I am a big fan of electric fans. In my opinion there is no reason not to run an electric fan. They free up horsepower, do a better job of cooling, and perhaps the most overlooked benefit is that they are safer than belt driven fans. If you have ever seen an aftermarket flex fan, you know that the steel blades are sharper than a set of ginsu knives. Getting your finger nicked while checking timing is a painful and bloody experience, trust me. I've also seen a couple cars with gapping wounds in the hood from where a blade cut through when the rivets broke loose.

In terms of power, the benefits are clear -anytime you free up the load on the crank, you free up horsepower. Upgrading from a fixed blade or flex fan to an electric fan can free up as much as 25 horsepower at high rpms. The problem with fixed bladed and flex fans is that they develop enormous drag at high engine speeds. However it is at high engine speeds when the fan is least needed, because the velocity of the car moves more than enough air through the radiator to cool the engine. While today's clutch style fans are admittedly more efficient than the earlier fixed blade or flex fans, a clutch fan is still belt driven and that takes some power to turn. Swapping out a clutch fan will still net 10 -15 horsepower as the rpms increase.

Perhaps the greatest level of apprehension regarding electric fans, is the fear of their ability to sufficiently cool the engine. While it is true that selecting the wrong electric fan can cause the engine to run hotter, selecting the correct fan for your application will actually cool the engine just as well as a stock fan, and in many cases will alleviate problems with a engine that runs too hot. Most engines get hot while idling in traffic, or while moving at low speeds. This is simply because stock style fans spin at a rate directly proportional to engine speed. At idle the fan is turning at under 1000 rpms, not nearly enough to dissipate coolant temperatures of 200+ degrees. However an electric fan, such as the Black Magic fans, spin at 2200 rpm as long as it is getting 13+ volts from the charging system. This moves significantly more air through the radiator core.

Anybody that races, be it drag racing, autocross, or open track, knows of an additional benefit of an electric fan; the ability to rapidly cool or warm-up the engine is a must. Between rounds of a bracket race you need the ability to quickly get the coolant temperature down, and an electric fan with a manual switch lets you run the fan while in the staging lanes. Conversely if you've been staged for a while and the engine is dead cold, you have the option of running the engine without the fan to get it up to operating temperature quickly. A stock fan works against you in this instance, cooling when you don't want it too.

So when the clutch fan in the '88 project car gave out, we figured it was good time to go electric. Since the car sees over eighty miles of stop and go freeway commuting, it was critical to get a fan designed specifically for the 5.0 engine. This meant that it must be thermostatically controlled, as well as having a manual switch option. The fan also needed to have an AC activated switch (air conditioning places additional cooling demands, thus you want a fan that switches on automatically when then the AC is turned on.) Finally the fan had to be a direct, no-hassle, bolt in. Many "generic" electric fans only come with the ability to run a manual switch. This is fine for a strip car where you are constantly monitoring the temperature. However on a daily driver, you definitely do not want the responsibility of watching the temp gauge every few minutes. Let a thermostatic switch control the fan when the temperature reaches a preset level.

After doing some research, the Black Magic 5.0 fan from Flex-a-lite was by far the most complete assembly available. For approx. $180 the fan is not the cheapest out there, but for all the features and ease of installation, it is easily worth the price.

It is designed to fit the stock 5.0 radiator, and comes prewired with a built-in relay box for the thermostatic switch, AC switch, and manual override. You can always tell when something is engineered well when it requires no hacking or drilling, and allows you to reuse stock components. With this fan you reuse the stock over flow bottle, and also the the little nut clips from the stock shroud (refer to picture captions below.) The fan comes complete with everything you need to do the swap, including wires and crimp terminals. The only item you need to make a trip the parts store for is a toggle switch, if you desire the manual switch feature.

The install took less than two hours, with most of that time spent on figuring out how to route the wires cleanly. The results are better than expected. We weren't expect to feel a power difference over the clutch fan, however it is definitely noticeable over 3000 rpms. The engine pulls faster and smoother from 3000 to 5500. As an added benefit the engine noise is substantially less while cruising on the freeway, since the fan is usually in the off mode.

As far as cooling goes, we tested the car out on a 100 mile drive into central California. Air temps were in the 90's. There was no difference in coolant temperature at freeway speeds with the AC off. However since it was a hot day, we had the AC on most of the drive. It seemed to run about 10 degrees warmer than with the stock clutch fan, but this is probably due to not having the thermostatic switch set low enough. The engine has a 180 degree thermostat and we set the thermostatic switch to come on somewhere around 190. While 190 doesn't concern us at all, If you plan to run the AC quite a bit you could back this down to 180 and run a little cooler. F/M

Installation is clean and simple. The engine runs just as cool, but with slightly more horsepower and the benefits of cooling on demand.
Flex-a-lite Consolidated
P.O. Box 580
Milton, WA 98354
(253) 922-2700
FAX: (253) 922-0226

Flex-A-Lite Black Magic 175
Flex-a-lite Black Magic Fan
for 5.0 Mustangs (Part# 175


Mounting Surface 18" x 16" x 4 1/4"
Fan Diameter 15"
Fan RPM@13.5V 2200
Blades/Angles 8/26 deg.
Air Flow (cu.ft/minute) 2800
Amp Draw 13.9
Thermostat 180-240 deg.

1. The microcircuitry for the thermostatic switch, AC, and manual switches are all built into the top of the fan. The thermostatic bulb is on the other side and contacts the radiator when the fan is mounted.
2. The stock clutch fan and shroud. Our fan had developed some cracks at the hub and was on the brink of coming apart.
3. Installation begins with removing the stock fan and shroud. Unbolt the fan from the waterpump pulley and then remove the two shroud retaining screws.
4. The stock fan can be removed from the engine compartment.
5. Before removing the shroud, unbolt the overflow bottle. Try to keep it upright to keep any coolant from spilling out. Then remove the shroud completely.
6. Replace the waterpump pulley bolts.
7. Remove the two nut clips from the side of the shroud. These will be used to attach the overflow bottle to the supplied bracket.
8. The nut clips at the top of the radiator will be removed and used for mounting the overflow bottle bracket to the radiator.
9. Shown here is the overflow bottle bracket and reused clips. Attach the bracket as instructed towards the end of the radiator. Then attach the bottle.
10. Many electric fans use cheesy zip ties to attach the fan to the radiator. The Black Magic kit comes with brackets to solidly attach the fan to the radiator frame.
11. Mount the fan and secure the brackets.
12. The final step is to deal with the wiring. You need a 12V source to the battery (red shown here), as well as a 12V ignition source (blue). The Green wire in this photo is connected to the AC power source. The black is ground. The empty terminal is for the optional manual switch -wire it to a toggle switch under the dash somewhere.
The little knob at the top of the box is the control to set the temperature at which the fan comes on. There are no temperature gradations on the box, but the range is between 180 - 240 degrees. With the engine at operating temp, rotate the knob until the fan turns on. A eigth turn higher and you're set.
13. If you run AC, be sure to splice into the power lead for the compressor. This will ensure that the fan kicks with the AC to provide added cooling.
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