Performance Electric Radiator Fan Options

[yossarian19]

I partially agree with this. As I understand it, fan blade design affects the efficiency of the fan as a system to move air, that is true, HOWEVER it does not allow for the fan system to do more work than the energy it takes from the engine. No blade design can make a fan do more work, it can only increase the system efficiency thus allowing the fan to not waste as much of the energy being used to turn it.

1 HP is around 700+ watts...and some of these fans are 80 watt (like the DBO fans).

In the electric/electric comparison, the motor will not be able to do more work because of a more efficient fan blade...the more efficient fan blade will actually have to spin slower than the inefficient fan making the air moved equivalent. Regardless of the rpm the fan blades are smashing into air molecules and it requires work to move the air. More air pushed, more work done, more amps drawn (or higher voltage used).

Ultimately there is a theoretical maximum amount of air that can be moved by a 100% efficient fan motor and 100% efficient fan blade at a certain wattage. I DO agree that replacing a 50% efficient fan blade with a 75% efficient fan blade on the same motor will move more air while using the same amount of power...but it's only because it is losing less...which I guess is more or less what you said, Yossarian.

Jeez I can say a lot without saying much of anything, lol.

Yeah, we agree.

 

[Digger87xj]

Derale fans installed. I'm impressed. These fans move serious air! I believe the 4000 cfm rating.

Didn't cure my hot-up-hill problem BUT they really cool it back down in a very short time unlike the dirtbound fans.

A bit of a challenge to fit. trimming of the shroud was needed to fit over the steering box, and a small amount still sits above the upper rad support but the hood closes nicely.

fully recommended for those who are not afraid of a little fab work to fit them in.

 

[Redsnake]

Derale fans installed. I'm impressed. These fans move serious air! I believe the 4000 cfm rating.

Didn't cure my hot-up-hill problem BUT they really cool it back down in a very short time unlike the dirtbound fans.

A bit of a challenge to fit. trimming of the shroud was needed to fit over the steering box, and a small amount still sits above the upper rad support but the hood closes nicely.

fully recommended for those who are not afraid of a little fab work to fit them in.

Any pics? Curious to see how they fit compared to the Dirtbound fans. Are they wired to come on at different temps or together? Just curious how this compares....

 

[Digger87xj]

no pics. no comparison with the dirtbound. the dirtbound fit with no modification.

the derale fans are essentially too big to be considered a nice fit to the xj radiator, and are not as wide as the radiator.

The dirtbound fans are rated 4300 cfm avg ... IMHO it's bullpucky. If they pull 4300 then the derale pull 6000.

The Derale fans come unwired and with 2 relay kits.

I used 2 hayden adjustable fan controllers with the inserts that go into the radiator fins. I set them up to come on at different temps and also both on with A/C

 

[Redsnake]

I'm currently running the DB triple fan kit and an FFdynamics 2-core aluminum radiator... Also have hood vents to help allow the heat out of my '01 when in slow traffic or idling... and so far so good.

Although w/the temps climbing my rig has been running about 10-15 degrees hotter during the 95+ degree days over when it was cooler out. According to my temp gauge, I normally run ~ 195'ish and lately it's bumped up to 210'ish... if that makes sense. But cools down nicely once I start driving or get out of bumper/bumper traffic. I'm also running my 3 fans on 3 separate turn-on temps... 185, 205 and the 3rd fan is wired directly into my OE Electric fan controller. So I 'think' it's w/the temps raise to 217 and the AC is on. So far my 3rd fan has rarely come on and if so, it's only momentarily.

 

[USMCGunrock]

I'm currently running the DB triple fan kit and an FFdynamics 2-core aluminum radiator... Also have hood vents to help allow the heat out of my '01 when in slow traffic or idling... and so far so good.

