Davies Craig EWP
Discussion
I can't comment on the Davies Craig pump, but someone recomended these to me as being better.
http://www.stewartcomponents.net/Merchant2/merchan...
I don't have experience of them, as it's too early in my build, but maybe it's another option to consider.
http://www.stewartcomponents.net/Merchant2/merchan...
I don't have experience of them, as it's too early in my build, but maybe it's another option to consider.
Do not use the controller. The theory is that you use the pump as a thermostat, flow the water slowly through the engine until it heats up, and then flow it faster.
Problem with this is that if the water is not flowing through the engine at any speed, it could be boiling at the inlet or middle and so long as its relatively cold passing the sensor, then the pump keeps going slow.
What you want to do is run the pump flat out but use a conventional thermostat with a bypass circuit to control the heat. i.e. Pump will pump bypass circuit in a loop until it heats up enough to open 'stat, when the pump then pumps main circuit too.
You could use the controller (I believe) to run the pump on after the engine has shut off. This is good, but you could do this with a bit of electronics and relays, especially if you have an ECU (or digital dash) you can output a voltage from when the temperature gets over a set limit to open a latching relay with a timer to shut (Timer activated by normally open relay held closed by ignition).
Willie
(Sorry its lunch and I needed something to rabbit on about)
Problem with this is that if the water is not flowing through the engine at any speed, it could be boiling at the inlet or middle and so long as its relatively cold passing the sensor, then the pump keeps going slow.
What you want to do is run the pump flat out but use a conventional thermostat with a bypass circuit to control the heat. i.e. Pump will pump bypass circuit in a loop until it heats up enough to open 'stat, when the pump then pumps main circuit too.
You could use the controller (I believe) to run the pump on after the engine has shut off. This is good, but you could do this with a bit of electronics and relays, especially if you have an ECU (or digital dash) you can output a voltage from when the temperature gets over a set limit to open a latching relay with a timer to shut (Timer activated by normally open relay held closed by ignition).
Willie
(Sorry its lunch and I needed something to rabbit on about)
Thanks for the info. Never thought of the ECU until mentioned.
Using the OMEX 600 series you can get an output for the radiator fan. This can be set ON at the decided temp and OFF at a lower temp. So i suppose if you could use this in the supply circuit for the EWP then it would come ON when required then set much lower, as in a desirable temp to stop pumping when engine not running but ignition on, to go OFF.
If the engine became hot whilst the EWP's running at idle (summer-european circuits), then a manualy operated fan could be fitted, or by using the second temp output of the ECU which has to be configured to an aux output. This can be set at a say 10 deg higher than op temp and to go OFF when it reaches the EWP ON temp.
I have confused myself now so any discrepencies you can see please advise!!
Using the OMEX 600 series you can get an output for the radiator fan. This can be set ON at the decided temp and OFF at a lower temp. So i suppose if you could use this in the supply circuit for the EWP then it would come ON when required then set much lower, as in a desirable temp to stop pumping when engine not running but ignition on, to go OFF.
If the engine became hot whilst the EWP's running at idle (summer-european circuits), then a manualy operated fan could be fitted, or by using the second temp output of the ECU which has to be configured to an aux output. This can be set at a say 10 deg higher than op temp and to go OFF when it reaches the EWP ON temp.
I have confused myself now so any discrepencies you can see please advise!!
That looks sensible enough thinking, but you're still going to need some relay type trickery.
If you use ONLY the ECU output to power the pump, and you need the pump to run as soon as ignition is on, your ON temp will likely be something like -20degC (To make sure it comes on - remember, you're using the thermostat for water temperature control). Problem with that is, no matter what you set your OFF temp to, it's never going to switch off...unless it's below -20deg, until you IGN OFF.
If the output is the only power to the pump, you cannot set your ON temp to, say, 40degC because with no water circulating, by the time 40degC has reached your sensor and the pump turns on...the water sitting in the head will be boiling away.
You could do as you have described, but with an additional power supply to the pump, separate to the IGN. You get in the car, switch pump on, start engine and away you go. When you stop, you switch IGN OFF, engine kills, IGN ON then your ECU output will power the pump if it is between the ON/OFF temps and so you can turn your manual pump switch OFF and leave the ECU to turn the pump off when it gets below the lower temp.
