans are moving at least as much air as the factory fan did, especially in the configuration I had it in. On to the road test. I was disappointed! Why? Because the frickin' fans never needed to come on, that's why! This was uncharted territory for me, and it turns out that these trucks cool so well with no load, that just moving through the air is cooling enough. I had to make the fans come on, and this was when it was 95 degrees out. We stopped for ice cream, and I shut the truck off, and put the fans on. I wanted to see how they blew the heat around, and with my fiberglass hood, it's nice to take some of that radiant radiator heat out and disperse it. A strong wind of hot air was blowing across the ground, and I could tell these fans were taking the radiator temp and reducing it pretty fast. In only a minute or so, there was only a mild warmth that I could feel. So, at this point, I obviously have no hard data as to how well this setup will work going over a big mountain with a load in tow, but I feel pretty confident that it is going to work great. The next big test will be hauling the Moose Tail out to the IDI Weekend in just a few weeks.

 

[Darrin Tosh]

Nice job as usual Mel! Real nice pair,..congrats on getting it done. Did you notice any power difference with no fan on the truck?

 

[flatlander]

I like the compressed hose. A little vibration dampener as a bonus, eh?

Oh, and I found out that your radiator is only used on manual trans, no a/c trucks. I have one from the bucket truck that I cannibalized. I needed a lower radiator hose and no one stocks it. Also mine is complete crap (the radiator) so if you'd like an extra lower hose it's all yours.

 

[Devilish]

Umm, very impressive pairs

 

[argve]

Holy Snickles Batman lookie at those!

Nice install Mel - Sure wish I could see them in person this year. Oh well there's always next year.

 

[lotzagoodstuff]

Cool : literally!

Nice work Mel. Those Taurus fans are very popular with the 5 Liter Mustang croud, I am betting that two of them move gobs of air. Do you keep track of what you get on a tank of fuel? I would really like know how much fuel mileage you pick up. There is always this question about how much more drag you get from your alternator pulling more current, but I say based on your initial feedback you won't be pulling any current when they aren't running. I am guessing you'll see +1 mpg (which by the way is about ten bucks a tank these days, which falls into Justin's mileage improvement thread). If you see +1 or better, I'm pretty sure I'll be duplicating this mod on my rig.

Great write up, details, photos: pretend you're a politician and vote yourself a raise !

R. J.

 

[Russ]

Nice pair... will we get to see them twirl at the Rally?

 

[lotzagoodstuff]

By the way: what did you use for a thermal controller/relay to turn them on and off?

 

[Mike]

Sorry for the 2 parter. Never knew your limited to 15 photos per post here. If you missed part 1, it's here.

I merged the two threads together so all the info can be found in one place Mel.

Out of curiosity have you looked over geo's electric fan conversion thread he did on the 96 PSD?

 

[Agnem]

Ah, wonderfull. Much better. Thanks much. As for Geo's article, yes I used that as my inspiration for the project. I had hoped to avoid the messy fiberglass aspect though, and by using Taurus instead of Windstar fans, I was able to accomplish that. Someone asked about the electricals, I have to sheepishly confess that that part is not completely done yet, because one of the parts I needed from Summit is back ordered. What it's finished, it should look like this...

There will be a 1-3/4" upper radiator hose adapter that will hold two temperature switches. One that turns on at 185 degrees, and one that turns on at 200 degrees. The 185 will feed a SPST relay that when energized, will feed the hinge of a SPDT relay. That relay in the rest position, will route the power to the low speed fans. That relay will also be driven by the 200 degree switch. When engergized, it will direct power away from the low speed fans, and instead route it to the high speed fans. It's important that the Taurus fans not be feed both low and high speed at the same time. So the logic is 185 on, low speed. 185 and 200 on, high speed. The 200 would never be on by itself, unless the 185 failed, in which case there would be no fan. I can live with this level of reliability, as I may configure the low speed to work off a switch in the cab, so I can run the fans manually if needed. In total, their are 2 relays and 2 power contactors (starter solenoids) in the circuit. It will be interesting to see what it does to my fuel milage, but unfortunately it will take quite some time to accumlate that data, as I plan to replace my DPS injectors with stock ones, and I'll be towing a good bit coming to the rally. The all time high I ever got with the Moose Truck was 23MPG. I'll see if I ever beat that some day.

 

[geonc]

Ah, wonderfull. Much better. Thanks much. As for Geo's article, yes I used that as my inspiration for the project. I had hoped to avoid the messy fiberglass aspect though, and by using Taurus instead of Windstar fans, I was able to accomplish that.

Looks real Mel! I'm happy to have been an inspiration
Mine was done primarily for the OBS style but the basics are there.

Those fans DO move a huge amount of air!

Great job and forethought Mel

The twins do look good