01yellerCobra
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Has anyone that tows swapped to an electric fan? If so, which fan did you go with. I have an electric fan sitting in the garage, but I doubt it would work in the truck.
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Thought about it too, but can tell you that I towed this monster around to/from the East to West Coast and in between fully loaded many times w/ no probs.
Not pictured is my roof-mounted air deflector & the Nose Cone was a great addition to divert the air from that massive surface area.
yeller, the big thing to keep in mind when looking at an e-fan setup is the CFM of air that the fan will pull. The magic number you need to be looking at is 3,000 total (assuming you are running 2 fans or 1 large one). Getting less than 3,000 and you are asking for problems. You can go with more air flow, but what you will find is that it will be a big draw on your electrical system. So, however you want to do that.
I am one of those that has switched over to an e-fan setup. I used it when towing a car trailer with a 73 El Camino on it. Never saw the temp needle move.

If you ever had this happen you know it because it sounds like a 747 as you give it gas!! That's interesting tom. Especially coming from an electric fan manufacturer.
I did some research and found out the Mark VIII fan I picked up for the Cobra is rated between 4500 and 5000 cfm. I like having the e-fan on the Cobra. I've changed the on/off points in the tune. And it's never had an issue. Even using the A/C in Arizona in the middle of summer.
Might have to take some measurements and see where my thoughts take me.
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It would be nice if this could be done on the expy. I have seen the option in the expy software but dont know that the hardware supports it. Where is the control wire or driver for fan relay?? I assume the cobra came with electric fan?!
Are you running an electric fan? I don't think I'll tow something that big. But I do know the wife is starting to wonder where we could store a toy box.
Ok, i am going to toss in my 2 cents on the subject and some of the "thermo-knowledge" as I see it and for others to ponder. First off, making the assumption that both an e-fan and a mechanical fan pull the same amount of air, one would assume that it takes the same amount of air. In reality, it takes a different amount of air. Not following you here unless you are stating different fans have different CFM's flow capacity. No argument there. Like the article somewhat states, the e-fan is more efficient (ie, takes less power). Why is that? Simple, the e-fan spins at 1 speed where the mechanical fan has to operate over a much larger range. If you want to test me, it is simple. With the motor ice cold (which should have the mechanical fan in a free spinning condition), open the hood and then start the motor. Now, rev the motor slightly and listen to the mechanical fan change speed and feel the amount of air the "free spinning" fan is blowing. The article may have stated that Moving any amount of air requires a finite amount of power (basic laws of physics). Where, in an e-fan setup, the fans do not move at all because the switch is not made up Bingo!!(assuming a properly designed system, if you need help, let me know). So, even with the motor ice cold, some amount of power is being taken from the engine to move the air. How much power is being used, like the article said, only the manufacturer knows truely. The numbers I have seen is in the 6-8 hp range from a 4.6L mustang article about e-fans. This is more realistic!!
Another advantage that I will put in here is that e-fans will allow the motor to warm up faster because like you could have proved, the mechanical fan is still pulling some air through the radiator. The thermostat doesn't "pop" open once it hits a magical temp, it slowly opens over a temperature range. So, as you start getting close to the desired temp (within about 40 degrees or so), the thermostat starts letting some of the warmer water through the radiator, which is then cooled slightly by the mechanical fan, removing heat, and slowing how fast the motor heats up. The e-fan is still sitting there, not turning since it has not reached its turn on point (if properly set up).
Like the article somewhat talks about, if you put the two fans on equal terms (same air flow), the e-fan is going to require less power because:
1) the fan is enclosed in a hoop around the fan blades, (some not all) preventing air from being discharged out the blade tips, not being effectively used and actually can be sucked back in to be pushed by the blades multiple times
2) the blades of the e-fan only spin at 1 speed, so, therefore can be more finely tuned to pull the maximum amount of air using the least amount of power.
Low rotating mass design due to limited rpm range. Mechanical fan has to be much beefier due to the volume of air necessary at idle and the relatively low rpm of the motor and of course the large rpm range. There is also much tighter clearance to radiator and shroud with electric which cannot be done with mechanical due to engine movement.
Like a lot of you have said, the stock fan does what you need, so why change it. I tend to agree with this point. But, at the same time, I also have to pose a question: If mechanical fans are "more efficient", then why are all manufacturers (even semi's now) switching over to e-fans in an attempt to make better mileage? Just some food for thought.
Not sure where it was mentioned that mechanical fans are more efficient. Let me make it clear I do not believe this. Maybe your refering to the article where it spoke about the inefficiency of converting mechanical energy to electric back to mechanical. This is simple physics but the loss is far less than the gain. Electric will still be more efficient...properly designed of course. This is why I said feel there is some truth to it not that I agree with it. I would also point out that much of the electic fans are installed in most vehicles now is due to easier packaging and tighter clearances. The reason why front wheel drives have always had electric fans..... So I would not assume fuel milage is the sole reason a manufacture chose to do it.
If you have some of your own ideas, please put them out there and I will toss around some ideas that I have. Please note that I am a firm believer in the gains are not great when doing the switch from a mechanical fan to an e-fan. But, at the same time, I know working on my truck after the e-fan mod has become tons easier because I now have 8" of clearance between my fans and the motor. I sit on the radiator, stick my feet down in front of the motor and I lean in a little bit to work on the motor. Makes things so nice if for no other reason.


