Which Kind of Engine Fan Eats the Most HP?

We've published a few other videos in this series which have all been about INCREASES in horsepower. In this segment, you'll find out which engine fan DECREASES power the most. The irony is what is taken away may also be what is most needed. Read more below.

Logic tells us, the older the cooling system, the greater the corrosion and the greater the corrosion, the less effective the cooling system. We've also been informed about another type of corrosion...electrolysis; which can eat your Classic's engine from the inside out. Especially any and all aluminum components. There are no cooling fans which can offset either type of corrosion, so it remains critical to assess how much and how bad any existing corrosion has decreased the cooling capacity of your Classic. If corrosion has overrun the entire system, changing the water pump, the fan or the thermostat will be ineffective at best.

This is truly about how you use your Classic. If you've turned it into a race car, you want all the power possible and at high engine RPM's. But if you simply enjoy a powerful engine that spends most of the time in the 1,000 RPM to 4,000 RPM range, those past articles prove a giant exhaust system, headers and similar additions are not really needed. Yes, there will be a power loss at 6,500 RPM at wide open throttle, but truthfully speaking, does it make much difference if you have 600 HP or 620 HP? Probably not.

As noted in the above video, certain fans require significantly more power to operate at higher engine speeds, but what is the "fitness of purpose" you desire for your personal use? From a practical point of view, we believe most people would rather prevent a condition of overheating while Summer cruising than worrying about the car next to you having 22 more horsepower at 7,000 RPM. Besides, even if your car is more powerful, do you really want to be the center of attention as your car overheats, puking gallons of rusty green water onto the street while steaming like an old locomotive?
Taking in all of the above, the cooling fan that is best at absorbing the most power is also the cooling fan that increases the airflow through the radiator best...to a degree. Yes, Virginia, there are always compromises. The clutch-less steel blade fan does eat the most power/provide the greatest airflow, but the plastic-bladed fan does nearly as well without the weight or fear it will self destruct the next time you plant the loud pedal to the floor, just because.

Conversely, use of a clutch fan, which ate the least power, does not necessary mean it will provide the greatest air flow when it is needed the most. They were designed for "stock" applications where the engineers weighed the pros and cons when it comes to "normal" passenger car use. It's common knowledge clutch fans HATE high RPM and there are two different types of clutch devices-one works off temperature, the other engine speed. This set up may very well be the best choice for some applications, but not necessarily all.
It's important to have a well tuned cooling system appropriate to your preferences and needs, but how you get there should be given a fair amount of due diligence. What about electric fans? Well, that topic will require a completely separate article. Until next time...