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Electric water pump controller?


Stray

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Hello All, 

 

I’ve been dreaming of an electric water pump for years. 
 

No real reason other than I like the idea and want one. The existing mechanical piece does a fair job but the electric ones have several advantages: 

 

1. Can run them after shutdown to avoid heat soak 

2. They can be configured run at an optimal speed and aren’t forced to run at engine speed. This means they don’t cavitate at high revs and aren’t hopeless at idle

3. Electric pumps can improve MPG and apparently release some (very little!) extra power as they’re not run by the engine

4. They offer better control over cooling if you can get a decent controller

5. Better coolant flow if you can delete the thermostat

 

I’ve decided to try the Davies Craig Electric Booster Pump 40 (EBP40). It pushes 37 litres per minute which is more than enough as loads of litre bikes run fine on their 15 lpm pumps. The EBP40 is a wonderful brushless motor rated at 100,000 hours. 
 

My problem is the controller - can’t find one to work with the EBP40! 
 

Davies Craig’s controller is designed to run their bigger car pumps. The smaller booster pumps apparently don’t have a high enough starting voltage to trigger the controller so Davies Craig don’t support their use. 
 

Davies Craig say best thing is to leave the mechanical thermostat in place and run the EBP40 at full speed all the time. Thermostat will open & close to control cooling. 
 

But I don’t like that idea for 4 reasons: 

i. The stock thermostats are notoriously fragile and a bitch to replace. It would be worked hard by the EBP and will likely fail quickly

ii. EBPs don’t like pushing against a head of pressure. Pushing against the thermostat isn’t ideal, neither when closed nor open

iii. Removing the thermostat opens the pipes to full bore giving less restriction/turbulence/pressure

iv. Need the controller to get full control over cooling system (running after shutdown, choosing optimal operating temp etc) 

 

Apparently Pulse Width Modulation (PWM) is the best way to control these things. 
 

So does anyone have any ideas or experience with these? Any advice? How do I control mine without a thermostat? 
 

Know my way around a spanner but electrics are a nightmare. Programming controllers is an absolute black hole in my knowledge. 
 

All advice gratefully received. 
 

Stray

 

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You need to define operating parameters before trying to implement controller algorithm.

 

PWM is only needed if you're running pump full-time. Then it would run 100% duty cycle when hot and say... 10% when cool.

 

Doesn't need to be that complicated. Can use thermoswitch to control motor. Turns on at X-degrees. Turns off at Y-degrees.

 

Take a look at how Porsche/Mercedes control turbo water-pumps.

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6 hours ago, Magneto said:

So the thermostat. Tstat is a valve that open full cooling circuit once bike warmers out. Would you like to control the warm up with pump flow instead? 

Correct!

4 hours ago, DannoXYZ said:

You need to define operating parameters before trying to implement controller algorithm.

 

PWM is only needed if you're running pump full-time. Then it would run 100% duty cycle when hot and say... 10% when cool.

 

Doesn't need to be that complicated. Can use thermoswitch to control motor. Turns on at X-degrees. Turns off at Y-degrees.

 

Take a look at how Porsche/Mercedes control turbo water-pumps.

Good thinking Danno but it’s not that simple. Pump needs to circulate coolant even when cold or I could end up with hotspots around the cylinders. 
 

And simply turning the pump on at X degrees is a bit crude. Needs PWM to ramp up circulation gradually as it’s needed. No point running a pump full throttle if the temp is only just coming to operational levels. Or having it completely off when temps are just below X. 
 

Also, the controller would allow me to fine tune the pump and run it after shutdown. A simple switch wouldn’t cut it. 

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What is measurable result do you want to achieve?
As in, how will you know electric system is working better than stock system?

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Stray,

 

I have two points you may want to consider:

 

1. what is the amperage draw of the pump? If you are running this pump full load you will be loading your stator which would increase more drain on a fragile electric system and sucking the minimal bhp you state you could gain from fitting it. This would be even more drain on the system when the fan is operating as well.

 

2. why would operating the pump on full head cause issues for the thermostat? The stat is mechanically strong and operating on a closed head is not an issue for it. The main issue from failure that we see is the wax unit itself which is internal of the stat itself. I have never seen in either a car or bike failure of a stat from water pressure?
 

I have a Davies Craig electric fan controller fitted to my bike and have it switch on at 97 degrees C and it then switches off at 92 degrees C. The thermostat pick up point to the controller is in the main radiator hose that comes from the stat to the primary radiator.

