Davies Craig Controllers

Davies CRaig have a 'newer' digital version of their controller out. Does anybody know if this is generally an improvement over the original controller?

The reason I ask is that I may be able to get one of the original controllers cheap(ish) from someone and wanted to understand the benefits of the digital vs. the old. My plan is to run only a DC pump (I have the heavier duty version); I know many people will tell me (or suggest) to run the pump as an auxillary, but I am going to try just the electric route at first.

Brett

Hi Brett,

I am running the digital water pump controller in my car. Works fine. On warm up cycles water out of the engine in batches to progressively warm the water up. Controller is programable to set cut in point and for full flow and temperature control. I've mounted the controller in the cabin so I can see the stages of operation the pump is at. I am running the 110ltre per minute pump with impeller removed from the original pump and no thermostat. Another feature I like is the pump continues to run after shut down to assist to remove heat soak from the engine for about 2mins.

Andrew E

Photos:

Hi Brett -

Glenn Mason has one on his Southern GT and it seems to work well at temp but still possibly not ideal during warm up. I think it has something due to the length of pipework to rad but basically, the motor can initially get quite hot and then be hit with a slug of cold water, whilst also hitting the rad with a large slug of hot. There are reported cases of thermal shock damage to alloy rads I believe.

I'm working on an add-on for Glenn, that monitors the engine temp on power on and if below a certain temp it takes control of the pump, running it at a pre-selected rate, until a specific temp is reached, at which point control is returned to the main DC controller. If the motor is already warm when the ignition is powered on, then control passes directly to the DC unit.

It uses a PIC micro and Mosfet PWM motor control and will also interface to the fans on cool down.

Give Glenn a call to discuss and if you've not got his number, pm me and I'll forward your details to him.

Hmm - posted about same time as Andrew but interestingly his system works just fine.....

I'm wondering if the failures of the earlier controllers could have been caused by the current draw of motors/pumps not of Davies Craig manufacturing?
All of the DC water pumps I looked at some time ago flowed far less than some of the other pumps on the market.
Draw more amps through a circuit that what it was originally designed for would certainly lead to an earlier death..

Hi Paul,

Sounds like the system in Glenn Masons car is the early version? Your description of your add-on for Glenn is what the controller I have does on warm up. BTW my pump & controller are both Davies Craig units. On my car there is three temperature senders, Bosch sender for the Motec (most accurate controls thermatic fans), Sender for the dash (gauge not accurate over reads) and a thermister unit which is for the electronic water pump which appears to be aligned to the temperature readings from the Bosch sender.

It has been suggested that I could ditch the Davis Craig controller unit and have the motec control the electronic water pump to replicate the same functionality (cycling on warm up & run on after powering down) as the Davis Craig unit does, is that possible Paul?

Andrew E

Hi Andrew -

Glenn definately has same controller and has DC pump, (larger version). He has used the car quite a lot and whilst I'm not aware of him having any specific problems, I think he just wants it to work how 'he' wants it to.

He does not have Motec (on Webers) so that would not be an option but for those that have, I'm sure that would be achievable. There are inputs/outputs configurable for all manner of functions, including Fan control etc etc. There are PWM outputs so there could be a duty cycle controlled signal configured for pump control, that is related to the temperature BUT - I definately think you would need to use an external Mosfet cct to actually interface to the pump. I'm not sure what the current capability of the Motec units for PWM is, but interfaced you can run as much as you like... Having a very low internal resistance, selected Mosfets will handle high currents, 30A+ with ease...

One issue using the Motec though is I don't think you could have differing 'programs' for PWM output for the various stages of engine warm up. Might be possible but I've not looked into it.

Anyone else on here know? - Ross?