You'd need a decently high value for the ON, say 80 or 90degC, as you don't want it draining the battery unnecessarily. That means you have to remember to flick on the manual pump switch every time you get in, otherwise you're going to toast the engine.
I still think the best way is a couple of latching relays and a simple Maplin timer circuit. The pump gets power on IGN ON and stops on IGN OFF. An entirely separate circuit does your run on with a timer switching it off. You could likely use a thermo-switch if you could find a suitable one.
I had thought of a normally closed relay with a feed from the battery being held open via IGN circuit, so no power goes through the "main" loop. The output from this relay's main loop goes into a latching normally open relay which is latched closed by a feed from the ECU when it's above 80degC. This means when the car has been above 80degC and you turn it off, power can get through the two relays and activates the simple timer circuit providing power to your pump (and fan) for however long you work out it takes to get the temp to a nice level.
There is a bit I'm missing here, which is the resetting of the latching relay, can't remember how I had worked it out, but a carbon crankset (bikes) is ending on eBay so I'd better end up. Draw it out if you're keen on the idea.
Willie
If you use ONLY the ECU output to power the pump, and you need the pump to run as soon as ignition is on, your ON temp will likely be something like -20degC (To make sure it comes on - remember, you're using the thermostat for water temperature control). Problem with that is, no matter what you set your OFF temp to, it's never going to switch off...unless it's below -20deg, until you IGN OFF.
If the output is the only power to the pump, you cannot set your ON temp to, say, 40degC because with no water circulating, by the time 40degC has reached your sensor and the pump turns on...the water sitting in the head will be boiling away.
You could do as you have described, but with an additional power supply to the pump, separate to the IGN. You get in the car, switch pump on, start engine and away you go. When you stop, you switch IGN OFF, engine kills, IGN ON then your ECU output will power the pump if it is between the ON/OFF temps and so you can turn your manual pump switch OFF and leave the ECU to turn the pump off when it gets below the lower temp.
You'd need a decently high value for the ON, say 80 or 90degC, as you don't want it draining the battery unnecessarily. That means you have to remember to flick on the manual pump switch every time you get in, otherwise you're going to toast the engine.
I still think the best way is a couple of latching relays and a simple Maplin timer circuit. The pump gets power on IGN ON and stops on IGN OFF. An entirely separate circuit does your run on with a timer switching it off. You could likely use a thermo-switch if you could find a suitable one.
I had thought of a normally closed relay with a feed from the battery being held open via IGN circuit, so no power goes through the "main" loop. The output from this relay's main loop goes into a latching normally open relay which is latched closed by a feed from the ECU when it's above 80degC. This means when the car has been above 80degC and you turn it off, power can get through the two relays and activates the simple timer circuit providing power to your pump (and fan) for however long you work out it takes to get the temp to a nice level.
There is a bit I'm missing here, which is the resetting of the latching relay, can't remember how I had worked it out, but a carbon crankset (bikes) is ending on eBay so I'd better end up. Draw it out if you're keen on the idea.
Willie
Edited by WillieSkelly on Wednesday 19th January 22:21
I not too sure on the quality of the Davies Craig pumps. After I bought one I recognised the motor from something else thats unreliable I sold it straight on again. I fitted a Stewart pump on my busa and it was brilliantly perfect! No funky wiring just the ignition firing a relay and the pump runs all the time but there was a stat bypass fitted.
http://www.locostbuilders.co.uk/photos.php
Jason
http://www.locostbuilders.co.uk/photos.php
Jason
Edited by Purespeed on Wednesday 19th January 23:32
WillieSkelly said:
That looks sensible enough thinking, but you're still going to need some relay type trickery.
If you use ONLY the ECU output to power the pump, and you need the pump to run as soon as ignition is on, your ON temp will likely be something like -20degC (To make sure it comes on - remember, you're using the thermostat for water temperature control). Problem with that is, no matter what you set your OFF temp to, it's never going to switch off...unless it's below -20deg, until you IGN OFF.
If the output is the only power to the pump, you cannot set your ON temp to, say, 40degC because with no water circulating, by the time 40degC has reached your sensor and the pump turns on...the water sitting in the head will be boiling away.