 

I do seem to remember that someone on the site had fitted an electric water pump to their bike in the past but no further details on how it ran.

 

I will be interested to see how this install goes so please show pics during the build and a report on the outcomes of cooling and electrical loading once complete.

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Bad vibes about this!

Existing system is probably the simplest most reliable system you could have for coolant movement and temperature regulation.

 

What gain can you make from an elecric pump? It won't make the bike run cooler on a stinking hot day or in stop start traffic. Air flow through the radiator core and air temperature are the limiting factors for heat dissipation.

 

As for fuel savings and power increase, maybe one drop in the ocean, if anything!

Irrespective of how reliable the electric pump is, you've now introduced other issues, the reliability of the controller and all associated wiring and connections, and as mentioned additional loading on R/R and stator could be a factor.

 

Sorry, but firmly believe this would achieve zip and be detrimental to overall reliability. Complexity without rock solid engineering is always inversely proportional to reliability. But, as always YMMV.

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8 hours ago, Marooncobra said:

Stray,

 

I have two points you may want to consider:

 

1. what is the amperage draw of the pump? If you are running this pump full load you will be loading your stator which would increase more drain on a fragile electric system and sucking the minimal bhp you state you could gain from fitting it. This would be even more drain on the system when the fan is operating as well.

Marooncobra, it’s only 4.6A at full tilt. That’s less than the fan! Also, the stator pumps out full amps all the time. Any extra is shunted to the regulator and dissipated. This won’t tax the electrical system - simply using up power that would otherwise be scrapped. 

8 hours ago, Marooncobra said:

 

2. why would operating the pump on full head cause issues for the thermostat? The stat is mechanically strong and operating on a closed head is not an issue for it. The main issue from failure that we see is the wax unit itself which is internal of the stat itself. I have never seen in either a car or bike failure of a stat from water pressure?

Sorry if I wasn’t clear. It’s the pump that doesn’t like a full head of pressure and might fail sooner. Thermostat doesn’t care about that but causing it to open-close-open constantly might also compromise the thermostat. 

8 hours ago, Marooncobra said:

I have a Davies Craig electric fan controller fitted to my bike and have it switch on at 97 degrees C and it then switches off at 92 degrees C. The thermostat pick up point to the controller is in the main radiator hose that comes from the stat to the primary radiator.

Is your Davies Craig controller reliable? 

8 hours ago, Marooncobra said:

 

I do seem to remember that someone on the site had fitted an electric water pump to their bike in the past but no further details on how it ran.

I believe Mohawk and the Phantom have electric water pumps. Mohawk has same issues as me with the controller so I’m guessing he still runs the thermostat. 

8 hours ago, Marooncobra said:

 

I will be interested to see how this install goes so please show pics during the build and a report on the outcomes of cooling and electrical loading once complete.

Absolutely...if it ever gets off the ground. Without a good controller this is stillborn. 

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9 hours ago, squirrelman said:

deleting thermostat is not a good idea, nor is an electrick water pump.

 

 

8 hours ago, Grum said:

Bad vibes about this!

Existing system is probably the simplest most reliable system you could have for coolant movement and temperature regulation.

 

What gain can you make from an elecric pump? It won't make the bike run cooler on a stinking hot day or in stop start traffic. Air flow through the radiator core and air temperature are the limiting factors for heat dissipation.

 

As for fuel savings and power increase, maybe one drop in the ocean, if anything!

Irrespective of how reliable the electric pump is, you've now introduced other issues, the reliability of the controller and all associated wiring and connections, and as mentioned additional loading on R/R and stator could be a factor

 

Sorry, but firmly believe this would achieve zip and be detrimental to overall reliability. Complexity without rock solid engineering is always inversely proportional to reliability. But, as always YMMV.

Appreciate your reservations, chaps. Honest feedback always welcome. 

Few points to note: 

1. Existing system isn’t great as it’s a compromise. It has to turn the water pump enough at idle to cool the bike at the lights. But does it do so? If you idled you’re bike for 30 minutes would it run nice and cool? Mine wouldn’t! Conversely, if it cools enough at idle imagine how fast the coolant is flowing at 10,000rpm with air rushing through the radiator at 100mph! Existing system goes from feast to famine whereas electric only pumps what’s needed all the time. Much more elegant. 
 

