Electric Water Pumps fit most makes and models and is usually mounted into the bottom radiator hose. You just cut out 100mm (4 inches) of hose and let the EWP in. The existing water pump housing is still required as an inlet into the engine block, or a blanking plate can be manufactured to bolt up to the block with an inlet for the radiator house to replace the old pump. It is recommended that you do not ‘hard mount’ your Electric Water pump. When firmly fixed to the chassis or engine, the EWP® may bow which disturbs the shaft seal and may cause a leak and not reseal when the EWP® cools. The EWP® weight around 1kg, therefore the radiator hose is more than capable of holding your lightweight EWP®.

Should it be necessary to mount the pump we recommend using our mounting kits, part numbers #8700 or #8710 or you can use rubber ‘cotton reel’ type mounts to help cushion the pump against vibration and you can use the extra holes around the perimeter of the base of the EWP for this purpose. A supplementary mounting plate can also be used for mounting purposes. Both kits come complete with all the necessary components required for easy installation and a comprehensive DIY instruction booklet.

The main benefit for using an EWP^® is resolving an overheating engine issue & improved engine temperature control. 

Other important improvement for your vehicle comes from the power the mechanical pump takes from the engine can be reclaimed with the use of an EWP^® hence the fuel savings and increased horsepower. By removing the parasitic power losses of belt-driven water pumps, the EWP^® may provide up to 10kw of extra power and additional fuel savings. The engine power used by the mechanical pump increases as the cube of its speed – so when the mechanical pump speed doubles from idle speed say; 600rpm to 1200 rpm, the power it takes increases by eight times. Then another eight times going to 2400 rpm, and so on up to maximum engine speed. It is this extra power and torque that is released by deleting the mechanical pump that provides the fuel savings that is estimated to be 3.5% to 10%.
 
Major European Manufacturers have implemented EWP’s^® as standard issue on a number of their vehicles and our research shows that an EWP^® uses 90% less energy than conventional systems, i.e.: the mechanical water pump. Other advantages will include lower emissions by virtue of faster engine warm up, better engine temperature management, eliminating engine heat soak and improved engine life.
 
Weight reduction is another benefit and key requirement of any automotive manufacturer seeking fuel savings and better performance. Our EWPs^® weight between 900 grams up to 1,151 grams dependent on the EWP^® model whilst a typical mechanical pump is in the range of 3kg up to 5kg. Not only is our EWP^® considerably lighter, the universal flexible mounting around the engine bay provides options when seeking space within a crowded engine bay for other modifications. 

If you choose to use the Davies Craig Digital Controller you should remove the engine’s thermostat – the Controller is the new “thermostat”. The Digital Controller allows you to electronically set the engine target temperature and it adjusts the rate of coolant flow, hunting for, and then locking onto the temperature you set. You can set the target temperature from 40°C (104°F) to 110°C (230°F) for either economy or performance, unlike your thermostat, which is set at one temperature by the engine manufacturer

If you want extra power and fuel savings you will need to remove or disable your existing mechanical belt driven water pump . Alternatively you may wish to keep your existing mechanical pump and use the Electric Water Pump as an auxiliary pump.

All EWP® Electric Water Pumps fit most makes and models and mount into the bottom radiator hose. It is recommended that you do not ‘hard mount’ your Electric Water pump. When the EWP® heats up the body of the pump will expand slightly. If the EWP® is located in the hose only, the expansion is no problem. When firmly fixed to the chassis or engine, the EWP® may bow which disturbs the shaft seal and may cause a leak and not reseal when the EWP® cools. The EWP®'s are lightweight therefore the radiator hose is more than capable of holding your lightweight EWP®. Should it be necessary to mount the pump we recommend you use rubber ‘cotton reel’ type mounts to help cushion the pump against vibration.