I installed the FFDynamics rad and the 3 9" fans w/o shroud about a month ago. This weekend I replaced the t-stat with Mopar stat, housing and water pump. Comparing the new setup from the stock...the stock mech fan I think moves way more air than the 3 e-fans. My xj also has louvers and with the mech fan you can feel air being blown out of it...now with the e-fans could barely feel any it other than just heat escaping and you can only feel air getting blown right on the bottom of the engine. With the stock setup my temp gauge never went past the 210* mark. With the FFD e-fans having it the first week and with outside temp of 88*, stuck in traffic for 20 minutes, it went over the 220* mark. Today we hit 95* for the first time and my gauge was on the red after being in traffic for over 40 minutes! As soon as I started driving and going over 50 mph the temp went back to 210*. Will be ordering the DB 10" shroud and getting some 10" fans for it. Hopefully I can get it in time and install it this weekend.

 

[Redsnake]

I do think the OE Mechanical fan pulls more air than the Dirtbound setup, but the DB 10" fans w the shroud is better than the FFD 9" fans.

I'm interested to see how the DB compares to the FFD fans once you do the install. I have kept all my mechanical fan/shroud/pulley bolts, etc just in case this Summer proves too much for my DB setup.

 

[USMCGunrock]

I do think the OE Mechanical fan pulls more air than the Dirtbound setup, but the DB 10" fans w the shroud is better than the FFD 9" fans.

I'm interested to see how the DB compares to the FFD fans once you do the install. I have kept all my mechanical fan/shroud/pulley bolts, etc just in case this Summer proves too much for my DB setup.

I think you are correct, just that I ordered the FFD without thinking too much since my rad started leaking badly and needed replacement. I ordered without really doing much research since my xj is my daily driver. Will post as soon as get this taken cared of.

 

[Ronbo]

Didn't cure my hot-up-hill problem...

I was in the same situation and looked at everything. Radiator, trans cooler, trans, fans, fluids, hoses, belt, belt tension, etc. Turned out to be the water pump. Nothing physically looked wrong with any part of it. I replaced it with a quality Napa pump and instantly fixed the problem.

 

[Weasel]

Well I went ahead and ordered the Derale 16928 high output fans from Jegs...

Derale#259-16928

I had these on my Jeep. They pull a ton of air. Sounds like a jet turbine spooling up. However I took them off. I was running a stockish radiator and just didn't have enough room between the radiator and engine. The shaft the fans spin on was rubbing the radiator and causing some issues.

This is them installed

Had to do alot of cutting on the shroud:

This is what I ended up with for engine clearance:

It cooled the Jeep pretty well. If they were slightly smaller I probably would have left them but I didn't like using the stock style junk radiator and wanted something better.

I went with a Griffen radiator and based on the dimensions the Derale fans would simply not fit. I ended up moving the Griffen radiator forward a 1-1.25". If your current radiator is fine moving it ahead would give quite a bit more clearance with the Derale setup.

So I ended up with the FFDynamics 3 fan setup:
https://plus.google.com/photos/117016052099699625203/albums/5699140328190416609?authkey=CL-U9ZfssMvrwwE

It works fine last year in the hot canyons running the AC. Now I'm thinking the extra heat from pulling a long hill is due to the transmission. Mine is cooler through my radiator, I have a gauge on the trans temps and for the longest time I thought I had it wired wrong as it would not ever move on the gauge. I redid it several times and finally gave up. Needle never moved until I hit one of our hills going wheeling and the temp rose pretty quickly and the engine temps followed. Flipped the 3rd fan on it and it held temp.

CFM wise I don't know what the FFD actually is. Just due to the smaller size they can't match the Derale, separately but with all 3 it's close. About the only specs I really believe are what Spal rates their fans at. It's really tough to get decent CFMs from any of the smaller fans.

For water pumps I run a Hesco unit. Only pump I will use. I went through 3 Napa premium (or whatever the top of the line is) in 4 months. Bought a Hesco and it ran for 5 years and then sold it to a local guy and he's had it for 2.

 

[kastein]

I need to look into those Derale fans.

Maybe the DBO fan kit was measured for airflow without a radiator present, or with a radiator with a more open fin design, vs the Derale set? That would be my guess as to why it has a higher rating than people are seeing.