2. you’re right that the rad and fan are big parts of the cooling equation. I’m not ditching those. But having a more elegant water pump surely must be better? Those which fitted these pumps (without a controller) often post they can’t get the bike up to temperature, even when revving it for long periods. One of our lads said he couldn’t get the bike hot enough to engage VTEC on his 6th gen. Despite this, good MPG gains have been reported. 


You’re right about introducing complexity. Controllers and pumps can fail. Remember, however, these EBPs run for hundreds of thousands of miles in VWs, Mercedes and other makes every day. Electric Vehicles use these as the only method of cooling with great success. And our brothers run fuel controllers like Power Commander or Rapid Bike day-after-day without issue. 
 

Equally, mechanical water pumps do fail, same as any other part. There are a few threads on here about exactly that. I believe these aren’t available from Honda any more so members might be interested in an alternative. 
 

An electrical system offers control based on demand. That’s got to be better than an arbitrary system governed by engine RPM. I’m just trying to find a way to make it work. 

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10 hours ago, DannoXYZ said:

What is measurable result do you want to achieve?
As in, how will you know electric system is working better than stock system?

Good question, Danno. 
 

I guess if the bike runs at optimum temperature (at speed or at idle) and warms up properly it can be deemed to work.
 

You can say the stock system achieves all that already but it relies on the thermostat to regulate the arbitrary RPM-based water pump. 
 

If I get some extra MPG and a smidge of power that’s a bonus. Ability to run pump after shut down to avoid heat soak is also good. 
 

I’d like to improve coolant pumping and eliminate the thermostat for smoother flow. Will improve cooling in traffic and the odd track day. 
 

Most controllers have a light to indicate system failure. And there’s always the temp gauge as a last resort. I also believe the 5th gen ECU shuts down when dangerous temps are reached (please correct me if wrong?). 

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I do indeed run a Davies Craig 15L/min booster pump & had the same  issue, their controller does NOT work with these low draw pumps. No idea why its an electrical controller & I've never seen a switch that was load dependant!  So I had to keep the thermostat & thus had to create a  bypass circuit similar to the original pumps to stop the pump pushing against a static pressure head. 
 

Unlike the std pump which has to be tuned to a halfway efficiency where it works OK at all revs, the electric one runs at one speed only. So its great at high engine speeds, but very efficient at low engine revs & does cool better in slow speed hot running conditions. Don't know if it saves power, but it does allow me to stop the engine & keep the pump running when the bike is really hot. 
 

Last year I made a trip to London, it was 35c ambient temp & 20mph street speed zones & whilst the fans were on a lot of the time the bike did not overheat. On the other hand sitting in the plume of heat from the rads, I did ☹️
 

IIRC the Davies Craig controller, has a temp sensor & before it reaches a useful temp it does timed pump bursts. So cold start, it pumps for a few seconds, pause wait X seconds & repeats until it gets heat on the sensor, then it switches on/off or runs continuously based on the coolant temp.
 

It should not be hard now to create  a controller to do this, Rasberry Pi etc, switching a solenoid or a PWM to provide slow coolant flow initially, then more as temps dictate. If you have an ambient reference sensor, then you could set parameters based on air & coolant temps, even better if you had a 3rd channel giving coolant return temp, with some logic you could adjust flow for best cooling at any speed/air temp, a bit like AFR auto tuning ! The aim being to keep the cylinders at a constant temp in use, thus avoiding thermal stress & associated wear. 
 

All vehicles are a compromise of function/cost/longevity. You may or may not be able to tune elements to better suit yours needs, either way its fun trying 👍


One advantage of the electric coolant pumps efficiency is I can run a leaner mixture, currently 14.2/1 AFR on my RBRacing which returns better mpg with no loss of power or throttle response. The VFR runs pretty rich in stock form. 
 

As always YMMV

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Interesting read. Some points worth to mention, higher running temperature for combustion engine the better from efficiency point of view. Overheating problem or rather current temperature limits are due to material limitation. Similarly from heat transfer point of view, higher delta T, temperature difference b/w ambient and op temperature more heat transfer. Turbulent flow is better for heat transfer than laminate flow. Pumps dead head occur with blocked discharge, there is no such situation in small loop with thermostat closed. 

Without small loop will be very difficult for engine to reach operational temperature at low ambient temperatures. Wax thermostat valves are extremely reliable, most issues are due cooling media aging and following corrosion. 

Lastly issues of overcooled engines are well know from marine outboards, premature wear, carbon build up and etc...

I am surprised to read about overheating problems on 800 models. Looks like the system layout is a compromise and rads are to small. 

