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Which is Better – an Electric or Belt-driven Fan?

2010 February 27
by admin

This debate is as old as the electric fan itself. We manufacture both, so we’re pretty unbiased on this topic. In fact, we created the first high-performance belt-driven fan in 1962, and we were the first to introduce an aftermarket electric fan to the U.S. in 1978.

We’ll jump right into the heart of the matter: An electric fan is the better performance solution, freeing up maximum horsepower and mpg. But it’s not always the better cooling solution. The full answer to this question is that both electric and belt-driven fans have their place. Which one is better depends largely on the specific application.

All fans consume energy to spin. Belt-driven fans use mechanical energy directly from the engine. Electric fans rely on electric energy from the battery and charging system. But in cooling, what makes a good fan is optimum airflow for cooling with minimum energy consumption (for maximum engine power and fuel economy).

Electric Fans

An electric fan completely removes the mechanical load of spinning the fan from the engine. It places an additional draw on the electrical system, but this is a more efficient means of spinning a fan, and it has a smaller impact on engine drag. Between the two types of fans, an electric fan offers an improvement in power delivered to the wheels.

Removing a belt-driven fan that mounts on the water pump reduces the load on the pump. This can lengthen the life of the bearings in the water pump.

One huge advantage that electric fans offer is flexibility in when they are turned on. An affect that most people don’t consider is that your engine can come up to operating temperature more quickly with an electric fan because the fan doesn’t turn on until a specific temperature. This is nice in the winter time to warm up your car more quickly, and it’s critical in drag racing where you want just the right amount of engine temperature of optimum performance. An electric fan can cycle on and off, reducing the electric load. You can wire them to come on when the air conditioning is turned on to maximize the efficiency of the air conditioning system. For a 4×4, you can also add a manual kill switch to turn the fan off during a mud run or water crossing to minimize pulling more than just air through your radiator.

Another advantage for electric fans is packaging. We don’t mean putting it in a box, but rather how it fits underhood. If you’re making engine or cooling system changes, the original belt-driven fan might not line up any longer, or the factory fan shroud might not fit. Electric fans are designed to mount directly on the radiator, usually providing for the most compact and easy installation possible. They can also fit in very tight spaces. A belt-driven fan will typically require at least 3 ½ inches between the water pump and the radiator, while our Low Pro electric fan requires only 1.09 inches at the center where your pulley is. For vehicles where the engine and radiator/fan shroud move a lot – like in off-roading – an electric fan eliminates the possibility of the fan hitting the radiator or shroud.

Finally, if you’re installing a custom radiator, adding an electric fan is easy and will clean up your underhood considerably. In fact, we offer a line of aluminum radiators that are available with an electric fan that is optimized for the radiator.

Belt-driven Fans

If your vehicle has a belt-driven cooling fan and you’re not making major changes to the engine or cooling system, the simplest thing to do is to keep a belt-driven setup. You can, however, increase your car’s horsepower and fuel economy without giving up cooling capability by using one of our high-performance flex fans.

Since a belt-driven fan increases speed (and airflow) with engine speed, it can move more air at higher engine rpm – usually above 2,400 rpm – than an electric fan. Conversely, electric fans move more air than belt-driven fans at engine speeds below 2,400 rpm in typical applications.

One major downside of belt-driven fans is parasitic loss. It simply takes more energy to spin a belt-driven fan than it does to produce the electricity needed for a comparable electric fan.

Here are some of the applications where we would recommend a belt-driven fan. They are better able to pull air through a restrictive cooling unit. If you have a four-core radiator with an inner cooler, air conditioning condenser and transmission cooler stacked in front, a 7-blade flex fan along with a proper-fitting fan shroud will be a great choice for cooling. A belt-driven fan is also a good choice if you are having a cooling problem at higher engine rpm. A lot of off-road vehicles drive at slow speeds with high engine rpm. This can build a lot of heat without any natural airflow through the engine compartment. A thermal clutch fan will make use of the high engine speed to move maximum air.

Which is Right for You?

That’s the key question, right? Here’s our advice: If you are looking for a performance upgrade then the electric fan is for you. Make sure the electric fan covers 70 percent of the radiator core and moves enough airflow for the engine size (a rule of thumb is at least 2,800 cfm for a 5.0L engine). The electric fan would be a cooling solution for vehicles that typically drive at low vehicle speeds with low engine rpm, such as cruising. If you have a 4-core radiator or towing heavy loads then we recommend you stick with a belt driven fan. Finally, if you have a cooling problem, watch this blog for future articles that will help.

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