aksman
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| posted on 3/12/20 at 04:19 PM |
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Electric Water Pump & Controller
I am going to use an electric water pump on an A Series 1275.
Are there any cheaper alternatives to the Davies Craig water pump?
Would an auxiliary water pump from a 2 to 3+ litre BMW / Merc etc. be powerful enough as an alternative?
Are there any cheaper alternatives to the Davies Craig Controller?
I am particularly keen on being able to auto-control the speed of the pump in relation to the varying water temperature, rather than a simple
thermostat.
Any info and suggestions woud be very welcome.
TIA
[Edited on 3/12/20 by aksman]
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lsdweb
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| posted on 3/12/20 at 05:12 PM |
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The Pierburg pumps (BMW etc) are very good and you can either buy a controller (Tecomotive TinyCWA) or you could make your own (Arduino etc). My
friend and I have made our own (well he has and I'm sort of copying him but using an ESP32 as it has built in CAN) and his works well. My plan
is to do exactly as you said and make the pump a touch more intelligent than something driven by a belt!
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Simon
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| posted on 3/12/20 at 06:08 PM |
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I think the Prius has an electric pump but I have no idea how it is controlled.
Also whilst looking at them on ebay, this ad came up with an electric pump which seen to have a huge list of cars
https://www.ebay.co.uk/sch/i.html?_nkw=303367589862
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aksman
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| posted on 3/12/20 at 06:41 PM |
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quote:
Originally posted by lsdweb
The Pierburg pumps (BMW etc) are very good and you can either buy a controller (Tecomotive TinyCWA) or you could make your own (Arduino etc). My
friend and I have made our own (well he has and I'm sort of copying him but using an ESP32 as it has built in CAN) and his works well. My plan
is to do exactly as you said and make the pump a touch more intelligent than something driven by a belt!
The Pierburg pumps or similar look promising. I hadn't thought that production cars were using electric water pumps 
The TinyCWA looks fab, but more £ than I want to pay.
Arduino etc... yes, i'm generally aware of these, but I had not thought of using them. A good Locost option!
Great info thanks
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steve m
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| posted on 3/12/20 at 06:52 PM |
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Only a suggestion, and i have no idea if it will work, or pump the correct volume or psi etc,
but what about caravan/motorhome electric water pumps
And they are 12v
steve
Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at
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Mr Whippy
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| posted on 3/12/20 at 07:17 PM |
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Not really something you want to skimp on. At best it could leave you stranded at worst cook your engine engine. Personally if the engine was designed
for a mechanical pump I'll stick with that as there hugely reliable and I don't feel the benefits of an electric pump justify changing to
one.
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nick205
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| posted on 4/12/20 at 09:01 AM |
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quote:
Originally posted by Mr Whippy
Not really something you want to skimp on. At best it could leave you stranded at worst cook your engine engine. Personally if the engine was designed
for a mechanical pump I'll stick with that as there hugely reliable and I don't feel the benefits of an electric pump justify changing to
one.
I'm with Mr Whippy on this. Stick with a proven mechanical pump (as the engine as designed with).
If you're building an all out race car or space packaging is a particular constraint then maybe change. If you do then stick with something
others have run and is therefore proven at the task. Overheated engines are not only time consuming, but usually involve more £££ and more people.
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CosKev3
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| posted on 4/12/20 at 10:35 AM |
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I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the
performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the
performance at zero pressure!
I'm now using a BMW Pierburg pump with the Tiny controller.
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aksman
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 posted on 4/12/20 at 10:49 AM |
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quote:
Originally posted by CosKev3
I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the
performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the
performance at zero pressure!
I'm now using a BMW Pierburg pump with the Tiny controller.
That's interesting.
The Davies Craig EWP80 quotes 80L/min which seems impressive on the face of it.
I haven't found any performance figures for alternative pumps yet, but it sounds like something to be aware of when making comparisons.
[Edited on 4/12/20 by aksman]
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aksman
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| posted on 4/12/20 at 10:53 AM |
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quote:
Originally posted by steve m
Only a suggestion, and i have no idea if it will work, or pump the correct volume or psi etc,
but what about caravan/motorhome electric water pumps
And they are 12v
steve
I've had a quick look at those types of pump and unfortunately they don't seem powerful enough
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aksman
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| posted on 4/12/20 at 11:05 AM |
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quote:
Originally posted by Simon
I think the Prius has an electric pump but I have no idea how it is controlled.