Customers with large race engines are having great success with two EWP®s mounted in line. One is controlled by a Davies, Craig Digital Controller (Part no 8002) set to its target temperature and wired to the ignition. The other is run by a standard on/off thermal switch (part no 0401) wired direct to the battery, and set to cut in at a few degrees hotter than the Controller target temp. When the Controller is running the first EWP® at full speed and the engine temp still increases, the Thermal Switch kicks in the second EWP® and runs it until the engine temp drops 4◦C. in the same way an electric fan is controlled. When the engine is shut down hot, the second EWP®, being wired direct to the battery, will run until the engine cools. The same Thermal Switch used to run an electric radiator fan can be used for the second EWP®. In this case, make sure the fan and EWP® are wired directly to the battery. Both the fan and the EWP® will run on hot shut down, typically for as little as 20 seconds, to cool the engine.

Davies Craig recommends you fit an EBP® Electric Booster Pump part no 9050, to engines equipped to run on LPG where a constant flow of coolant is essential to ensure the LPG regulator does not freeze up on a cold start. This very compact unit fits in the engine’s heater hose lines and offers up to 23 litre/min of coolant flow.

The extra current is very little. About 90% of total motoring time the EWP will run at 10% of its maximum speed using about 2 amps. Being in nylon, the impeller can have aerofoil cross section and the tip clearances can be very small. A mechanical pump has to perform at 600 rpm and 6,000 rpm and it cannot be efficient at both these speeds and all speeds in between. Furthermore, as the power the pump requires to operate increases as the cube of the speed - when the mechanical pump is operating at the higher speeds, as it does, as a car passes through its gear range, its ‘robbing’ engine power in the order of 6 to 10kW. The EWP® which uses at maximum speed 9 amps x 13 volts gives 120 watts at say 30% efficiency from the alternator to hydraulic power means about 0.4 kW to drive the EWP®, when it does operate at full speed

Where there is a thermostat bypass in some engines including those produced by BMW & ROVER, there may be a bypass from the thermostat housing back to the water pump chamber so when the thermostat is fully closed, coolant passes directly from the engine block to the thermostat housing and then straight back to the block without passing through the radiator. When fitting your EWP® to an engine which uses a bypass valve style thermostat, after you have removed the thermostat, you will need to block off the bypass passage (with a core plug or similar), to prevent flow from your EWP passing directly back to the radiator without passing through the block.

The EWP® is designed for maximum efficiency at its maximum speed of 2250 rpm. Being in nylon, the impeller can have aerofoil cross section which gives lift and the tip clearances can be very small. The mechanical pump has to run at 600 rpm and 6,000 rpm and it cannot be efficient at both those speeds and all speeds in between. Furthermore, as the power the pump takes increases as the cube of the speed - when the mechanical pump is operating at the higher speeds, as it does as a car passes through its gears; it is taking power of the order of 6 to 10 kW. The EWP® uses at maximum speed, which is usually less than 20% of total motoring time, 9 amps x 13 volts gives 120 watts at say 30% efficiency from the alternator to hydraulic power means about 0.4 kW to drive the EWP®. The EWP® never needs to run at very high speeds where the mechanical pump is consuming high power and torque. In addition, with the old mechanical pump and a thermostat set up, the thermostat is partly closed most of the motoring time and in a cool climate at highway cruising, it is about 90% closed. As a consequence, the flow and pressure being generated by the mechanical belt driven pump and paid for with power and torque, are choked at the thermostat and wasted. This system has worked reasonably well for a long time but it is not smart. With your EWP and digital Controller, power and torque is never wasted as there is no choking (no thermostat) and only as much flow and pressure as is required is produced. We are starting to see the allowance of EWP® s in racing mostly for the extra power but also to prolong the life of engines with the run on after hot shut down to eliminate heat soak. In any case we cannot stop progress, nobody in racing runs drum brakes or cross ply tyres these days!!

