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Fan Upgrade
By Mike Bumbeck/
Printable version
Degree of DifficultyDifficult
Estimated Time240 minutes
240 minutes
How to Keep Your Fans Happy -
An internal combustion engine needs three precious ingredients to create power: air, fuel and spark. On the path to more power, the automotive performance enthusiast will endeavor to squeeze more air, fuel and spark into the engine in order to get more power back out of it. More power is always welcome, but as with any performance modification there is always a tradeoff. As anyone who has thrown a few more logs on a fire knows, the more fuel, air and spark added to any combustion situation, the more heat produced.
Before and After Radiator Fan Replacements
The same thing happens inside an engine when you add more fuel and air and light it on fire by turning the key. More fuel, air and spark can indeed create more power, but more power can bring a corresponding rise in operating temperature. The additional heat can overcome the vehicle's stock cooling system and the engine can run hot. This is especially true when a water-cooled turbo is thrown into the performance mix, or a bigger engine is crammed into a tiny engine compartment. Excess engine heat can cause a myriad of problems, from premature engine wear to peeling and blistered hood paint. The solution is to upgrade the cooling system of the vehicle to get rid of the heat produced by the engine performance upgrades. One of the best ways to do this is to get more air flowing through the radiator in order to remove the additional heat.
Your Biggest Fan
Back in the day, most automobile engines used a fan that was connected directly to the water pump and spun by way of a belt connected to the crankshaft. This fan either spun, as did the engine, or had a viscous clutch assembly sensitive to changes in heat, and turned on and off accordingly. While this setup works fine for cooling, the problem with this equation is that any accessory driven by the engine takes horsepower away from the place where it should really go—to the wheels. To the performance nut, squeezing every bit of available horsepower out of the engine is the answer, so engine-driven fans are not.
Many modern vehicles use a system of switches, relays, and electric fans to force air through the radiator and vent away heat. The fans turn on and off as needed by way of heat-sensitive switches. The switches complete the fan circuit when the coolant reaches a certain temperature, say 180°. When the coolant reaches the designated temperature, the fan goes on and blows heat out of the engine compartment. All this without using any horsepower is better employed for climbing hills, towing a boat, or motoring down the drag strip.
Another problem with an engine-driven fan is space. Low profile electric fans with thin yet powerful pancake-style electric motors take up little space in the engine compartment compared to an engine-driven fan. An upgrade to electric fans is the answer for a few more ponies over an engine-driven fan, or if fit becomes a problem with the addition of a bigger than stock engine, or a turbocharger or supercharger and associated plumbing.
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