ConclusionAfter testing-of both the OEM-style water pump and fan on the dyno versus the Meziere electric water pump and SPAL 16-inch puller fan-the results were in a word, shocking. While expectations prior to testing were to gain 5-10 hp, a gain of 19 hp at the peak was phenomenal, especially when torque followed right along.
Keith Lohse of RPM states, "Dynos are simply tuning aids that provide relative power and torque gains, and with that in mind, we like to focus on the area under the curve and the averages rather than the absolute peak numbers. Average horsepower and torque are better indicators of real-world gains, and in this case almost 15 hp and 16 lb-ft of torque are impressive. Those types of gains will definitely be felt on the street and should be recordable at the dragstrip."
After sharing the results with David Butler of Butler Performance, he commented, "Our testing on engine dynos consistently shows gains in the 10-15 crankshaft horsepower range. Although the HPP tests showed higher gains, factors such as the brand and relative condition of the water pump and hydraulic clutch fan can definitely make a difference. There is no doubt that the reduction in parasitic drag allows gains. Our customers attest to that on a regular basis."
As time marches on, the OEMs have slowly but surely replaced belt-driven fans with electric fans in order to have less parasitic drag and improve upon their corporate fuel economy standards. Although electric water pumps have not been widely used by the OEMs, it's a pretty safe bet that the decision has more to do with the economics of the parts rather than the efficiency. Let's face it, a cast water pump most likely costs less than an advanced design electric motor such as those found on the Meziere pump. Although costs and fuel economy weigh into the decision-making process of the enthusiast so, too, does the allure of increased power.
If your ride is in need of a cooling system upgrade, there are many avenues to explore. For those enthusiasts who aren't concerned with keeping a "stock-appearing" system, consider checking in with the vendors outlined in "Cool Winds." In addition to significant cooling system performance gains, it's nice to know that you can have your cake and eat at the horsepower trough at the same time.