With respect to the EWP fitment in the top radiator hose, there is no negative effect, reduced EWP motor life etc. What is critical however, when the EWP is fitted to the top hose the system MUST be FULLY bled and NO AIR is to be left in the system at any time. The EWPs are not self-priming pumps and as such, should the EWP be operated dry, premature failure of the seals may occur. The reason we nominate the bottom radiator hose is this very good reason as listed.

As the EWP is positioned within the bottom radiator hose, the EWP is a universal fitting pump. The EWP kit comes complete with a range of adaptors to fit hose sizes 32mm to 50mm or 1 ¼“ to 2”.

The max current draw to operate the EWP80 is 7.5A and the EWP115 is 10A. However under average operating conditions the current draw is approx. 2A and 3A respectively. Please see the chart here for the full deatils on the entire range

Davies, Craig performed a number of tests which concluded that a normal water pump uses up to 10kW of power to operate at its high speeds, therefore if it is removed this power is saved and sent to the drive wheels. Not all the power gained will be transferred directly to the wheels as a small percentage will be lost through the drive-train. Each engine is different and the size, capacity and performance of the engine will determine how much power will be gained. Generally higher revving engines such as small capacity and rotary engines will have the biggest percentage increase in power and torque. With the extra power, maximum engine speed will increase so you should be careful that other engine components can handle the extra rpm. A Dynamometer test on the 5.0L V8 VT Commodore measured a 10kW improvement at high rpm and overall increase in torque particularly in the lower rev range.

Davies, Craig P/L conducted tests which showed that each capacity engine had different coolant flow rates i.e. V8 was more than a 4-Cyl. One common V8 has a flow of 24 l/min at idle (600 rpm) and so about 240 l/min at 6000 rpm. That is 240 kilograms of coolant being rammed through narrow radiator tubes every minute. It takes a lot of power to do that. However it was shown by the CSIRO that in a standard engine, flow above 80L/min increases heat loss by very little. Once the flow has reached a rate where all of the heat being produced by an engine is being dissipated in the radiator there is no benefit from pumping faster.

An engine requires a certain flow when it is idling and the vehicle is stationary in high ambient temperatures - say 15 L/min. The flow rates at higher engine speeds are a consequence of the idle flow and are roughly proportional to the increase in engine speed above idle. Invariably the flow rates at high engine speeds are much more than is required given that high engine speeds are transient, as the engine passes through gears, or the vehicle has high road speed and so there is high ram airflow through the radiator. Heat loss is a function of coolant flow and air flow and you do not need both to be at their maximum as the system is designed to maintain engine temperature with both at their lowest values. But you have to have those high coolant flow rates because the mechanical pump speed is a slave to engine speed and if you have 15 L/min at 600 rpm, then at 6000 rpm you will have about 150L/min. That is 150 kilograms of coolant being rammed through the radiator tubes every minute – it takes a lot of power to do that.

The cooling is improved with a EWP by having a higher flow at idle and low engine speeds when there is no or little ram air, and also when the engine is off. But the important improvement for a race vehicle comes from the fact that the power the mechanical pump takes from the engine increases as the cube of its speed - so when the pump speed doubles from idle speed say 600 rpm to 1200 rpm the power it takes is 8 times. Then another 8 times going to 2400 rpm and so on up top 10,000 rpm. It is this power and torque you are releasing, by disabling the mechanical pump, to go to the drive wheels.

The Davies Craig Electric Water Pump, material specifications; Standard PA66 GF30. Thermal properties, continuous working temperature = 135°C, Peak Temperature = 160°C.

Yes, the range of Davies, Craig Electric Water Pumps are precision manufactured using Nylon 66, reinforced with 30% fibre glass or aluminium capable of withstanding various types of inhibitors widely available on the automotive market. This same tough material has been tested and approved by many automotive manufacturers and is the same material designed into the manufacture of radiator side and header tanks adopted by a good number reputable automobile manufacturers worldwide.

Our EBP (Part No.9050) will adapt to 1" hose. While the inlet and outlet is only 19mm (3/4") many of our customers have used this very efficient pump on 1" heater hose lines.

