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
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
is clean and simple. The engine runs just as cool, but with slightly
more horsepower and the benefits of cooling on demand.
P.O. Box 580
Milton, WA 98354
FAX: (253) 922-0226
Black Magic Fan
for 5.0 Mustangs (Part# 175)
x 16" x 4 1/4"
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
The stock clutch fan and shroud. Our fan had developed some cracks
at the hub and was on the brink of coming apart.
Installation begins with removing the stock fan and shroud. Unbolt
the fan from the waterpump pulley and then remove the two shroud
The stock fan can be removed from the engine compartment.
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.
Replace the waterpump pulley bolts.
Remove the two nut clips from the side of the shroud. These will
be used to attach the overflow bottle to the supplied bracket.
The nut clips at the top of the radiator will be removed and used
for mounting the overflow bottle bracket to the radiator.
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.
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.
Mount the fan and secure the brackets.
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.
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