When looking at electric water pumps what direction do you take?
Davies craig, EMP, take the market for the majority but both have stigma of reliability issues, I can't confirm any whispers as I have not had any issues with either. Now with more start stop and hybrid vehicles on the road there are more electric pumps released from the factory.
Factory pumps seam to offer more and feel a lot more robust and I got quite excited to give a BMW piersburg pump a run
Why would you run an electric coolant pump?
Well for me it gives me ultimate control over the coolant system, normally if a mechanical pump is fitted it can only run as quick as the engine goes however with electric I can have the pump at maximum speed while the engine is at idle or if the temperature is low I can choose to run the pump speed slow to help raise the temperature.
Another feature is power loss at the crank which would be seen from the mechanical pump however don't be fooled I still need to power this pump but releasing the pump from the belt may see a little more power but I am not convinced you would see it.
The water pump is a CWA200 from a BMW 118 and has the following specification;
* Pump duty point Q=7000 l/h / H=0,45 bar
* Ambient temperature -40°C ... +140°C
* Coolant temperature -40°C ... +128°C
* Voltage supply min. 10 V max. 18 V
* Power consumption P1 200 W
* nominal Current 16 A
* Quiescent current 6000 h
* Interface PWM
* Enclosure IP 67
If you wish to control using the vipec use the GP PWM and you will need to setup a control duty cycle too to give a good control. Using the Vipec I have had to add extra wires to the unit to control a relay and have an aux pwm for the water pump
The PWM frequency is 45Hz to 1100Hz
PWM operation is relatively typical
* 1~7% = Uncontrollable default to max speed
* 7~13% = 0 speed motor stopped
* 13~85% = 13% Minimum speed, 85 is maximum speed linear clime in rpm
* 85~99% = maximum speed
There is a tolerance of 1% so ideally a minimum speed would be 15% and maximum is fine at 85%, if you wish to stop the pump pick something like 10% to be far enough away from uncontrollable and minimum speed.
If you wish to only run the pump at maximum the you can run at 100% PWM which is technically just 12vDC
Running the pump at 100rpm makes filling the coolant system super easy as the header tank becomes a vacuum so as long as you can fill it fast enough you will be fine else it will suck air through once primed. The pump at 100% can just about open the thermostat which is less than ideal however you would not normally be running 100% unless you need to up the cooling and hence the thermostat would be open. (it only just opens as you can hear it fluttering)
Pin 1 Positive 12v
Pin 2 PWM signal
Pin 3 Not required
Pin 4 round
Wires, make sure you use the correct wires, I would suggest that the pump could reach a maximum of 15amps from my testing so make room for up to 30amps and add a fuse to the system. The PWM cable can be small 0.5mm^2 would be fine
For the connector I popped to BMW and ordered the correct connector and pins which made life much easier
If you wish to test or run the pump then connect positive to pins 1, 2 and ground to 4 and the pump will take a couple of seconds and will come to life.
Clearly if you wish to control the pump then you will want to use a PWM controller, I am using the Vipec and I have setup rules to control the pump based on rpm vs engine coolant temperature however I have several over riding conditions which will allow the pump to go to full speed this includes a small switch which allows me to bleed or fill the coolant system without the engine being on.
As for mounting the pump I do not have a lot of room and I took the AC delete pulley and removed all the idle bearing and bits not required until I was left with basically a mounting plate, I then made a strap bracket to fit the shape of the pump. I added anti vibration rubber round the pump and clamped it into place. It is worth noting that I cut off all the factory mounting lugs as they don't really fit for me. There are a couple of different versions of pump which would probably mount using the factory mounts.
Don't forget on the mini the coolant bypass hose is the small 20mm hose, I added a T piece at the bottom of the radiator to allow for circulation while the thermostat is closed.
Davies craig, EMP, take the market for the majority but both have stigma of reliability issues, I can't confirm any whispers as I have not had any issues with either. Now with more start stop and hybrid vehicles on the road there are more electric pumps released from the factory.
Factory pumps seam to offer more and feel a lot more robust and I got quite excited to give a BMW piersburg pump a run
Why would you run an electric coolant pump?
Well for me it gives me ultimate control over the coolant system, normally if a mechanical pump is fitted it can only run as quick as the engine goes however with electric I can have the pump at maximum speed while the engine is at idle or if the temperature is low I can choose to run the pump speed slow to help raise the temperature.
Another feature is power loss at the crank which would be seen from the mechanical pump however don't be fooled I still need to power this pump but releasing the pump from the belt may see a little more power but I am not convinced you would see it.
The water pump is a CWA200 from a BMW 118 and has the following specification;
* Pump duty point Q=7000 l/h / H=0,45 bar
* Ambient temperature -40°C ... +140°C
* Coolant temperature -40°C ... +128°C
* Voltage supply min. 10 V max. 18 V
* Power consumption P1 200 W
* nominal Current 16 A
* Quiescent current 6000 h
* Interface PWM
* Enclosure IP 67
The PWM frequency is 45Hz to 1100Hz
PWM operation is relatively typical
* 1~7% = Uncontrollable default to max speed
* 7~13% = 0 speed motor stopped
* 13~85% = 13% Minimum speed, 85 is maximum speed linear clime in rpm
* 85~99% = maximum speed
There is a tolerance of 1% so ideally a minimum speed would be 15% and maximum is fine at 85%, if you wish to stop the pump pick something like 10% to be far enough away from uncontrollable and minimum speed.
If you wish to only run the pump at maximum the you can run at 100% PWM which is technically just 12vDC
Running the pump at 100rpm makes filling the coolant system super easy as the header tank becomes a vacuum so as long as you can fill it fast enough you will be fine else it will suck air through once primed. The pump at 100% can just about open the thermostat which is less than ideal however you would not normally be running 100% unless you need to up the cooling and hence the thermostat would be open. (it only just opens as you can hear it fluttering)
Pin 1 Positive 12v
Pin 2 PWM signal
Pin 3 Not required
Pin 4 round
Wires, make sure you use the correct wires, I would suggest that the pump could reach a maximum of 15amps from my testing so make room for up to 30amps and add a fuse to the system. The PWM cable can be small 0.5mm^2 would be fine
For the connector I popped to BMW and ordered the correct connector and pins which made life much easier
If you wish to test or run the pump then connect positive to pins 1, 2 and ground to 4 and the pump will take a couple of seconds and will come to life.
Clearly if you wish to control the pump then you will want to use a PWM controller, I am using the Vipec and I have setup rules to control the pump based on rpm vs engine coolant temperature however I have several over riding conditions which will allow the pump to go to full speed this includes a small switch which allows me to bleed or fill the coolant system without the engine being on.
As for mounting the pump I do not have a lot of room and I took the AC delete pulley and removed all the idle bearing and bits not required until I was left with basically a mounting plate, I then made a strap bracket to fit the shape of the pump. I added anti vibration rubber round the pump and clamped it into place. It is worth noting that I cut off all the factory mounting lugs as they don't really fit for me. There are a couple of different versions of pump which would probably mount using the factory mounts.
Don't forget on the mini the coolant bypass hose is the small 20mm hose, I added a T piece at the bottom of the radiator to allow for circulation while the thermostat is closed.
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