Fan and Water Pump Controller

[Chris]

I'm having trouble with the Davis Craig Digital Controllers. The first one was bad straight of the box and was replaced with no hassle. Now I've done 1800 miles and the second one is on the blink and won't function. Caused me an issue at the weekend and I had to be recovered.

Is there an alternative controller that others have used? I don't have an ECU and I don't really want to re wire too much stuff but I have no faith in these DC controllers now.

And yes, I've checked all my wiring, fuses and changed the fan relay, it still doesn't work! Controller boots and then goes blank.

 

[Randy Folsom]

I bought the Tiny CWA from Tecomotive. I have not installed it yet, so can’t speak to how well it works.

Tecomotive - tinyCWA

Tecomotive develops and sells unique electronic devices for use in vehicles of all kinds.

www.tecomotive.com

 

[Chris]

I bought the Tiny CWA from Tecomotive. I have not installed it yet, so can’t speak to how well it works.

Tecomotive - tinyCWA

Tecomotive develops and sells unique electronic devices for use in vehicles of all kinds.

www.tecomotive.com

Thanks for that. That's an option for sure. maybe I should switch the whole system for a Pierburg 400 and Tiny controller

 

[Randy Folsom]

Thanks for that. That's an option for sure. maybe I should switch the whole system for a Pierburg 400 and Tiny controller

I am going with the Pierburg 400 as well. I saw a YouTube that compared the CD to the PB and the PB won. The DC flow rates are measured with no pressure whereas the PB includes pressure in their measurement. I plan to tuck the pump inside the sponson under the four link mount.

 

[Howard Jones]

Chris, Where is the controller located? In the engine room or in the cockpit? I suspect they won't like engine room heat. Mine is mounted in the cockpit. No AC and I run the car in Texas summers as a track car. It has a few thousand miles on it (all track miles) and no problems.

By the way, the pump will run at constant speed if you simply connect it to 12v. I have a jumper made up so I can disconnect the pump plug from the controller and plug it into a constant 12V source as an emergency backup.

The plan for controller failure is to unplug the controller from the loom, disconnect the pump with its plug at the pump, and then plug the pump into the jumper cable that is connected to the 12v system.

 

[Randy V]

I set my electric water pump to run constantly and had a thermostat to bypass (either partially or fully) the radiator…. It’s darned difficult to beat simplicity..

 

[Brian Kissel]

Just a heads up. I just went to order a spare CWA400 Pierburg direct from Germany. The old version is no longer available.
The new version is not available for at least 90 days, and it is no longer able to run off their Tiny CWA controller.

Pierburg CWA400 Water Pump LIN

- - - Attention! - - - Since around March 2024, the CWA400 only supports control via LIN bus . Pierburg is now installing new internal…

tecomotive.com

Regards Brian

 

[Randy Folsom]

Just a heads up. I just went to order a spare CWA400 Pierburg direct from Germany. The old version is no longer available.
The new version is not available for at least 90 days, and it is no longer able to run off their Tiny CWA controller.

Pierburg CWA400 Water Pump LIN

- - - Attention! - - - Since around March 2024, the CWA400 only supports control via LIN bus . Pierburg is now installing new internal…

tecomotive.com

Regards Brian

Might need to start looking in salvage yards.

 

[Brian Kissel]

I already have one, and just wanted to get a spare while the dollar is somewhat favorable. I might buy one of the knockoffs to try on my run in stand. At least using it on my test stand, I won’t be stranded miles from home. I didn’t plan on using the Tiny CWA control anyway so I’m not out anything there either.

Regards Brian

 

[Paul Proefrock]

Brian,
It appears Pierburg now offers two styles of the CWA400 pump. One is prefixed "LIN" (Linear?) the other is "PWM" We use the PWM version which is still available per their site this evening CWA400PWM

Paul

 

[Brian Kissel]

THANKS for that Paul. Tuesday they weren't available, and now suddenly they are. Going to order me a spare.

Regards Brian

 

[Scott]

One is prefixed "LIN" (Linear?) the other is "PWM"

Paul, LIN (Local Interconnect Network) is a low-cost single-wire serial protocol. It seems that OEMs are increasingly using this for communications with simple devices because it reduces the number of wires and is less expensive than CAN bus. For example, the PWM version of the CWA400 requires two wires (Signal-PWM and Signal-Ground) whereas the LIN version requires only one.

I'm in the process of designing my harness and MoTeC ECM/PDM configuration. I already have a couple of LIN devices and I will have three unused LIN wires (nose, cockpit and tail) for future expansion. I assume that most modern ECUs offer LIN communications and that there are also standalone LIN controllers.

 

[Randy Folsom]

I have a question regarding flow regarding the Pierburg CWA400 in my RCR40.

I am considering mounting it up front, but to minimize bends, the input would be a straight shot from the upper coolant tube in the spine and the output would flow directly into the radiator.

I worry the high pressure surge going directly into radiator might cause problems.

Is that a real concern?

 

[Ian Clark]

Hi Randy,

The EWP (electric water pump) has to be near the engine and as close the floor as possible.

There is room in rear portion of the RCR sill boxes for a remote pump, typically one side is used for the battery.

Packaging can be a challenge as you've probably found out

The temperature sensor for the EWP must be in the intake manifold crossover passage. The control of the radiator fan(s) can be sensed from the radiator.

If the EWP controller has a soft start mode or continuous slow minimum speed setting and NO thermostat is in the intake manifold there should be no issues with high pressure surge affecting the radiator.

If you have a properly plumbed and temperature sensed EWP controller with variable pump speed control, I see no need for a thermostat on the engine, however a mechanical waterpump requires a whole different set of component and layout considerations.

If you're running dual fans and A/C you might consider having one fan controlled by the A/C system and other fan by the waterpump controller.

Quality build btw!

Cheers
Ian

 

[Randy Folsom]

Hi Randy,

The EWP (electric water pump) has to be near the engine and as close the floor as possible.

There is room in rear portion of the RCR sill boxes for a remote pump, typically one side is used for the battery.

Packaging can be a challenge as you've probably found out

The temperature sensor for the EWP must be in the intake manifold crossover passage. The control of the radiator fan(s) can be sensed from the radiator.

If the EWP controller has a soft start mode or continuous slow minimum speed setting and NO thermostat is in the intake manifold there should be no issues with high pressure surge affecting the radiator.

If you have a properly plumbed and temperature sensed EWP controller with variable pump speed control, I see no need for a thermostat on the engine, however a mechanical waterpump requires a whole different set of component and layout considerations.

If you're running dual fans and A/C you might consider having one fan controlled by the A/C system and other fan by the waterpump controller.

Quality build btw!

Cheers
Ian

Ian,

As always, your guidance is very helpful. I had not thought about a fan being controlled by the A/C. I will add that to my wiring. Rather than controlling one fan, I may try configure it so the A/C overrides the radiator temperature sensor so that both fans are on if the A/C is on. I had not thought about a separate thermostat for the radiator. That makes a lot of sense so I am adding that to my wiring as well.

I have determined that I will figure out a way to mount the pump near the engine, and as low as possible. John Howard stopped by today and he provided the same advice.

I am pretty sure the TinyCWA controller can be configured to always be on when the engine is at operating temp so surging should not be an issue, especially since the pump will not be surging into the radiator. The TinyCWA has a temp sensor that plugs into the crossover passage, so I will not be installing a mechanical thermostat in the loop.

Cheers, Randy