If you have access to adaptors you can order Part No.9051 which is our 'short' EBP, supplied with the wiring loom and without the fittings.

You can run the EBP at constant 6V, some early cars had 6V systems. Obviously it will only deliver half the flow. All our EWPs can be operated at any voltage up to 15 volt, although the 15 volt operation is not recommended for long periods.

On the other hand, not so the Digital Controller, it MUST be operated at 12 volt and if an over-voltage situation occurs the unit may malfunction.

This depends on the vehicle and what the vehicle is used for? Generally for short circuit race/drag applications and engines used under extreme conditions we recommend removing the thermostat to provide the greatest cooling capacity. It is always recommended to use the controller for other applications, however if you have decided not to then we recommend to drill a small 5mm hole in the thermostat to allow some flow and release of back pressure when the thermostat is closed. You may find in these circumstances that the engine temperature is not managed effectively and also the pumps life will be reduced if the controller is not used.

Our EBP's and our Digital Controller (Part No. 8002) can not be used for a positive earth vehicle.

However our EWP pumps can be used in positive earth applications / vehicles, you have to simply reverse the polarity of the pump wires.

Example:

• For our 12 volt EWP's the wires are Blue (positive), Black (earth), simple reverse this wiring in your applications thus Blue wire becomes Earth and Black becomes Positive.
• For our 24 volt pumps, the wires are Red (positive), Black (earth), simple reverse this wiring in your applications thus Red wire becomes Earth and Black becomes Positive.

Therefore you can run these pumps constantly on from ignition or you can use them with our Mechanical Thermal Switch (Part Number 0401) which will switch the pumps on and off at the desired temp. You do lose some functionality in not being able to use the Digital controller (Part 8002).

There is no performance difference between our EWP115 Nylon and EWP115 Alloy. Only the outer housing is in different material.

EWP115 Nylon

Pros: - lightweight (980 grams or 2.16 lb.)
Cons: - No thread on the inlet or outlet to fit screw-in style hose or AN fittings.

EWP115 Alloy

Pros: - Cast alloy housing can be polished for a shiny look.
          - Has AN -16 thread on the inlet and outlet to enable the fitment of screw-in style hose fittings.
Cons: - Heavier than nylon version (1151 grams or 2.56 lb.)

Waterless Coolant puts extra strain on the electric motor and can cause it to overheat and reduce its life. The viscosity of that type of the coolant is the issue and is not recommended for EWP’s

"Waterless coolants increase the load on an EWP and may reduce pump life"

The design of a centrifugal pump means that the Max flow through the system is determined.

The best way to visualise how a centrifugal pump works is to think of it like pushing a weighted box across a rough surface.

If you apply a constant force (or voltage) and the resistance (system resistance) of the surface is constant, then once moving, there is a pre-determined maximum speed the box can move.

If you change the force applied, the maximum speed will change the same will happen when the resistance changes. This will also occur when voltage and system resistance changes.

From the below flow chart, you can estimate the flow rate through the system by looking at where on the flow curve and the system resistance intersect.

In situations where high system pressure is an issue, we recommend looking at using two of our electric water pumps in series.

Example:

Q: I require 5 gpm (18.9L/m) @ 15psi

A: We recommend two of our EWP115 pumps in series which will provide 8gpm @ 15psi or 5gpm at 17-18psi 

It is very important that you understand that our 12 Volt pumps are rated to a MAX voltage of 15 Volt. With that said, our EWP’s use a brushed motor and can be used at higher voltages but the life will be affected.

Running a pump off 16 Volt system although not ideal, won’t be to detrimental to the life of the pump, however running at a voltage above this could cause a significant reduction in life.

You could look at installing a voltage regulator to drop the voltage to protect the pump.

If you were to run a 24V pump the Max performance at 16V will be about 33% less 25GMP (100L/min) .