You could do as you have described, but with an additional power supply to the pump, separate to the IGN. You get in the car, switch pump on, start engine and away you go. When you stop, you switch IGN OFF, engine kills, IGN ON then your ECU output will power the pump if it is between the ON/OFF temps and so you can turn your manual pump switch OFF and leave the ECU to turn the pump off when it gets below the lower temp.
You'd need a decently high value for the ON, say 80 or 90degC, as you don't want it draining the battery unnecessarily. That means you have to remember to flick on the manual pump switch every time you get in, otherwise you're going to toast the engine.
I still think the best way is a couple of latching relays and a simple Maplin timer circuit. The pump gets power on IGN ON and stops on IGN OFF. An entirely separate circuit does your run on with a timer switching it off. You could likely use a thermo-switch if you could find a suitable one.
I had thought of a normally closed relay with a feed from the battery being held open via IGN circuit, so no power goes through the "main" loop. The output from this relay's main loop goes into a latching normally open relay which is latched closed by a feed from the ECU when it's above 80degC. This means when the car has been above 80degC and you turn it off, power can get through the two relays and activates the simple timer circuit providing power to your pump (and fan) for however long you work out it takes to get the temp to a nice level.
There is a bit I'm missing here, which is the resetting of the latching relay, can't remember how I had worked it out, but a carbon crankset (bikes) is ending on eBay so I'd better end up. Draw it out if you're keen on the idea.
Willie
Nice circuit. Ive been looking at it and drawing it out over the past day or so. I think before i fit the pump, ill need some figures from the normal mech pump to work to:If you use ONLY the ECU output to power the pump, and you need the pump to run as soon as ignition is on, your ON temp will likely be something like -20degC (To make sure it comes on - remember, you're using the thermostat for water temperature control). Problem with that is, no matter what you set your OFF temp to, it's never going to switch off...unless it's below -20deg, until you IGN OFF.
If the output is the only power to the pump, you cannot set your ON temp to, say, 40degC because with no water circulating, by the time 40degC has reached your sensor and the pump turns on...the water sitting in the head will be boiling away.
You could do as you have described, but with an additional power supply to the pump, separate to the IGN. You get in the car, switch pump on, start engine and away you go. When you stop, you switch IGN OFF, engine kills, IGN ON then your ECU output will power the pump if it is between the ON/OFF temps and so you can turn your manual pump switch OFF and leave the ECU to turn the pump off when it gets below the lower temp.
You'd need a decently high value for the ON, say 80 or 90degC, as you don't want it draining the battery unnecessarily. That means you have to remember to flick on the manual pump switch every time you get in, otherwise you're going to toast the engine.
I still think the best way is a couple of latching relays and a simple Maplin timer circuit. The pump gets power on IGN ON and stops on IGN OFF. An entirely separate circuit does your run on with a timer switching it off. You could likely use a thermo-switch if you could find a suitable one.
I had thought of a normally closed relay with a feed from the battery being held open via IGN circuit, so no power goes through the "main" loop. The output from this relay's main loop goes into a latching normally open relay which is latched closed by a feed from the ECU when it's above 80degC. This means when the car has been above 80degC and you turn it off, power can get through the two relays and activates the simple timer circuit providing power to your pump (and fan) for however long you work out it takes to get the temp to a nice level.
There is a bit I'm missing here, which is the resetting of the latching relay, can't remember how I had worked it out, but a carbon crankset (bikes) is ending on eBay so I'd better end up. Draw it out if you're keen on the idea.
Willie
Edited by WillieSkelly on Wednesday 19th January 22:21
Start the engine and let it get to operating temp, then measure temp at various points. Im using the Raceline water rail which has a few places were extra senors can go. With the most suitable one's (closest to the block near the coil pack maybe),temp taken this figure can be used for the ECU ON for circuit, maybe 5 deg below for safety. Then set a lower temp as mentioned so it not switching off and on all the time.
The fan can be from the AUX port and set for higher temps than the pump. Although i think this will only come into play at idle as the coolings pretty good at the mo, radiator-air flow wise. With the pump giving it 80 lpm over whatever it is at idle i would have thought it be better.
But then it makes you think, why not all manual. Turn engine on an wait until 80-90 deg, turn pump ON. If it gets hotter turn the fan ON. Go round to the grid after green flag lap turn fan off, jam on around the track follwing lights out.
