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richy_rich

EWP Controller

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I'm messing around with various ways to better control the electric water pump on my car. 

There's a bit more about it here : https://richyrichracing.com/2018/12/cheap-electric-water-pump-controller-part-1/ but the basic idea is to a) enable a faster warm up - without having to fiddle about with switches and inevitably forget to turn it on at some point and b) keep the engine temperature at a more optimum level (my car runs slightly too cold if anything).

So, I'm after ideas or comments and these seems like a place to get good input   My initial ideas are threefold : 

1/ Just use a themostat and a relay to turn it off and on (with a configurable hysteresis). Pros : Simple -  Cons : If it doesn't work for any reason I'd have to notice and override manually

2/ As 1, use a thermostat/relay for full power, but maintain some kind of minimum operation until target temperature is reached.  Meaning run the pump at a lower voltage (e.g. 4V) until temperature is reached or at a configurable duty-cycle (on 10s off for 30s) etc. e.g. a whacking great resistor (or sufficiently specc'd voltage converter) in the first case, maybe even a flasher relay for the 2nd case.  Pros : Still simple - Cons : Am I over-complicating this?

3/ Ha, overcomplicating? You aint seen nothing yet...  Write custom controller logic for something like an ATMega/Arduino type thing to behave as close to possible to an ideal warm up cycle and keep the temperature rock steady.  Might as well chuck in the fans as well.

I'll probably start with 1 anyway, it'll cost virtually nothing to try.

Is it worth going any further? 

Davies Craig do a very swishy looking thing ( https://www.merlinmotorsport.co.uk/p/davies-craig-lcd-digital-water-pump-fan-controller-8001-dc8001 ) the description states : 

Quote

In simple terms, the LCD digital water pump and fan controller performs three main functions:- Firstly acting in a familiar fashion to a thermostat by limiting coolant flow on initial start up and until the engine is up to temperature. Secondly, the controller varies flow of coolant once up to operating temperature, thus maintaining a steady temperature. And finally, switching on the electric fan should the engine reach above 3° of it's target temperature.


I was thinking something along those lines, but for more like 15-20 quid    n.b. I wouldn't recommend rushing out and buying those cheap thermostats just yet, they're fairly badly designed and badly put together - that said... they do work as advertised and seem fairly agnostic to input voltage (I tested one on the bench at 5-20V and it seemed happy enough but it's early days).

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Mine just has an on/off switch, Richie.     If I'm racing, it's on, all the time.   If I'm touring, I just turn it off once we're going, unless we meet traffic.

John

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Well, yeah.  Mine does too :) but that's no fun.  At the last couple of events I've done the car was running too cold for my liking and I don't want to be fiddling with it on the Kemmel straight..

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The very kindest thing i can say about the Davies Craig controller is that it is pure shite.
They could offer me tens of thousands of pounds and I would still never use any of their products again.

My advice is to use a remote thermostat.

Please read this saga

 

 

Ian.

 

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When it comes to electric water pumps, with the possible exception of Stag and slant 4 cars, I just think.... "why??"  Fixing something that isn't really broke?

If you must do it the hard way though,

3 step control where minimum = warm-up (<70ºC), normal = cruise (70 - 85ºC), max = difficult conditions, ie working hard or sat in traffic (86ºC+).  These all based on engine outlet/radiator inlet temps.

Fan actuation should ideally be based on a different sensor measuring radiator outlet temps as switching it on when you are already barrelling along at 60+ isn't going to help (guess how I know that!).

How you do it electrically is another question.  You should be able to come up with something using Arduino, but that does seem over complex even by EWP standards!

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I'd maybe look at what they do with driving some electric fans, have the pump hooked up to a 6v supply that is always powered when the ignition is on, and then a 12v supply hooked up via a thermostat that cuts in at the desired temperature. Fairly cheap and simple, and as a fall back just have a dash switch that puts 12v via the 6v supply so you can over ride if the need arise.

Alan

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That was my initial thought too Alan, simple and easy to rig up for under a fiver (my arbitrary budget for such projects).

23 minutes ago, Nick Jones said:

When it comes to electric water pumps, with the possible exception of Stag and slant 4 cars, I just think.... "why??"  Fixing something that isn't really broke?

It was the 'thing to do' 15 odd years ago on the small Triumph race cars (although I used the standard pump just fine for a year or two before fitting one....).  One advantage is that it's lighter (assuming you remove the old pump/thermostat housing), the other main thing I've found useful is that you can cool down a very hot car quicker by leaving the pump and fan on when you pull up.  

I wouldn't probably bother on a road car, never had any problems commuting on the M25 in a Spit (well not any related to the water pump/fan).