Also whilst looking at them on ebay, this ad came up with an electric pump which seen to have a huge list of cars
https://www.ebay.co.uk/sch/i.html?_nkw=303367589862
The Prius pump looks interesting.
There is a lot of info on Youtube for general uses and there are a lot of Chinese copies for £25 on Ebay - maybe prompted by it's popularity on
Youtube?
As you say, the other pump is widely used and available.
One of the key issues seems to be identifying single electric water pumps v auxiliary pumps and getting performance data for them.
Some of the DIY Youtube info suggests approx. 22L/min for the Prius.
[Edited on 4/12/20 by aksman]
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CosKev3
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| posted on 4/12/20 at 11:22 AM |
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quote:
Originally posted by aksman
quote:
Originally posted by CosKev3
I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the
performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the
performance at zero pressure!
I'm now using a BMW Pierburg pump with the Tiny controller.
That's interesting.
The Davies Craig EWP80 quotes 80L/min which seems impressive on the face of it.
I haven't found any performance figures for alternative pumps yet, but it sounds like something to be aware of when making comparisons.
[Edited on 4/12/20 by aksman]
At 7.5psi the EWP80 shows zero flow
https://daviescraig.com.au/media/2016/1596068015.EWPFlowChart24-07-19.jpg
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lsdweb
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| posted on 4/12/20 at 12:40 PM |
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I posted a chart of the flows of the Davies Craig and Pierburg pumps a while ago but somebody didn't like it and gave me hard time so I deleted
it! Shame as it was useful!
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lsdweb
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| posted on 4/12/20 at 01:01 PM |
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Here it is. There are other factors involved so don't take this as exact! I added the Meziere as this is the electric pump of choice for the
Type R lads (at a price!).
I have the CWA200.
Wyn
[Edited on 4/12/20 by lsdweb]
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lsdweb
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| posted on 4/12/20 at 01:17 PM |
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Fitted to my Civic.
[Edited on 4/12/20 by lsdweb]
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aksman
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| posted on 4/12/20 at 01:48 PM |
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Excellent info on the graph
The photos are useful - it's larger than I thought.
Interestingly there are a few negatives about the reliability of BMW EWP's on Youtube, but it seems to be Luddites
[Edited on 4/12/20 by aksman]
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craig1410
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| posted on 4/12/20 at 03:50 PM |
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quote:
Originally posted by CosKev3
quote:
Originally posted by aksman
quote:
Originally posted by CosKev3
I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the
performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the
performance at zero pressure!
I'm now using a BMW Pierburg pump with the Tiny controller.
That's interesting.
The Davies Craig EWP80 quotes 80L/min which seems impressive on the face of it.
I haven't found any performance figures for alternative pumps yet, but it sounds like something to be aware of when making comparisons.
[Edited on 4/12/20 by aksman]
At 7.5psi the EWP80 shows zero flow
https://daviescraig.com.au/media/2016/1596068015.EWPFlowChart24-07-19.jpg
Surely if the pump is operating in a pressurised coolant system where the pressure at the input to the pump is the same as the pressure at the output
then it doesn't make any difference to the flow rate? I mean there might be a small difference due to the slight overall increase in density of
the fluid but that would barely be noticeable. I think the graph here is showing the flow rate if the pressure on the output is higher than the input,
which it probably will be but nowhere near 7.5psi.
This is all based on my intuition so could be wrong but I'd be surprised.
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SteveWalker
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| posted on 4/12/20 at 06:12 PM |
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You're right. It is the back-pressure that the pump sees that matters, not the system pressure.
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craig1410
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| posted on 4/12/20 at 07:07 PM |
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quote:
Originally posted by SteveWalker
You're right. It is the back-pressure that the pump sees that matters, not the system pressure.
Yeah, backpressure is what I was thinking of. Once the backpressure reaches 7.5psi the pump will no longer be able to produce flow.
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aksman
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| posted on 4/12/20 at 07:24 PM |
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quote:
Originally posted by craig1410
quote:
Originally posted by SteveWalker
You're right. It is the back-pressure that the pump sees that matters, not the system pressure.
Yeah, backpressure is what I was thinking of. Once the backpressure reaches 7.5psi the pump will no longer be able to produce flow.
I think I understand
Is backpressure the same as resistance? The resistance that the pump has to overcome to move the water? The resistance that is associated with the
diameter of pipe, length of pipe run, quantity and type of fittings etc?
