Yeah, I imagine it would be a bit harder to come up with those numbers without also stating the engine RPM.

What's your reason for that?

 

Don't see the point to adding another complex system, and electrical load, for very little, if any, return. In something with a longitudinal orientation, like most RWD platforms, where the accessory drive is right there facing the radiator, I don't see any *good* reason to be adding electric fans.

If you're having overheating issues at low speeds, sure, electric fans can correct for that, by being able to push more air than a mechanical at low rpm, but I consider that a band-aid for other issues.

On something that I was purely going racing with, I might consider electrics, for that little extra bit of horsepower that spinning a mechanical fan uses, but on a street rig? Nope.

In my experience, *most* (not all, actually read the words I'm saying) cooling issues with mechanical fans have to do with the shroud being broken, or not there at all, or there not being sufficient air direction between the radiator and the grill, to keep the air flowing through the radiator.

I've *done* electric fans on RWD things, but only in cases where the packaging of a mechanical fan would just be problematic.

 

I am with you brother

I just love the posts that say they have an over heating problem and about 20 posts in you find this started after they installed electric fans, the factory system was working great up to that point so why change
Dave ----

 

I like simple things. My hotrod has carbs and an electric fuel pump. I don't *like* that, but the 302 in it is a later EFI model, that didn't have the timing cover provision for a fuel pump, so I didn't have much choice. Although I am currently correcting that.

The electric pump worked fine, but it was an extra electrical system, with more potential points of failure, that just frankly, aren't necessary. I got myself an earlier timing cover, and a fuel pump eccentric, and a quality mechanical fuel pump.

I don't have any *problem* with people that want to do swaps to things like electric fuel pumps, or electric fans, I just think that it's important to ask yourself *why*. If your only answer is "because somebody said it's better" or "because mechanical is old and busted, and new cars are all electric stuff" you're probably better off spending your money on something else, because you're attempting to solve problems that don't exist. People can do what they want, but I'm not going to be the guy recommending people do non-sensical things.

 

Understandable.

I think part of it is modernization. It's not that the older system doesn't work, but there's a reason systems get updated. There's reasons we don't use carbs anymore, mechanical fans, mechanical pumps, etc. etc.
So, even though I like to keep things simple where I can, I also like to update and modernize. This is a daily driver, and not a weekend toy, or a farm truck where it doesn't matter. I drive it all the time, do long distance trips, take it off road, etc. So I want to see what the best options are. And so I do the research on whether or not it's worth it.
If it's not worth it, it's not worth it!

For me, one of the places an electric fan would come in handy is off-roading. There's been plenty of times I've been out on some pretty serious back roads. My engine's working hard, it's 100° out, and I'm only moving 2 - 3mph in low range. There's not a lot of air flow and even though my engine doesn't overheat, it gets pretty hot.
And I also like the idea of freeing up horsepower and gaining gas mileage. Might not be a lot, but every little bit helps.

 

They dont use mechanical fans in todays cars as the motor sits sideways so they would have to put the radiator on the side also and there is no room.
Same reason they went with serp. belts, everything gets installed as far back on the motor to give room to the fender wells.

Now I do under stand on needing the electric fans when off roading as I have seen the temp go up but never to the point I was worried it was going to boil over.

As for saved horse power, the way I see it all you did was trade the mechanical fan to now run a large out put ALT.
It still takes HP to turn it to put back or maintain what the fans are using.
I would like to see a test that shows what HP is saved running the Elec. fans over the mechanical fan.
I know they have posted what the mechanical uses but never seen what a larger out put ALT uses to run them fans.

Thats just me and the way I feel good to hear it is working for you and others but I think its because you have done your home work.
Dave ----

 

That makes sense on transverse engines. The rotation of the engine isn't facing the radiator. I didn't think of that.

Serpentines are a little different as they even had those on the 300. From my understanding, that was done for a bigger, fatter belt with more surface area, which allowed them to run components that required more oomph (like a high amp alternator). I know when I installed a 130 amp alternator in my Bronco, I had to modify the belt arrangement a bit so that I could use two belts on the alternator, along with my power steering and A/C. One v-belt on the big alternator would squeal.

As far as I understand it, the e-fan gets better mileage on the open road because it's not spinning at all at those speeds. A mechanical fan spins no matter what. So, the load on the engine with an e-fan is on par with a mechanical fan in stop and go traffic, etc. but on the highway, the e-fan is using 0 because it only comes on on occasion, whereas the mechanical fan is on 100% of the time. A clutched fan never goes to zero, as I understand it. Just "less".

 

No, you're correct, a mechanical fan, even a clutched one, unless it's got an electric or air disconnect, like some Big Diesels, is always turning. It's always using some portion of engine power to turn. And serpentine belt setups are just more robust, no two ways about it. My hotrod runs carburetors, but it's got the later EFI serpentine setup, and there's no way I'd switch it back to V-belts unless I had good reason to.

The *only* place I prefer V-belts to serpentine, is if I'm offroading with water crossings, as it's *really* easy to just pull the fan belt off, drive across the deep water, and then put the belt back on on the other side. Otherwise, *zero* advantage, as long as you keep up on the belt/tensioner change intervals.