I doubt I'll go to the bother of making anything with an arduino, the 2 quid digital thermostats will probably be up to the job with a bit of work.  If I did though, something like this https://www.adafruit.com/product/3500 costs less than a tenner, has a 12 bit AD converter input and an add-on waterproof temperature sensor (maybe another fiver?) and is programmable by basically editing a text file on a USB key.  Use one of the outputs to drive a relay (via a transistor or two) and you'd probably have a working prototype in an afternoon.  Massively way over budget though :)

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Hello All

               I have one of the dual thermostats in the bottom of the radiator to control my 2 x 9"fans and relays plus override switch and leds (to know if they are on)

One cuts in at 82deg and down to 78deg the other is 88deg down to 82deg (I think ?)

Only a road car but second fan only came on when sat in motorway traffic in 30degs on a new engine (300 miles) in Bilbao

I like thermostats that are screwed in non of this push a wire or tube under the hose clip(Mr H Robinson springs to mind!)

Roger

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1 hour ago, richy_rich said:

It was the 'thing to do' 15 odd years ago on the small Triumph race cars (although I used the standard pump just fine for a year or two before fitting one....). 

yes it the one piece missing from the spec Martyn gave me for the Red Spit, the electric pump has been replaced with a mechanical, from the wiring it looks like it was just on an on/off switch on the dash though.

Alan

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Yep, I'm just wondering if I can improve on an on/off switch to get better warmups and a more consistent running temp.  Honestly, it's been fine with a switch since I fitted it (apart from the recent running too cold) but I like exploring ideas and I was flicking through a catalogue, saw the expensive controllers and my initial reaction was 'Cheeses, I bet could make that for a fiver'

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8 hours ago, richy_rich said:

Well, yeah.  Mine does too :) but that's no fun.  At the last couple of events I've done the car was running too cold for my liking and I don't want to be fiddling with it on the Kemmel straight..

If it's running cold, even on the Kemmel, then you aren't pushing it hard enough!

JOhn

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Surely the pump should circulate the coolant all the time?
That is what a mechanical pump does...

 

There are some very dubious Davies Craig installations out there for slant four engines,
I say dubious because the controller operates the pump during warmup but no coolant is actually circulated,
in other the pump just spins dry.
This is because the presence of the closed thermostat prevents flow....

Also, if plumbed properly the pump will allow the heater to operate fully.
DC's additional pump "solution" is a pure con.

 

For my Sprint I have bought a Stewart EMP from the USA.

 

Ian. 

 

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Yes, the standard mechanical pump setup on a Spit would pump round the head, heater matrix and inlet manifold regardless of the thermostat being open or closed, opening the thermostat just introduces the rad to the circuit.  I can't remember the slant four setup exactly, but it is surely similar other you'd only ever be able to use the heater on very hot days :)  

Setup on a race car is a bit different, but whatever DC was proposing sounds wrong :/

I do actually want *some* circulation under all conditions, this is kind of my issue with just an on/off switch.  Nick's proposal is pretty much what I'm aiming for actually.

18 hours ago, JohnD said:

then you aren't pushing it hard enough!

Is that a thinly veiled challenge?

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Hello All

                 I would think for a race car 2 steps would be enough!

I would have a sensor by the engine thermostat and wired so the pump is on all the time but running through a voltage regulator while warming up and when sensor says its hot just put full power to the pump bypassing the voltage regulator(loads of cheap ones on Fleabay but may not be rated high enough)

Then a thermostat in the radiator for the fan

You could still have over ride switches for both

But then what do I know I do not race but to me race cars are either ticking over or flat out(in various gears!)so sophistication is not needed?

Roger

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2 hours ago, richy_rich said:

Is that a thinly veiled challenge?

You may say that, I couldn't POSSIBLY comment!

And as for you, Mr.Guzzi!  Not sophisticated?   I'll have you know I'm not just a wild animal, I'm bloody furious!  Bananas at dawn, Sir!

 

Ian,

A mech pump is on all the time, but output  depends on engine revs.     Not so for an electric, unless you fit some sort of speed controller, rather than an on/off switch.

I've been very satisfied with my D-C EWP.    I ground off the vanes on the mech pump, on their advice to remove a mech pump from the circuit,.   It's now just an idler for the 'fan' belt, as it would need one anyway as tensioner.   The system works v.well!      Is you concern only with slant four engines?

John

Edited by JohnD

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The slant 4s and Stags are err..... of mechanically doubtful design.  As well as perhaps not being all that great at pumping (maybe due to cover clearances not set right in some cases) they are moderately prone to seal issues, bearing problems and even chewing the teeth off their shafts or worse, the jackshaft. 

All this makes the motivation for using some other pumping arrangement a little above average.  Electric is one option.  Some use the separate unit belt-driven water pump from the Ford V6.

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4 hours ago, JohnD said:

And as for you, Mr.Guzzi!  Not sophisticated?   I'll have you know I'm not just a wild animal, I'm bloody furious!  Bananas at dawn, Sir!

Hello John

                    I meant the cars the drivers are just plain Balmy!

Roger

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Hi,

 I always thought the EWP was a very good idea.

