A cool new concept

Electric water pumps for automotive use have been available for some years, but for mainly they’ve been used for racing applications. Self-contained electric water pumps are often used in drag racing between runs. The aim is to reduce the engine’s temperature and the parasitic power loss of a mechanical water pump.

Early attempts to use race-style electric water pumps on the street weren’t very satisfactory, but all that has changed, and in fact one European manufacturer began using electric water pumps around 2007, and several others are following suit. Now there are aftermarket versions that are suitable for regular daily drive use.

Over the past 45 years the Davies Craig engine cooling product line has grown, and now includes its revolutionary electric water pump, or EWP, manufactured and sold in Australia, and now exported to NZ, US, Europe, and Japan.

An EWP has many advantages over the engine-driven variety. It will increase power and torque by disabling the mechanical pump, which uses engine power to drive it. Additional benefits are improved cooling capacity and fuel economy, and the elimination of engine heat soak after a hot engine shut down. Engine cooling is improved thanks to a higher flow rate at idle and low engine speeds, when there is little or no ram air, and when the engine is switched off.

Here’s what Davies Craig’s sales and marketing manager, John Benson has to say:

What do you consider normal operating engine operating temperature?

This is dependent on the type, size, capacity, workload and environment, but the best engine temperature is usually between 185 deg.F - 221 deg.F. The manufacturer recommends optimum operating temperature via the mechanical thermostat in the engine, and this is the exact temperature setting recommended when the Davies Craig LCD EWP/fan digital controller is installed.

How does the pump accommodate varying engine speeds?

The EWP operates independently of the engine’s speed, a major benefit over mechanically driven pumps which only circulate coolant while the motor is running. When used with the controller, the pump speed is increased and decreased based on the engine’s operating temperature, instead of rpm. This means the engine’s temperature will determine the pump’s circulation capacity of the engine coolant.

Once the engine temperature begins to climb, the pump’s speed increases accordingly. When the engine’s temperature reaches 5 deg.C below the pre-selected targeted/set operating temperature, the EWP will increase the flow rate, reaching 100 percent. When the engine temperature rises +3 deg.C above the set/targeted