You just reminded me...the Japanese 2J from an Aristo has a hydraulic pump. I replaced it with a US pump and now it's belt driven. I have one in the garage. I will investigate this further. Ha.

Are you thinking what I think you're thinking? WJs have a hydraulic fan...

 

[child9]

It might also be noted what temp those CFM readings were taken at. The air being pulled through a hradworking radiator and fan setup can get pretty hot, and the hotter it is the thinner the air is. This must affect the real world flow vs. bench testing.

It's been suspected above, but I GUARANTEE the OEM mechanical fan pulls more air. It is literally using amounts of energy we can measure in HP. One hp is approx 745 watts! If your fan is using even one HP, then it can move as much air as 9 electric 80 watt fans.

 

[Weasel]

engine HP doesn't translate into Electric fan efficiency. I don't feel the mech fan pulls anymore then the setup I have does. Also fans are rated in Amps not watts. Divide by 12/13/14 to get the amps. However I still don't think that is an sort of direct correlation.

 

[child9]

Fans are not rated in watts? P=IR, as you sort of pointed out. Feel free to convert to whichever unit you prefer, I guess. My fans are rated with voltage and watts.

You are correct, power doesn't just translate into efficiency. Power translates into energy and energy translates into work done. Efficiency is a measure of how much work is effectively done by a system that is given a certain amount of energy. A mech fan blade could only be 50% efficient and still move a ton more air than our little electrics if it is actually using 1 HP. I'm not making this up or sharing an opinion...it's physics. The math is simple...no need to take an integral or model the system with a differential equation...just add and subtract, divide and multiply. Easy-breezy.

Anyway it's not especially relevant to the thread since this is about comparing electric fans with other electric fans...so I'm done explaining the mumbo jumbo. My time might be better spent looking for my hydraulic water pump, lol.

 

[hubs97xj]

The stock electric fans draw 15 to 20 amps each. I can not seem to find a consistent number on stock fans probably due to tests on worn motors and the different replacement brands.

Alternators do use some horsepower to run, but it is much less compared to a mechanical fan. If removing the mechanical fan gains 10HP, but adds 5HP of load to the alternator there is still a 5HP gain.

This formula I found says that a Cherokee's 90 amp stock alternator should require about 1.93 horsepower to turn at the amperage load.

I used a clamp-on Fluke the other day, and saw 30A at startup, and 11A when running. This is on my OE aux fan; the later style with curved blades. There is a possibility I didn't measure correctly, as I've never used this meter before, but I believe this is pretty close. I intend to check again when I've gotten a little more familiar with it.

For limited comparison, my 14" ProComp fan pulls ~9A running on high (rated around 2200 CFM, which I assume is its max while completely unobstructed. ). I couldn't get what I believed to be a consistent current draw on startup, due (I think...) to the variable speed controller.

I just replaced the Procomp about a week ago. I got 5 years of use out of the first one, so I figured I'd try it again since they're relatively cheap, and I lacked the time/resources to build/buy something better. Still on the original aux fan, and I'd be running two of those, like Gradon's setup, if I could more easily fabricate a few pieces to do so.

JMO.

 

[USMCGunrock]

