Performance Electric Radiator Fan Options

We started filling Franks Vortec thread with this, so I thought it appropriate to move the discussion to it's own thread.

The issues myself and others are having seem to be a combination of fan quality issues as well as advertised CFM discrepancies.

My situation is that I run the Dirtbound 3 fan setup, and in only a few months I've had 2 of the 3 provided fans fail due to blade breakage. I had a spare 10" fan blade that I swapped onto the motor that came with the cooling shroud and kit, but bought an ebay $20 replacement fan when the second fan blade turned up broken. Running two fans let my turbo 3.0L run a bit hot, though it normalized and stopped climbing and thus didn't actually overheat. This only occurred once I got in traffic on hot days and everything got proper heat soak. There is a noticeable difference between the through-flow of the dirtbound provided motors vs. the super cheap ebay fan motor, so the ebay setup is insufficient, temporary, and I am on the hunt for decent fans.

I found these and plan on giving them a try.

http://www.the-fan-man.com/shop/siz...th=33&osCsid=fc46a057be13124b290819103da627b3

I for one would be interested to hear from others what fan solutions they have used successfully for long lengths of time.

10" low-profile radiator cooling fans are the issue here. Thanks!

The fans you posted look identical to the 12" ones I have on my griffin radiator.

They pull some SERIOUS CFM.

I have been using the dirtbound kit in my current rig and haven't had any real problems. So far with the ac on in 100* in city stop and go traffic it topped out at 220. I know that the trans was a contributing factor as it is very tired at 245k. I'll be pulling the auto soon and I expect the temps to not get as high once completed. I haven had any problems with the blades breaking. The cfm claims of this system seem a little exaggerated although it does seem adequate.

I ran the ffdynamics system non shroud in my other rig. It worked ok when it worked but the temp probe thing was very finicky. I like dirtbound inline pickup and preset modul.

I've been running the Dirtboung triple fan rig since ~ 12/2012 w/no problems (knock on wood).

Also running clean coolant, 195 HD thermosat, Fluiddynamics 2-core aluminum radiator, Napa water pump ... and I have the 3rd fan wired into my OE Electric fan (so it only runs when the AC is on an temps get above 220 ... I think... only ran 1 or 2 times briefly). Also I have a set of hood vents which help when in stop/go city traffic.

So far so good. I can't remember, but doesn't dirtbound warrant his fans for a while? I'd assume the fan's braking would be covered for a bit, but I'm not sure.

I have been running these http://www.summitracing.com/search?keyword=DER-16928&dds=1 since early 2004 and I am quite happy with them. They are a bit power hungry which required a higher amp alternator and relay/s to satisfy their appetite for AMPS. One fan shroud required some messaging to fit near the steering gear.

What is the most common reason to "upgrade" to a fan/radiator set up that still warms the engine to warmer then the recommended operating temperature?
I have a completely stock cooling setup and my jeep never gets above normal In 125 degree weather, In traffic with AC on high..

Just curious

bluejeepkid said:

What is the most common reason to "upgrade" to a fan/radiator set up that still warms the engine to warmer then the recommended operating temperature?
I have a completely stock cooling setup and my jeep never gets above normal In 125 degree weather, In traffic with AC on high..

Just curious

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Not sure where you are getting that they allow the engine to get hotter. The hottest the engine in my MJ with the Dirtbound setup has gone to is 210F which is perfect.

One of the reasons for going to an electric fan is to gain back the horsepower lost from spinning the heavy mechanic fan.

I'm upgrading because the turbo 3.0L produces more heat and the Jeep system is taxed. Also the stock fan shroud didn't match the 2J fan location, so I had no choice.

I currently have the DBO 3-fan kit, stock 4.0L for meow. Stays cool. On occasion when going up decent grade hills under load starts to get warm. But most likely due to trans heating up more than normal.
Even on hot days @ the dunes stays below 210. Sometimes the needle pops right over the middle but cools right down.
The fan motors are good, haven't had any issues with the fans themselves. The fan shroud is great, fits nicely.

Alexia said:

Not sure where you are getting that they allow the engine to get hotter. The hottest the engine in my MJ with the Dirtbound setup has gone to is 210F which is perfect.

One of the reasons for going to an electric fan is to gain back the horsepower lost from spinning the heavy mechanic fan.

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The correct way to state this, is that you FREE up horsepower by removing the mech fan load.

I can't speak for automatics or turbos, but: 2 STOCK 97+ 10-BLADE E-FANS.

Johnnie Walker said:

The correct way to state this, is that you FREE up horsepower by removing the mech fan load.

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You just said the same thing.

