Davies Craig EWP® Pt. 5 - How To Install The EWP® As An Auxiliary To The Stock Mechanical Water Pump

26/09/2019 12:00AM

Davies Craig EWP® Part 5 - How To Install The EWP® As An Auxiliary To The Stock Mechanical Water Pump

When used as an auxiliary to your engine’s standard issue mechanical water pump, a Davies Craig Electric Water Pump will increase the flow of coolant through your engine, particularly when operating under high stress conditions or elevated temperatures. In fact, both the existing belt driven mechanical pump and the Davies Craig EWP® will pump through each other when running alone and they will boost each other when ruining at the same time.

Beneficially, when running together they will actually pump more than the sum of each pumping alone.  

To cater for the variety of engine capacities and the varying demands different engines must withstand, Davies Craig HAS developed 4 sizes within ITS EWP® range; the EWP80, EWP115, EW130 and EWP150. Refer to the table below for sizing and suitability information.



Engines up to 2.0L (Standard)


Engines up to 2.0L - 3.5L (Standard)


Engines up to 3.5L - 5.0L (Standard)


Off Road / 4WDs

EWP®130 or EWP®150

Engines 5.0L or greater (Standard)


Modified Engines, Supercharged, Turbo

Drag Racing, Drifting & Speedway


Installation consists of placing the EWP® in the preferred operating position where it cut into the lower radiator hose AND is wired directly to the battery. A section of approximately three to four inches, depending on your setup, can be cut from the hose and the EWP inserted into the gap. Securely clamp the EWP®’s inlet to one of the remaining sections or hose, and the outlet to the other.

From here, a temperature sensor or thermal switch can be inserted into the upper hose connection at the radiator. This allows the EWP TO OPERATE WHEN TH EENGINE TEMP REACHES YOUR CHOSEN CUT IN POINT WHILE THE mechanical pump continues TO OPERATE NORMALLY..

This adds increased capacity and effectiveness to your engine’s cooling system. While driving at speed, the mechanical pump will be the primary fluid mover using energy from the engine belt, but at idle the engine’s speed drops dramatically SO THAT mechanical pump  flow  IS just  15 to 20 litres per minute.

With the Davies Craig EWP® fitted and operating, when the coolant temperature reaches a pre-set limit, the EWP® is engaged and supplements the mechanical pump with an additional flow of 80 to 150 litres per minute .

Furthermore, if the EWP® is wired directly to the battery, when you turn off a hot engine, the EWP®  will continue to run and wash out heat soak, cooling down the engine evenly until the engine temperature reaches the pre-set temperature less 4c.  After the EWP® turns off, the heat may still transfer and the EWP® will turn on for another shorter period and run for about 30 SECONDS at a rate of 6/9 amps, which draws very little from on the battery.

Our next instalment will be: How to install the EWP® whilst keeping the disengaged mechanical pump in place.