So I had the FFD radiator with 3 electric fans without the shroud and new water pump and thermostat for three weeks (6/22/13 - 7/14/13). The FFD setup worked well, kept my temp at about 210* at an average of outside temp of 85-90* here in the NY/NJ. But as soon as I turned my AC on within 5 minutes my truck overheats. My truck is a DD with hood louvers and external trans cooler in front of the rad. It takes me 30 minutes going to work in the morning and from 1.5 hrs to 2 hrs in traffic on the way home driving about 25 miles one way. When I need it the most, being stuck for about 30-45 minutes on a 3 mile stretch, I'm cooking in my truck!
I decided to order the DBO shroud for 10" fans and 3 10" fans to see if it will perform better but it took the DBO shroud 2 weeks to get to me. I finally got it installed Saturday (7/13/13) and what a big difference! When I first got it installed I let my truck run curb side for about 45 minutes with AC full blast. The temp needle only went up to the "1" on the 210*. Yesterday was the real test and a good one too since it was about 95* out feeling around 98*. With the AC on and stop and go traffic (1:45 hrs) my temp gauge needle only went as far as the first quarter of the "0" on the 210* mark. When I finally got up to speed of about 60 mph on the last 20 minutes of my commute, my temp went below the 210* mark.
One thing to add, my trans fluid is getting cooled by the external B&M trans cooler and not going through the radiator since I had some fitment issues with the FFD supplied rad trans line fitting.
My final thoughts...I've only had the DBO with 10" fans for a couple of days. This whole week we are having a heat wave (95*+) so it will be a test to see how this makes out. I don't have any clearance issues between the fan with shroud and the mech fan pulley but had to cut a notch on the rad support so that it can go over the DBO shroud and clear the radiator fill port. I still think that the mech fan pulls in more air but that's coming from one half of the radiator, now I have 3 fans and that's been distributed by 3rd. Last year I still had some overheating issues with the mech/electric fans overheating. I can't give CFM comparisons since I don't have the equipment to even measure it..lol

I will update again end of this week to show how the fans held up.

 

[Weasel]

You need to have a shroud of some sort, otherwise you are loosing alot of air flow. Are you selling the FFD fan's?

I have the equipment to get some airflow readings but it's going to be a couple weeks before my jeep is running again.

 

[child9]

^+1 GOTTA have a shroud. Path of least resistance and all that.

 

[Aggie_Cobra]

In my thinking, the best reason for moving away from an engine driven accessory to an electric driven accessory is that an engine operates over a wide RPM range, while the accessory has an ideal speed that is usually not going to correspond with the given engine speed. The issue isn't how much power a fan draws from the engine at 2000 rpm, but how much power it draws at 5000 rpm, when you need power the most, and the fan is out of its ideal speed.

 

[RAVC1]

All,

Thanks for this thread! The issues I have been experiencing with my '88 Xj needed this.

A few weeks ago I found my electric aux fan was not coming on as designed with regard to the radiator fan switch. I have tested & returned (4) new radiator fan temperature switches including (2) OE from a dealer in LA. The closing temps for these have been: 212F, 208F, 206F and 204F. With a spec of 190F these are clearly flawed. Yes, AMC or Chrysler made a serious mistake when they located this switch just above the radiator outlet hose port, but this has nothing to do with designing a temp switch correctly! Apparently, no one wants to do this correctly these days. I intend to purchase the NAPA ECH FS166 next, but I must evaluate the fan controllers simultaneously because, even the ECH FS166 features a 20F degree window for closing. However, these also feature a 3 yr warranty. I refuse to purchase another inferior radiator fan switch. Many of the Renix vintage members have offered excellent help, but these switch issues irritate me. Design and manufacture the damn part correctly!

At the moment I have temporarily disconnected the fog light connection and I hard wired this to the fan switch circuit so I have manual control of my aux electric fan. With 100F heat index temps here in MI I did this just in time.

However, I considered the Derale 16926 earlier today to replace my OE electric fan. This can be combined with the Derale 16749 fan controller with a variable turn-on temp of 150F-240F. I will be watching this thread closely. At the same time I must heed the proper operating temp for the 4.0L. My cooling system clearly features a low-T thermostat in that I usually run at 170F-175F and must respect the fact that this might be too low for the 4.0L engine operating T.

Additionally, it seems easy to criticize a single-row radiator for this system. What the heck was AMC thinking? I will readily admit it seems to work, but single-row? In turn, this has me thinking of the CSF 3-row radiator, but this has issues with install because, it is so much thicker. Maybe the FFDynamics 2-row radiator. Regardless, the idea being that passive cooling improvements should certainly be employed too right? I am also concerned regarding the smaller size of the coolant passages in these new radiators so, I'll probably call Griffin too because, they have been in this business for a long period of time.

Rick