:doh:

I have gone through various fan setups and spent a crapload of money in search of proper cooling from electric fans. What I have settled on is 2 10" Spal fans from the supplier you linked to and a smaller fan that came from FFD. I plan to replace the FFD fan with a Spal as soon as I can afford it because I have had several of the FFD fans fail on me. I have yet to find anything better than Spal fans. They are expensive but they flat out work. There is no other fan I have tried ( I have tried about 6 different brands) that even comes close to the CFM of a Spal fan. It is also critical to have a high enough capacity relay for the fans or separate relays for each fan. The Fan Man had the best prices I found. Good luck!

bluejeepkid said:

What is the most common reason to "upgrade" to a fan/radiator set up that still warms the engine to warmer then the recommended operating temperature?
I have a completely stock cooling setup and my jeep never gets above normal In 125 degree weather, In traffic with AC on high..

Just curious

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I have a 5.9 V8.. can't install a mech fan with out re-engineering the front end.

techno1154 said:

I have been running these http://www.summitracing.com/search?keyword=DER-16928&dds=1 since early 2004 and I am quite happy with them. They are a bit power hungry which required a higher amp alternator and relay/s to satisfy their appetite for AMPS. One fan shroud required some messaging to fit near the steering gear.

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Amp Draw: 50.00 amps

Boy howdy you are not kidding. But I believe the 4000 cfm rating is true too..

Now I want to figure out how much HP it takes to generate 150 amps (50 x3) and compare that to the HP used to turn the mechanical fan. I am almost willing to bet we aren't saving much if anything according to Lenz's Law. All that current requires more HP since more current required = more current generated = higher internal resistance... there is more work (in the mathematical sense) that must be done to spin the alternator and that takes power.

Only possibility I see is that the electric motors are a lot more efficient than the gasoline engine, but the power used by the motors has to be generated by the inefficient gas/alternator combo first, so I doubt the savings. It likely varies from fan to fan and setup to setup. Either way I don't envision a LOT of gains in any setup from going electric. I just have no choice.

Those derale fans are 25a each, and come as a pair in a dual shroud, so hence the 50a total draw, for 4000 cfm

The spal fans draw 10a, x3 = 30a. for 3000 cfm

child9 said:

Now I want to figure out how much HP it takes to generate 150 amps (50 x3) and compare that to the HP used to turn the mechanical fan. I am almost willing to bet we aren't saving much if anything according to Lenz's Law. All that current requires more HP since more current required = more current generated = higher internal resistance... there is more work (in the mathematical sense) that must be done to spin the alternator and that takes power.

Only possibility I see is that the electric motors are a lot more efficient than the gasoline engine, but the power used by the motors has to be generated by the inefficient gas/alternator combo first, so I doubt the savings. It likely varies from fan to fan and setup to setup. Either way I don't envision a LOT of gains in any setup from going electric. I just have no choice.

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Agreed, you are losing power, BUT remeber that a Mech fan turns all the time, even with a fan clutch, while an electric fan doesn't turn unless needed.

bigdaddyjlove said:

Agreed, you are losing power, BUT remeber that a Mech fan turns all the time, even with a fan clutch, while an electric fan doesn't turn unless needed.

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Yep, so basically if you are doing 30mph+ and it is not ridiculously hot outside then those fans will be sitting idle.

The Dirtbound Offroad kit draws 18 amps with all three fans running. 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.

Alexia said:

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..

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Moving a lot of air takes a lot of power.
Claims of lost or gained horsepower are just that, claims, unless there is a dynamometer available for before and after measurements. I don't know of any other way you could measure the actual engine horsepower
consumed running the mechanical fan (plus the stock electric fan) vs. an all electric setup. Numbers taken off any internet sit are suspect. Butt dyno claims are to be ignored.
Anyone have actual dyno measurements? Dr Dyno maybe?

lazyxj said:

Moving a lot of air takes a lot of power.
Claims of lost or gained horsepower are just that, claims, unless there is a dynamometer available for before and after measurements. I don't know of any other way you could measure the actual engine horsepower
consumed running the mechanical fan (plus the stock electric fan) vs. an all electric setup. Numbers taken off any internet sit are suspect. Butt dyno claims are to be ignored.
Anyone have actual dyno measurements? Dr Dyno maybe?

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It is fairly well known the mechanical fans add rotational mass and drag to the engine
http://www.carcraft.com/howto/ccrp_0707_high_performance_cooling_system/viewall.html

While this may seem trivial, dyno testing in the May '00 issue of Car Craft resulted in losses of 35 hp at peak horsepower from a simple one-piece, plastic, engine-driven fan.

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