Craig Davies electric water pump

RichardH · 03-08-07, 01:21 PM

Nice simple Q for you guys with a GTD and CD electric water pump..
Where have you mounted the Craig Davies controller for the electric water pump. They suggest in the cabin, but the sensor needs to be mounted in the thermostat housing, so it needs to be close to the rear bulkhead. Being a lazy bugger, and to save me time trying lots!? of different places, where have you mounted yours?

regards

Richard

MikeP · 03-08-07, 02:30 PM

Good question Richard. I also would like to know.
Cheers
Mike

DaveWharran · 03-08-07, 07:32 PM

Mounted mine (on ERA) just behind the dash at the passenger door jamb.

Some words of caution from a learning experience on my installation. I run mine as the temperature control for the engine. No mechanical thermostat. The Davies Craig controller is set to pulse voltage on and off when engine temperature is low. That provides a very fast warm up for the engine as the pump is actually stopped more than it runs. It only pulses which moves a small amount of the warming water out of the engine.
That's where the problem lies on a mid engine car. The water going into the radiator is cold-cold-cold- (because there is a lot of tubing and water between the engine and radiator, unlike a front engine/radiator combination) and then all the sudden, the 180-190 degree F water hits the cold aluminum radiator. The temperature shock expands the thin radiator tubes faster than the thicker radiator tanks and cracks the tube/tank connections causing a radiator leak. I had this happen to two Ron Davis radiators before figuring out what was going on.

My quick fix was to add a linear voltage control tied into the output of the DC controller to keep a minimum voltage on the pump at all times. I think I left it set to 2.5 volts at present. That allows the engine to warm at a decent rate and also moves the warming water to the radiator so it isn't temperature shocked. As the engine warms, the controller will raise the voltage above 2.5 volt as necessary.Note that the DC controller switches the negative lead going to the pump to control its voltage, not the positive lead.

Long term fix is to program the controller to better suit a mid engine car. I emailed Davies Craig with the problem but never received a response. I messed around with my own program in the PIC chip for a while, but other projects have pushed that temporarily to the side. So for now, the 2.5 volts minimum on the pump is working fine.

RichardH · 03-09-07, 02:19 AM

could that be achieved by fitting a 2.5 volt zener diode between the CD ground and earth?

Pete Fowler · 03-09-07, 06:37 PM

On a tangent, I did a bunch of research on electric water pumps for my Hayabusa powered Radical and given the racing demands of the pump, opted for a Mezier pump due to it's solid and robust design. I'd read some negative things about the DC pumps in high temperature and vibration applications.

I don't run any sort of regulator (since there's never a time I need to slow it down) but so far it's been dead reliable and they might have a design for a larger engine like a GT40.

http://www.meziere.com/index.php?pgName=Remote

Dave S · 03-09-07, 11:03 PM

I run a DC electric water pump on my DRB mounted up front near the rad.
I run it at full speed all the time and have a mechanical thermostate (80 degrees) in the normal position in the motor. I drilled a bipass hole in the thermostate to allow the water pump to flow. My Thermofan temp switch is mounted up front near the rad. My cars temp sits on about 82 when driving and 85 or so at idle. Another thing I like about EWP's is you can bleed your cooling system without your motor running.

RichardH · 03-10-07, 04:59 AM

two things i forgot to mention....
I have had to mount the pump in the radiator feed, not the return, as usual, due to space constraints and secondly the pump will be used as a boost (at least initially) to the normal water pump system. I am hoping that this will not affect warming up and thermal shock to the radiator.

Brett James-McCall · 03-13-07, 02:15 PM

Richard,
Can you send me photos. My Davies Craig 110 arrived from Oz whilst I was away on holiday. Thanks

Pete,
Interesting to hear your thoughts on the pump. I would have thought it was reliable, as ProDrive ran them on their LM Ferraris a few years ago.

Brett

Andrew E · 03-14-07, 08:22 AM

Hi Brett,
I ve just ftted a DC 110 LPM water pump and DC digital controller to my RF 40 and have found it to work well. My problem was if the car wasnt moving it would just get hotter and hotter as I suspected not due to air flow but insufficient water movement through the system. The electronic water pump has fixed that. I have removed the impeller frrom the standard 302 water pump and also the thermostat and letting the digitial controller manage things. I have mounted the controller in the cabin were it can be seen for visual check via the led lights of its status of operation. Took the car for a long run the other day at 40c temperatures not a hint of overheating even whilst at idle for lenghty periods. In terms of reliability only early days perhaps but all seems to work really well.

RichardH · 03-14-07, 03:19 PM

Here are some of my pics showing the position of the controller in the rear bulkhead. I believe that this compartment is not standard, and therefore would not suit everyone, but is admirably suited for positioning the controller and for running the cables into the engine bay and forward to the pump. The pump is mounted, as can be seen, just forward of the main front bulkhead and sits above the steering rack. As stated previously this is fitted into the supply pipe to the radiator, not the return, as recommended.
I hope this give you some ideas for your installation, but these photos are taken in its, as yet, incomplete set-up (I hate tie-wraps not trimmed back). My apologies for the pics being on their sides.