Vintage Pontiac Cooling System Upgrade

If your Poncho suffered from any cooling system problems before storing it for the season, you still have time to address the issues and ensure that overheating becomes a distant memory. For those of you lucky enough to have a top-notch cooling system, maybe it's time to shift your focus to how much additional horsepower can be gained by reducing the parasitic drag of the factory water pump and engine cooling fan.

In Part I of this story, we introduced you to Floyd Hand's '66 Tempest. This 0.030-over 455-equipped car is used for both cruises and heading out to the track to knock down mid-11 second quarter-mile times. After determining that the stock-type cooling system was in need of an upgrade, we took you through the installation of a custom aluminum radiator from Performance Rod and Custom (PRC), a SPAL 16-inch electric fan, Meziere electric water pump and Butler Performance Alternator Relocation kit.

Then in Part II, we tested the effectiveness of the cooling system upgrade and finished up by providing temperature test results that detailed improving cooling system performance for drag racing, around-town driving, and extended highway use. When you are able to drive for 50 highway miles at the posted speeds and maintain 190-degree coolant temps in the Texas heat, you know you have an efficient system. Though a Meziere electric water pump is primarily used by bracket racers, we proved that it was very capable for street and highway driving.

Now that the system has been installed and the basic temperature tests are complete, it's time to find out if there is a horsepower advantage to employing an electric water pump and fan over the factory-based components.

The '66 utilized an OEM-style four-core brass-and-copper radiator with a shroud from a GTO. Equipped with a stock-type iron water pump and 7-blade factory clutch fan, the cooling system was in good working order, but was due for an upgrade.

Tag along with us to Real Performance Motorsports (RPM) in Lewisville, Texas, as we hunker the Tempest down onto a DynoJet 248 chassis dyno. So confident were we that the installation would be a breeze that our mechanics Floyd Hand and Marty Parker never bothered to ask that the Tempest be unshackled from the dyno to swap components.

The Parts
The baseline setup consists of a stock-style belt-driven iron water pump and a factory 7-blade clutch fan. The hydraulic clutch allows the fan to freewheel and save some horsepower until the fluid heats up to a predetermined temperature. The fan then engages and spins at the same speed as the water pump pulley, via the fan belt. When the temperature drops, the fan once again freewheels. By having to rotate the water pump and fan via the crank pulley and a belt, the engine will be using power to spin the components, thereby reducing the available amount of power that can be transmitted through the driveline and, ultimately, to the rear wheels.

In contrast to the factory parts, the Meziere heavy-duty water pump is electric-powered so the belt that drives a stock-type water pump is completely eliminated. Since the pump is powered by a self-contained electric motor, there's no mechanical power required by the engine to turn it. The same set of factors applies to the SPAL16-inch electric puller fan and the electrical accessories that regulate its operation. By eliminating the engine fan belt and the mass (fan and hydraulic clutch) that the engine must turn to produce enough air for low- and high-speed cooling, there is less parasitic drag.