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Why an electric pump?
Nearly all cars still have mechanical water pumps - which is a bit strange, as electric pumps are more efficient in terms of the power they consume, and they can also match an engine’s cooling needs much more effectively. A mechanical pump is always a compromise. Belt or camshaft driven, its pumping rate varies directly with engine speed, so that at tickover in traffic jams it will barely pump sufficient water around the system, and at high revs it will be trying to pump too much, leading to wasted power and the risk of cavitation (disrupted flow caused by the pump trying to shift more coolant than the waterways, hoses etc will take).
The latest car designs are using electrical water pumps, as their reliability, availability and superior performance become understood. But the major advantages of improved cooling and higher engine efficiency (3%-5% fuel savings), or having more power available from a freer revving engine, are already available to anyone who wants to retrofit their car with a Davies Craig electric pump. Another major benefit is the ability of an electric pump to keep running after engine shutdown, to prevent the heat soak problems to which some engines are prone.
The Davies Craig range
The Davies Craig family of three pumps (EBP, EWP80 and EWP115) is suitable for a very wide range of applications. We sell them to owners (and builders) of:
- Older cars with thermosyphon-cooled engines
- Classic cars with less than adequate cooling
- Cars with a worn or broken mechanical water pump
- Kit cars
- Cars with tuned engines
- Racing cars
The pumps are also suited to a range of non-car applications:
- Motorcyles and Trikes
- Hovercraft
- Commercial vehicles
- Go karts
- Boats, caravans and motorhomes
- Even solar heating systems!
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Pump
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Flow litres/min
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Current amps
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Price
incl vat
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EBP
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15
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1.3
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£88.50
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EWP80
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80
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7.5
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£155.20
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EWP115
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115
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10
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£173.75
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The EBP or booster pump, with a maximum flow rate of 15 litres/min, is generally suited to thermosyphon- cooled cars and many motorbikes, go karts etc. It is ideal for improving the performance of car heaters in older cars, and is also happy to pump salt water for cooling smaller inboard boat engines. The EWP80 is suitable for the majority of car cooling applications with its flow rate of 80 litres/min, while its big brother the EWP115 has the extra capacity at 115 litres/min to cool very large engined vehicles, or high powered race engines. Click on the pump pictures for details. The pumps have proved themselves effective and reliable since their launch, and every pump comes with a 2-year warranty. If you’re not sure whether you need an EWP80 or an EWP115, have a look at the EWP comparison page. Or phone us to discuss it! All Davies Craig products carry a 2-year warranty.
Pump Control
There are two ways to control an electric water pump - with either an on/off switch, or with a speed controller.
If the electric pump is being used to assist an existing mechanical pump and provide extra coolant flow when the old pump can’t keep up, then a thermatic switch is the right control choice. These switches monitor coolant temperature and switch the pump on when the needle starts to rise above normal, just like the operation of an electric fan. Click on Switches for more details.
When the electric pump is the only pump it’s usually best to use a speed controller. This unit monitors coolant temperature as the engine warms up, and varies the pump speed (and hence water flow rate) to suit the cooling needs of the engine at that moment. Click on Pump Controllers for more details. And from July 2009 onwards the Davies Craig digital pump controller has been upgraded. It’s now a dual controller, and includes a facility to switch the electric fan on and off as well
In some situations, for example in a race car, the pump can be wired to run permanently, turned on with the ignition switch, or a separate manual switch. Various options are possible!
Please feel free to phone us on 01273 493343 to talk about your application.
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