1.       The EWP has a more efficient pump design. The OEM Triumph impeller looks very inefficient. (of course, the EWP flow was never enough to turn the mech pump if left fitted)

2.       The EWP has more flow at idle speeds. (Now, I have no idea).

3.       The EWP can run with engine off to cool or preheat the engine if suitable oil or water heaters are fitted.

4.       The controller (Old analogue type they no longer sell) Pulses with a variable duty cycle of around 7 volts until around 60c is reached and then it becomes PWM up to the adjusted setpoint.

5.       Faster warm-up time…..

 

I installed my 1st EWP & analogue controller in 2000. Spliced into the bottom hose. OEM pump installed with no drive. Thermostat installed. A fan was controlled by a relay in parallel with pump- fan only came on when pump running above 90c

The heater was kak so bought and installed booster pump fed from the ignition.

Bought a new EWP in 2004 after pump #1 stopped rotating.

 

EWP #2 fitted with water pump blanking plate. A tee into the EWP was provided to give a heater return path. Not too many breakdowns & heater was OK.

2014, EWP#2 starts leaking. Car unusable. Prior to this, the sensor mounted at the same level as temperature sender failed. The pump was wired to constant ignition feed.

 

EWP#3 New and bigger alloy EWP ordered. New shapes and sizes of silicone hose orders. Three port modern 32mm 88c thermostat ordered. Suitable ROC thermistor was ordered to resurrect the analogue EWP controller.

2nd hand water pump purchased and machined with flat thermostat plate and 32mm hose barb in the bottom. Oww. Three port thermostat fitted so coolant flow was modulated thru the radiator. Heater crap again System OK unless the coolant gets a little low-- China syndrome.

14th December 2017. I have the AA report. The drive home from work was interrupted when the unique water pump housing fell to bits.  A place called dick lane. Sat in a damp & wet car with no internet for 5 hours. The two “sisters” in the house that I could see into from my dark vantage spot progressed out of eye-shot. 10;30 got home pissed offski.

Mech pump fitted. 88c thermostat and too much cooling at high RPM. Happy days.

Do not fit an EWP without a restriction from the head. Thermostat or two-pound coin with a hole drilled thru works fine.

Cheers,

Iain.

PS. I do have the 190? Alloy pump somewhere and will sell it.

Edited by spitfire6
PS>

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Hi,

 If you want to control the EWP RPM, I would give it a minimum voltage of around 7 volts and pulse it to adjust RPM. When warming engine up I would not rely on convection.

 I did look at PID control before I realised that I had wasted loads of money and that the crap mech pump is less trouble.

Cheers,

Iain.

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10 hours ago, spitfire6 said:

When warming engine up I would not rely on convection.

That's my thinking too, I would imagine you'd get localised hot spots and coolant boiling away in the head in places whilst other bits stay relatively cold.

The pump will run (and move water around) fine in my engine at ~4V, I think that's a bit on the lower limit so somewhere in the 5-7 range seems about right. I'll have another play around today.

I'm surprised you've had so many fail actually.. Mine's been on the car for over 15 years, but that might not mean much on a race car - it's probably only runs for 10-15 hours a year...

All interesting feedback though and why I asked on here in the first place :)

Pictured is a car (not mine, it's Andy's) and I have basically the same setup, as you can see there's no thermostat housing or pump, it's as simple a circuit as you can get however it works a bit too well.. It also works well for holding screwdrivers as you can hopefully see.

3967911185_f7aaef989b_o.jpg

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23 hours ago, JohnD said:

Is you concern only with slant four engines?

John

No John.

The slant four engines use a standard cooling system, save for the weak link that is the so called "expansion tank",
this curiosity was replaced by a header tank on later TR7s.
An electric pump is desirable on a slant four because it removes the strain on the jackshaft. It also makes the engine
much more free revving, akin to fitting a lighter flywheel.

 

When I contacted Davies Craig about their controller I was told to get lost because they said I was being unreasonable
expecting it to work in the European climate. I wasn't having that, so they then responded by promising (three times no less) to send
a replacement but alas they went back on their word. This is one of they occasions when you have to accept you have been cheated
and then move on.
The Google search on DC I conducted certainly did them no favours, there is forum after forum after forum of problems on various makes.

 

As I said earlier I have bought a Stewart pump. These pump 200 litres/minute and were developed for racing applications
but are of course suitable for road cars. The pump's lifespan is rated at 10,000 hours.

 

 

Thanks,

Ian.

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9 hours ago, JohnD said:

Does the 'fan' belt run as loose as that?

In Andy's car? Yeah, probably :)  It's not like you'd want to waste precious engine power charging your battery, right?  Rules stated "Charging circuit must work", didn't say "work continuously" or "work well"..

No, that was from Nurburgring, 2009. Think his alternator burned out or seized or something and he bought a new one from Luke Wos (I think), this was in the process of fitting it hence the three visible wires at the back.  The braided hose to the expansion tank (or whatever it was) didn't always just rest on the pulley either. 

Pretty sure we left the screwdriver in place though for the race (no really... and it was still there at the end) :D 

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