[Edited on 4/12/20 by aksman]
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Oddified
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| posted on 4/12/20 at 07:35 PM |
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quote:
Originally posted by aksman
quote:
Originally posted by craig1410
quote:
Originally posted by SteveWalker
You're right. It is the back-pressure that the pump sees that matters, not the system pressure.
Yeah, backpressure is what I was thinking of. Once the backpressure reaches 7.5psi the pump will no longer be able to produce flow.
I think I understand
Is backpressure the same as resistance? The resistance that the pump has to overcome to move the water? The resistance that is associated with the
diameter of pipe, length of pipe run, quantity and type of fittings etc?
[Edited on 4/12/20 by aksman]
In effect, yes.
I have a cwa100 for charge cooling dutes, very very good but not suitable for the main engine cooling.
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craig1410
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| posted on 4/12/20 at 08:03 PM |
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quote:
Originally posted by aksman
quote:
Originally posted by craig1410
quote:
Originally posted by SteveWalker
You're right. It is the back-pressure that the pump sees that matters, not the system pressure.
Yeah, backpressure is what I was thinking of. Once the backpressure reaches 7.5psi the pump will no longer be able to produce flow.
I think I understand
Is backpressure the same as resistance? The resistance that the pump has to overcome to move the water? The resistance that is associated with the
diameter of pipe, length of pipe run, quantity and type of fittings etc?
[Edited on 4/12/20 by aksman]
Picture it like this. If you fitted the pump into a U shaped piece of tubing that was full of water but open at both ends with those ends pointing
upwards. If you started the pump you would expect the water level to drop in one vertical leg and rise in the other. The difference in levels
represents the pressure difference across the pump. 7.5psi is just over 0.5 bar which is equivalent to approximately 5m of difference in the level of
the water in the two legs.
Another way to think of it is that the pump has a certain amount of “traction” just like a car tyre has only so much traction before it will start to
spin.
HTH
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number-1
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| posted on 4/12/20 at 09:17 PM |
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Ive read the above and the science is too much for me.....but....ive used Davies craig ewp on a single seater Yamaha engine BEC for track and it cured
an overheating issue i had (due to the extra 3 metres in cooling pipes needed) and also on a SC zetec engine and it worked a treat so would recommend
the davies craig ewp and controller
just my 2p worth
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CosKev3
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| posted on 5/12/20 at 01:58 PM |
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quote:
Originally posted by craig1410
quote:
Originally posted by CosKev3
quote:
Originally posted by aksman
quote:
Originally posted by CosKev3
I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the
performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the
performance at zero pressure!
I'm now using a BMW Pierburg pump with the Tiny controller.
That's interesting.
The Davies Craig EWP80 quotes 80L/min which seems impressive on the face of it.
I haven't found any performance figures for alternative pumps yet, but it sounds like something to be aware of when making comparisons.
[Edited on 4/12/20 by aksman]
At 7.5psi the EWP80 shows zero flow
https://daviescraig.com.au/media/2016/1596068015.EWPFlowChart24-07-19.jpg
Surely if the pump is operating in a pressurised coolant system where the pressure at the input to the pump is the same as the pressure at the output
then it doesn't make any difference to the flow rate? I mean there might be a small difference due to the slight overall increase in density of
the fluid but that would barely be noticeable. I think the graph here is showing the flow rate if the pressure on the output is higher than the input,
which it probably will be but nowhere near 7.5psi.
This is all based on my intuition so could be wrong but I'd be surprised.
The person that warned me about the flow drop under pressure had a Cosworth engine on a test bed with multiple probes fitted to the head.
They experienced hot spots in the head at higher temps which caused the head to go porous due to micro boiling.
The head was cut apart to investigate.
The cause was lack of flow from the Davies Craig EWP as they refitted the standard mechanical pump and it was ok running that.
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mgb281
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| posted on 5/12/20 at 05:04 PM |
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I was looking at this myself and have found out the following; that if your ECU has spare PWM outputs you can control an electric water pump from
there, the example I have been given is zero until 6c then 25% until 50c then 75% at 90c then 100% at 95c. Obviously you would adjust duty rates
according to your target temperature. Using your ECU or the Davies Craig controller enables you to do away with your thermostat, so the hot water will
leave the engine ang go straight to the radiator. The Davies Craig controller does enable you to allow both pump and fan to run for up to two minutes
after engine switch off to prevent heat soak. There is very little back pressure with a system like this due to the straight through design and
providing you have a header tank that keeps the system full then there is no head of water to pump..
As for reliability then you will not find thousands of owners on the forums complaining about failed pumps, just a few who would have complained about
a mechanical one as well.
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