1200 with its classic system layout, huge centrally mounted single radiator has no such issues. There is even oil to water cooler that adds load to the primary cooling system. All runs fine even in the tropics.

 

 

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I remember in the day when the 5th gen came out, Honda had commentary about how great relocating the rads to the sides was - allowed to shorten up the wheelbase, improve handling and centralized weight distribution - blah, blah, blah.  Then on the 8th gen the commentary switched to how great it was to relocate the rads to the front (didn't think we were watching, did 'ya, Honda??)  :ph34r:  Anyway - it seems that the side rad set up has caused a lot of owner anxiety about temps - but in my time here I can recall just one post where the owner actually had the temp hit the number (250F?) where the ECU shut down the motor.   I can't ever recall a post where damage occurred due to over heating.  Not that they don't run hot - I've had my own share of WTF?? moments.  To me, the biggest downside to them is their vulnerability to a tipover.  Looking at used ones offered on ebay, they're frequently bent or beat up.  Getting the rad centralized inside the profile of the bike's frame offers a lot more protection to a very fragile part of the bike. 

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Thanks for chiming in, Mohawk - I was hoping you’d join the party! 
 

Like you, I don’t understand how Davies Craig's booster pumps are too small to register on their controller. Unfortunately I don’t have the skill/knowledge to figure it out myself. 
 

Was hoping someone would have a solution but no one appears interested. Even spoke to a few auto electricians locally who just blink at me with a vacant look. Should I be talking to programmers instead? 
 

Here’s the email response I got from Davies Craig about how to control their EBP40 (I also asked if their older controller would work since the new one doesn’t): 

 

Thanks for contacting Davies Craig regarding the EBP40 and the EWP controller.

 

The operation of the older controllers and #8002 remains unchanged.

This does mean that the EBPs are not suitable for use with the EWP controller. This is because the start-up voltage of the EBPs is around 6VThis means the we cannot guarantee the EBP will work under these conditions so we do not recommend using an EBP with the controller. NOTE: the EBP23 and EBP40 may work with the controller but there is no guarantees on correct operation.

 

When it comes to controlling EBPs you can always use a Solid state relay and an aftermarket ECU with PWM outputs.

Apart for that there is not really any other automated flow control option for the EBPs that I know of.

 

However, when it comes to temperature control on small capacity/power engines like those used on bikes I have found the best way to manage temperature is with a bypass thermostat.

 

The best way to implement this is to install an aftermarket inline bypass thermostat housing (similar to below) in the top hose.
 

76C9A14D-C710-44BA-B06D-9ABFB9F1E3FA.jpeg.e52491cd3ad8c9ec123f23c052779b7d.jpeg

 

The bypass line of the thermostat needs to be routed to the EBP inlet and the thermostat needs 2 x 3mm holes drilled into it.

 

The EBP is then ran continuously off the ignition and b using the Bypass thermostat, there will always be constant circulation though the engine, this will help decrease warmup time.

 

Once at operating temp the coolant will then flow through the radiator to help maintain temperature.

 

 

Regards

 

 

 

 

<image002.jpg>

 

Alex Hockey

Product Engineer

 

So what do you guys think? Will this delay warmup too much? It won’t be as quick as stock but will provide better cooling at full temp. I think? 
 

Or I could just use the existing bypass and hoses to mount the EBP40 in stock position. 
 

Both options require a thermostat. Would rather have an electric controller. 

Stray

 

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4 hours ago, Kiwiwannafly said:

Watching the temp rise from a 'normal' of 77-78C to 95+ sitting in traffic in summer is a bit of a anxiety builder, but never has seemed to cause any issues.

I just prefer hot warning light and no gauge. Actual temperature display is TMI. From time to time I would caught  myself watching temperature fluctuations and robbing time from actually important job of staying alive. 

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So I’ve done some reading on solid state relay (first stop - what the heck is one of those?). 
 

Turns out most of these work from 3v-upwards. They require around 1.6v to saturate/actuate the switch. This means a motor with current draw of, say 6v, only has about 4.4v to operate. 
 

Loads of forums say how motors drawing around 3-5v don’t work properly with solid state relays. They only seem to run at half power. 
 

Electric motors are best at fully on or fully off. Partly on creates resistance/heat and burns out the motor faster. That’s why Davies Craig use Pulse Width Modulation, which powers the motor fully on for intervals (pulses) rather than graduated power. 
 

I’m starting to understand why their controller isn’t suitable to the brushless low-draw pumps. 
 

