Electric Water Pumps

From Holdenpaedia
Revision as of 11:08, 4 October 2007 by ReaperHR (talk | contribs)

Jump to: navigation, search

Back to Cooling

This page is created and researched by third parties completely unrelated to the company Davies, Craig. Davies, Craig at no time has had any input into this or related pages in the Holdenpaedia or Work Guides other than to lend assistance when required and supply the products. Davies, Craig is not currently and never previously been a sponsor of oldholden.com, nor asked for the guides/pages to be done. These pages and guides were all done by myself for my own interest and to try and curb some of the lies and BS that is on the net by parties with little to no current understanding or experience with these products. They were done to help interested members of the community see what is involved in installing these products and what they are capable of doing. At no time did Davies, Craig approach me and ask or pay for these pages to be done and at no time did they influence any of the results or comments. ReaperHR (Greg)

By ReaperHR

A Davies, Craig Electric Water Pump and Controller

A standard belt driven water pump is inefficient and in effect is technology that is over 50 years old. By adding a taste of the 21st century you can regain horsepower, give more care to the engine and make it more efficient in trying conditions. For the sake of this page the Electric Water Pump being referred to is one that is produced by an Australian company called Davies, Craig Pty Ltd.

As a possible modification to your Holden the Davies Craig Electric Water Pump is an interesting and efficient item that is designed to keep your motor running well under any circumstances from hot days in traffic to very cold conditions. The *EWP from *DC is designed to be able to suit many different makes and models of vehicle and have infact been used on a Ferrari during a Le Mans 24 hour race where the Ferrari won, the Ferrari was a V12 6L 550 Maranello and used two EWPs and it also later won again in the American Le Mans series event in Miami of October that year. This shows how robust an EWP is, to survive not only intense action on the race track but for the full 24 hour event is an excellent indicator. They are infact rated to last for 2000 hours of continuous usage at 180F (80C).

The EWP is designed to assist or replace the standard belt driven pump by being installed in the lower radiator hose. If the EWP is used to replace the standard water pump it can remove some of the drag from the crankshaft (that is normally created by the standard pump) by using a shorter fan belt to skip the standard pump or by removing or otherwise disabling its impellor. With the standard water pump disabled the motor will rev easier and will also reportedly regain around 15% to 20% of horsepower at high engine revs.

A Davies, Craig Electric Water Pump Kit

Electric Water Pumps work by accepting an adjustable input voltage that adjusts the flow of the pump, if used in conjunction with the Davies Craig Electric Water Pump Controller the EWP will be supplied with the voltage it needs to adjust its speed and therefore the flow of the coolant into the motor to suit the conditions it is in. What this equates to is a pump that knows what your motor needs and supplies it, compared to any standard water pump the EWP is by far superior. The series 2 EWPs from DC (currently manufacturing series 3) supply a constantly moving stream of water even when the motor is cool, meaning that it doesn't just suddenly "switch on" and push cold water from the radiator into the motor, rather it adjusts the speed of flow to suit the temperature.

Another benefit of the EWP is that with a controller you can adjust its temperature range so that it will attempt to either keep the car a little cooler than standard or a little warmer or anywhere in between. A higher operating temperature gives better fuel economy while a lower operating temperature gives more power, what other engine mods are so easily adjustable for your needs?

As an example of a standard day without an EWP and with an EWP:
Without EWP With EWP
In the morning you start your car, the water pump supplies a flow of water through the motor, being slowed solely by the thermostat. In the morning you start your car, the thermostat has been removed as per recommendations with fitting an EWP and not having a standard water pump, therefore there is nothing to stop the flow of coolant through the motor. Instead of the water flowing at a speed related to the engine revs though the EWP is allowing only a small flow of coolant through.
Your car is now up to operating temperature, the thermostat slowly opens and coolant begins to flow. Your car gets up to operating temperature and the EWP continues to monitor what flow of coolant is required to keep the engine at that temperature.
You hit a traffic jam, or a heap of traffic lights, your car continues to idle but there is little air flowing through the radiator to cool the coolant, your temperature starts to rise. The coolant is flowing as slow as possible also due to the lower engine revs. You hit a traffic jam, or a heap of traffic lights, your car continues to idle but there is little air flowing through the radiator to cool the coolant, but the EWP continues to monitor the engines temperature and adjusts the flow of the coolant to suit. The EWP is adjusting the flow so that it is going slower than the standard water pump could flow or higher than it could flow at extreme revs or anywhere in between as is needed. At this stage if you also used DC Thermatic Fans you would also have a flow of air through the radiator equivalent or better than driving on a highway at speed, even though you are stopped
You finally get home with your overheated motor and shut it off, there is now no flow and the coolant rapidly fails to do anything as it sits still in the motor and begins to heat up, now rather than cooling your motor it is maintaining the heat that is in it. You get home with your motor that is still sitting at ideal operating temperature and switch it off. Now if you use an item like a turbo timer you can have the EWP to continue to operate and cool the motor, avoiding any heat soak, after a few minutes (however many you have it set to) the EWP shuts off and your motor is left in a much better condition, not only did it not overheat, it was also allowed to cool past the point where the other motor could have.
You go for a long drive and notice the car overheats easily even at speed on the highway, most likely your thermostat has failed and no coolant is flowing, time to pull over and pull it out and replace it (if you have a spare in the car and a gasket) or go into a mechanics and hope they can fix it without bankrupting you. Your thermostat has failed, luckily it's sitting on a shelf at home since you no longer need it, the EWP alters the flow as needed, you no longer have to trust such an unreliable mechanical device as a thermostat to adjust the flow.
You take the thermostat out so that the car stays as cool as possible. The motor now has no restrictions to coolant flow which isn't as good as it sounds. It means slower warming up, and a coolant flow that is solely based on engine revs, even when cold. A cold motor is also less fuel efficient. You take the thermostat out (as required when using the EWP alone). The coolant flows very slowly when warming up, much like if the thermostat was still there, but is not dependant upon engine revs but rather the conditions the engine is going through.  


  • DC - Davies, Craig Pty Ltd
  • EWP - Electric Water Pump

For information on installing an EWP:

Contact Davies, Craig

An installation work guide done on a HR Holden

Information for this page was gathered from the following sites:

Davies, Craig Electric Water Pump Page

An early introduction to Davies, Craig EWPs

A review of the EWP

and from the following members personal experiences:


Back to Cooling