My issue with the Electric fan swap, under the guise of "efficiency" and "mileage savings" on something like an F-Series, is really simple. It's math. Just for the sake of argument, lets say that you've got an F150, that gets 17mpg going down the highway with an otherwise functioning cooling system, with the Mechanical fan. Just to pick a number out of my butt, lets say it has a fuel capacity of 19 gallons. Right now, around here, a gallon of unleaded is running roughly $3.75,

so 19 x 17 = 323 miles 19 x 3.75 = $71.25 to fill from empty, $71.25 / 323 = $0.22 per mile to drive the truck (remember, this is a very basic calculation, I understand it's not that simple)

Let say that you do an electric fan swap, and you manage to do it on the cheap, for lets say $75 on wrecking yard parts (which actually sounds a little low to me, if you've got any sort of thermostatic control of the fans, but again, simple calculation) And lets say that switching to those electric fans gets you an extra .5 mpg. (Because lets be honest here, nobody is pickup up multiple miles per gallon with this swap, and I've not seen good data, but I think I'm probably being generous by granting that 1/2 mile improvement, I don't care what you try to claim. I *might* be ok with granting you 1mpg, but I find it very hard to believe, on something the size and weight of an OBS F150)

So now the calulation becomes 17.5 X 19 = 332.5 Miles per tank, still $71.25 to fill the tank. So $71.25 / 332.5 = $0.21 per Mile. So you've saved yourself a grand total of 1 Penny per mile to drive the truck. Now, assuming that $75 in parts (no labour calculation, because two guys might take different times to do the swap.) for you to break even on that swap, you're going to need to drive 7500 miles before your break even point.

And if/when you have to replace those electric fans at some point in the future, it's going to be more expensive than replacing a fan clutch (most aftermarket fan clutches are running about $25-40, for standard duty ones, in my experience).

So in summary, yeah you can save a very small amount of money, by swapping to an electric fan setup on an OBS pickup, I just don't think the return on investment is great enough to make it worth my time.

You may well believe that minor efficiency improvement to be worth it, that's a judgement call that every Man has to make for himself.

 

Hey, AB, long time.
I have been using an electric fan for more than 10 years. I experimented with several different types, such as the Volvo fan, the Taurus fan, the contour fan, and for a while I even ran half of the dual fan and shroud from a Ford Windstar. Because the Windstar is set up to use only one fan on low speed, and then kick in the other fan when the high-speed is activated, and because of that the fan manufacturer installed a divider on the backside of the shroud which meets the radiator and isolates one fan from the other, so when one fan is running without the other, the running fan is not simply reusing warm air from the engine bay which is pulled in from the side of the shroud with the non working fan. That half system was a one speed fan, and it was also a small section of the shroud that covered my radiator. Surprisingly enough, that small fan/ shroud Worked quite well. I only changed to the dual contour set up because it made me feel better that the shroud was covering A larger percentage of the radiator. I have always wanted to have a two speed fan, because having the high-speed in reserve is something I find reassuring. But because I have an in-line six, space is very limited, so I stick with the contour system. As I mentioned in my previous post, I recently discovered that the fan motor, the two speed motor found on certain Windstar models, has the exact same shaft that the contour fans have. That is the funny thing about these electric fans. Each fan has a different shaft and uses a different locking system that keeps the fan blades on the shaft, and that prevents inventive people like me from swapping motors into different shrouds. But that is not the case with the Windstar in the contour motor shafts.

The one drawback I find with the contour fan is that I get quite a spike at startup. That made it necessary to install the delay relay which allows one fan to start spending independently of the second fan. And then 10 seconds later the second fan activates. That way there is not such an initial rush of electricity into the fans. I found over the years that I have to sometimes stop myself from doing modifications that are you have read about. I've learned that I want to do them simply out of curiosity, instead of need. And of course installing the Windstar to speed fans into the contour roof dual fan shroud is something I would be doing out of curiosity, just to get a laugh. But the system is working quite well now and fulfills my needs, so for now I have to tell myself to leave well enough alone, darn it.
A couple things that I wanted to mention that others might find very useful are these: I wired each fan through its own relay event one fan or one relay should fail I can still get home, maybe a little warm, but I'll be fine. I also found that using the BMW Thermo switch, if the switch goes out I simply disconnect the ground and the low-speed lead and then connect them together and the fan stays on. Again, I'm not stuck stranded on the side of the road. And I would say to anyone who is pulling a fan of a junkyard, while you're there find an extra fan and take it apart and take the motor. You never know when this model car or fan is going to go obsolete and out of production making it unable to find. Oh, and if you perhaps find a metal clip on one of your fan blades, don't pull it off. That is a balance weight.

 

Various people have dyno'd fans over the years. The TL;DR is that no electric fan comes close to a clutch fan that covers the same sized radiator. If you want something specific to google I think four wheeler magazine did a write up in the early 00s where they compared a bunch of different setups on a SBC swapped Jeep.

OEMs use electric fans for packaging, NVH and fuel economy. There's a reason they still use clutch fans on trucks and vans.

Whoever says that electric fans perform better at low vehicle speeds needs to think before they type. If the engine is being worked hard the fan will be moving plenty of air to go with it. Stationary equipment would overheat if this wasn't the case.

 

You can believe what you want to believe. Don't let facts get in your way.

 

My father and brothers 3yr old f150s have electric fans only. Maybe try watching the test engine masters did on all the different fan setups and see how much power you lose.

 

I've seen them. Of course it takes more power to move more air.

 

I wanted to post a link to what seems a good quality controller. I have not tried these, but wanted to post this product as an alternative to the big name controllers—many of which have quite a bit of negative press about premature failures. These controllers are handmade in the guys garage and look pretty cool and are beefy. They come with PWM (slow start Pulse Width Modulation). https://www.autocoolguy.com/