Every day is a school day. But not sure where to go from here. 
 

Stray

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Stray

 

The Davies Craig controller is very reliable and I have had it fitted for about 4 years. It can operate two 40amp circuits which are switched by relays and are part of the controller. You can set the temp to switch on the first relay from 35 - 110 degrees C and on activation the second relay energises after 10 secs. Once energised both circuits will not switch off until the temp has dropped by 5 degrees C from the original set point. The unit itself is self contained and well constructed. 
 

When I first installed it I did try and mount a second fan to the primary radiator and get that to start first with the fitted fan to come on 10 secs later. However, I found by fitting the second fan it reduced the natural flow of air across the primary radiator  when riding at normal speeds and the temp actually increased by 3-4 degrees. Go figure!!

 

My ideal would be to find a radiator matrix that would fit between the two side radiators so you would at least get some traditional forward facing cooling, but I would like to think the Honda gurus thought of that during the design and decided it wasn’t a good idea!
 

Further details can be found here on the controller
 

https://daviescraig.com.au/product/digital-thermatic-fan-switch-12v-24v-0444/digital-thermatic-fan-switch-12v-24v-0444 

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There is nothing wrong with side mount rads, they are efficient. I had a chat a few years ago with the designer of the Vyrus racer. Due to using a swingarm frontend they could not mount traditional rad. So mounted side mount rads in the belly pan. I queried their efficiency & was informed they actually made them smaller during testing because they were more efficient than they had calculated. Plus they save a lot of drag & improve the engines thermal efficiency. 
 

Traditional rads are not very aero dynamic, the last plane with a barn door rad was of WW1 vintage. They also take cool air from in front of a vehicle & make it warm, THEN it flows over & through the bike not really cooling the engine much at all, that raises the engine temp which means you need a bigger radiator to make sure the coolant returns at a low enough temp to cool the engines insides & its outside from the rads own heat soak. 
 

Side rads avoid reheating the engine with its own waste heat. They are low drag, but less efficient at low speeds unless angled off the vertical to allow hot air to rise naturally through them. Thats why Vyrus has them in my the angled sides of the belly pan, when moving air enters between them & passes from inside to outside. When slow or static the air flow reverses flowing from outside to inside & out through a gap between engine & belly pan. That setup is fine on a race bike, as they don't do slow speeds, only stop or fast!  On a road bike they would be best mounted out at the bottom so the airflow was always inside to out regardless of speed. Honda mounted them vertical to avoid damage in a tip over. That is also why the fan is on the inside. 
 

This is why I replaced the stock fan with 4 small puller fans on the  outside of the rads air flow is always one way & no risk of a stone getting caught between fan & rad ! 

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As we go through the post we discover that there is plenty wrong with side mounted radiators after all 🙂

It is Engineering, art of compromise. Front mounted radiator may be less elegant and designers try to hide it but it works well for cooling...

Airplane comparison you have mentioned not always works predictable. For example Spitfire with all its slick looks was aerodynamically lesser to FW-190. Even the second had radial engine with front mounted cooling fan and oil coolers. 

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Didn't someone already test side-mount radiators and find that at certain speeds, forward-flow from fan is negated exactly by outside incoming airflow? Thus resulting in zero flow across radiator and temps keep on increasing even though they were coasting downhill?

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Yep, honda fitted a puller fan rather that spend another couple of Yen for a stone guard. Swapping to the VTR does away with that issue, but makes the stone guard compulsory to avoid rad damage. 

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1 hour ago, DannoXYZ said:

Didn't someone already test side-mount radiators and find that at certain speeds, forward-flow from fan is negated exactly by outside incoming airflow? Thus resulting in zero flow across radiator and temps keep on increasing even though they were coasting downhill?

 

https://grassrootsmotorsports.com/forum/motorcycles-and-bicycles/need-help-identifying-ways-to-improve-my-vfr800s-c/96577/page1/

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2 hours ago, DannoXYZ said:

Didn't someone already test side-mount radiators and find that at certain speeds, forward-flow from fan is negated exactly by outside incoming airflow? Thus resulting in zero flow across radiator and temps keep on increasing even though they were coasting downhill?

I don't know of a scientific test, but empirical experience indicates it's true. That's easily solved with a double throw override switch. I use it to turn the fan off when the engine temp is high enough to have it operating and I'm at a good speed (about 45+ mph).  It works well.  I intended to install a VTR fan blade but did the switch project first - after seeing how well it worked I abandonded the fan swap. 

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