The initial bit would just be incrporated in the engine warming up process, which is keeping it around 3000 until it reaches 65 deg then have it idle at 1500, as per formula atlantic cosworth start up procedure. You have two switches for IGN and fuel pump so one more with an ON light wont make any difference. You keep an eye on temp anyway during holding area dn green flag laps, and the engine has proven to keep cool when racing with just the mech pump.
I noticed SBD uses the EWP a lot so might give him a tinkle, if not for the nice blanking plates!!.
http://www.sbdev.co.uk/Duratec/Cooling_system_comp...
Sam,
I think if you're not running the pump constantly when the engine is running...you're going to cook your engine. You're relying on heat soaking through stationary coolant to tell a sensor a good distance away what the temperature is...and whatever it says you can be certain it's about another 20degC around the combustion chamber.
Let a thermostat look after temperature control. The only real advantages of an EWP are remote mounting and the run on ability.
Willie
I think if you're not running the pump constantly when the engine is running...you're going to cook your engine. You're relying on heat soaking through stationary coolant to tell a sensor a good distance away what the temperature is...and whatever it says you can be certain it's about another 20degC around the combustion chamber.
Let a thermostat look after temperature control. The only real advantages of an EWP are remote mounting and the run on ability.
Willie
WillieSkelly said:
Sam,
I think if you're not running the pump constantly when the engine is running...you're going to cook your engine. You're relying on heat soaking through stationary coolant to tell a sensor a good distance away what the temperature is...and whatever it says you can be certain it's about another 20degC around the combustion chamber.
Let a thermostat look after temperature control. The only real advantages of an EWP are remote mounting and the run on ability.
Willie
Yes i think your right. Ive been doodling over the past couple of days with your info. Ill try and scan a copy. The main un-timed circuit to the pump, that gets its relay signal for ON from the 'high' temp figure, could have a parrallel circuit wth a resistor or voltage reg in, so when the IGN is ON it gets a % of power to push a bit round the engine. When the HIGH temp from the ECU triggers the relay full IGN power goes to the pump and takes the path of least resistance. Then again if you reckon the stats the best way, it would be simple as its already installed......you got to remember im on a rig here so plenty of time to think of the complicated and totaly unpracticalI think if you're not running the pump constantly when the engine is running...you're going to cook your engine. You're relying on heat soaking through stationary coolant to tell a sensor a good distance away what the temperature is...and whatever it says you can be certain it's about another 20degC around the combustion chamber.
Let a thermostat look after temperature control. The only real advantages of an EWP are remote mounting and the run on ability.
Willie
I will have to see how its wired cant quite remember, but the ECU will have to get power seperatly from the the IGN otherwise when the IGNs off it wont give a temp to the timer circuit.
Itching to get home for a play!!
pikeyboy said:
To be honest I'm not sure why people bother with EWP's they offer little if any gain over a mechanical pump and its just another thing to not work or be problematic.
Well, in my scenario it enabled me to run one radiator instead of 2.It never failed in my use. also the standard pump was known to cause cavitation at higher rpms and reduce efficiency. I guess those are the reasons I "bothered"normalbloke said:
pikeyboy said:
To be honest I'm not sure why people bother with EWP's they offer little if any gain over a mechanical pump and its just another thing to not work or be problematic.
Well, in my scenario it enabled me to run one radiator instead of 2.It never failed in my use. also the standard pump was known to cause cavitation at higher rpms and reduce efficiency. I guess those are the reasons I "bothered"Not sure how using a EWP allows you to use a single rad unless said caviation issues where causing overheating meaning you needed two in order to keep the temps down.
Knowing someone who's done back to back rolling road testing of an EWP v std mechaincal pump any perfomance increase obtained by reduced drag of an EWP is almost unoticeable, hence why I cant really see why they are worth bothering with. Same goes for alternator removal.
I have had a Davies Craig EWP on my 250bhp K series unit and it has run without any issues for a couple of years for me and presumably a couple of years for the previous owner. One benefit is that on Track days, you can leave the pump running at the end of a session to avoid any of the boiling issues that can happen with high performance K series heads. A big thumbs up from me.