The lower flow for the 24V pump should not make much difference during a run, and the extra voltage when charging won’t be of any concern and the performance will be increased.

Ultimately the choice is up to you, the 12V pump will have a higher flow but the risk of damaging the pump is higher whereas the 24V pump only has a reduction in performance.

Also, there is nothing stopping you from installing multiple pumps, this would be quite beneficial if running 24V pumps.

Yes, you can run 2 pumps in series, however I would look at using a thermal switch to control the flow of the second pump.

The use of a thermal switch will allow you to always have the additional flow needed and can assist is catching any overheating issues.

The EWP is best mounted as low as possible as this assists in the bleeding process as the EWP is not self-priming.

In general, mounting the EWP in a higher position is not an issue provided it is properly bled of all air before it is turned on.

It is also good practice to try mount the EWP as far away from any heat sources (like the exhaust) to help protect the pump from ambient heat exposure.

Heat exchangers and radiators work in the exact same way. Only with a heat exchanger the air is being cooled not the fluid. It  is quite common for these systems to not run a thermostat, the reason for this is that you are not trying to maintain a constant coolant temp unlike a radiator. This means you want the coolant to be as cold as possible meaning you want as much flow as possible.

When selecting you pump there are a few things to consider,

Hose size
Power output
 

For a heat exchanger system that is using ¾” (19mm) hose the best range of pump is the EBPs in particular the EBP25 and the EBP40

For a Stock performance supercharger I would look at the EBP25 or EBP40, for a higher performance system then the EBP40 is going to be better.

If you have larger diameter hoses like AN16 lines then I would recommend on of our EWPS in particular our Alloy EWP115 and EWP150 as these units have built is -16AN ORB fittings in the inlet and outlet to allow easy adaption to AN16 braided lines.

For stock-mid range performance the EWP115 Alloy is a good choice, but the EWP150 is going to perform very well in the power range.  

If you have a rear mounted tank or a high performance blower then the EWP150 is going to be the best choice.

“Water pressure is a measure of the force that pushes water through the mains and into your pipes. It is measured in ‘bars’ – one bar is the force needed to raise water to a height of 10 metres.”

“ System Pressure is the measure of how much the coolant has expanded due to the increase in temperature, this is important because as pressure increases, so does the boiling point of your coolant. it is also very important that the system pressure does not exceed the max pressure rating of components to prevent damage. in a typical automotive cooling system this is done by the radiator pressure cap.”

The Max pressure rating that we quote is related to system pressure, this is the maximum amount of force that can be exerted on the housing before the pump bursts or begins leaking. The mains pressure should have little to no effect on this because it is essentially the head pressure of the mains supply pump.

If the mains pressure is above the Max pressure this should not be an issue as far as I am aware, because the mains pressure is the force applied to the water and not the force exerted by the water due to expansion.

Davies Craig EWP's have been used in boating applications for many years.
Historically our Electric Fans and EWP's have been used to help cools diesel engines but more recently, they are now used in Hybrid Yacht Propulsion.
They are used to help cool the battery cells.

Davies Craig EWP’s are used as high flow circulation pumps for a closed loop cooling system around a Lithium battery bank in a Hybrid propulsion arrangement.

No, the pumps should not be used with Pure Glycol.

Using pure Glycol will reduce the cooling system capacity as it has a lower thermal conductivity then water. Too much glycol or too high a % will cause system inefficiencies through reduced heat transfer ability and pumping capacity.

There are 2 types of pressure within the cooling system.

System pressure, this is due to the expansion of coolant due to temperature.

(Aautomotive systems: 7-30Psi)

The other type of pressure is system resistance, this will reduce the flowrate of the pump.

Please view our flow curves within the Product Information section of the site.

Yes, the EWP controller will reduce the flow when the engine in warming up and then increase to 100% when at the target temperature.

NOTE: the maximum flowrate is determined by the systems resistance to flow.