This thread comes up on a google search for Davies Craig EWPs/controllers and will do for evermore...so just to put (intelligent) minds at rest with advice borne of real experience of DC pumps and controllers over more than 10 years - ...
The use of an electronic controller:
To date there are now three iterations of DC controllers -
1) the original analogue;
2) the digital upgrade v1;
3) digital v2
The worst of these is 1) the original analogue controller -but it is still OK if you apply commonsense. At startup it runs VERY slowly then pulses the coolant which means it's relatively slow to react to abrupt temp increases at this point -again that's OK but it makes the positioning of the sensor ultra CRITICAL - it must be inside the head within a stream of the hottest coolant flow - preferably at the furthest point from the cooler radiator input flow - this will vary from engine to engine - so the user needs to apply a bit of intelligence re: these potential issues. you can also add a resistor to the temp sensor wire to make the controller react more vigorously to 'cooler' temps - it's an official DC mod and works OK.
The 2) digital controller (v1) algorithm is better in that once you're into the mid-point of the warm-up phase the voltage increase is continuous and not pulsed like the original analogue -this means the sensor will see temp increased in a more timely way. The crap bit about the digital v1 is the 'jumps' in the fixed temperature presets -better to have continuous control of temp settings -which the 3) digital controller v2 addresses somewhat.
Any catastrophic engine failure when using DC temp controllers will be because the user is a bit thick and can't work with 'basic physics' to apply the fixed characteristics of the given controller to their application. If you are stupid enough to fit the sensor in a hose miles away from the heat source then - tough s
t.
On the reliability front - I'm still using both the very original DC EWP80 pump and the upgrade with ceramic bearings - no sign of failure in 10 years for either as the ONLY pump used in a high revving (10krpm) competition Clan engine and a bigger Lotus 912 road car - both under analogue temp control (the worst of the three controllers).
On the question of increased engine performance - yes the swap to an EWP does mean better engine performance but you won't see it on a dyno -same as you won't see the changes a lightened flywheel will bring - because dynos measure power at steady constant revs and does not account for the increased acceleration to the next measurement point (doh!). Believe me, on the road both the lightened flywheel and the change to an EWP is a worthwhile performance mod in the real world.
The use of an electronic controller:
To date there are now three iterations of DC controllers -
1) the original analogue;
2) the digital upgrade v1;
3) digital v2
The worst of these is 1) the original analogue controller -but it is still OK if you apply commonsense. At startup it runs VERY slowly then pulses the coolant which means it's relatively slow to react to abrupt temp increases at this point -again that's OK but it makes the positioning of the sensor ultra CRITICAL - it must be inside the head within a stream of the hottest coolant flow - preferably at the furthest point from the cooler radiator input flow - this will vary from engine to engine - so the user needs to apply a bit of intelligence re: these potential issues. you can also add a resistor to the temp sensor wire to make the controller react more vigorously to 'cooler' temps - it's an official DC mod and works OK.
The 2) digital controller (v1) algorithm is better in that once you're into the mid-point of the warm-up phase the voltage increase is continuous and not pulsed like the original analogue -this means the sensor will see temp increased in a more timely way. The crap bit about the digital v1 is the 'jumps' in the fixed temperature presets -better to have continuous control of temp settings -which the 3) digital controller v2 addresses somewhat.
Any catastrophic engine failure when using DC temp controllers will be because the user is a bit thick and can't work with 'basic physics' to apply the fixed characteristics of the given controller to their application. If you are stupid enough to fit the sensor in a hose miles away from the heat source then - tough s
t.On the reliability front - I'm still using both the very original DC EWP80 pump and the upgrade with ceramic bearings - no sign of failure in 10 years for either as the ONLY pump used in a high revving (10krpm) competition Clan engine and a bigger Lotus 912 road car - both under analogue temp control (the worst of the three controllers).
On the question of increased engine performance - yes the swap to an EWP does mean better engine performance but you won't see it on a dyno -same as you won't see the changes a lightened flywheel will bring - because dynos measure power at steady constant revs and does not account for the increased acceleration to the next measurement point (doh!). Believe me, on the road both the lightened flywheel and the change to an EWP is a worthwhile performance mod in the real world.
Edited by Lotus-e-Clan on Friday 2nd September 20:46
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