Electric Water pump - Davies Craig EWP

[Nakkas]

Its not using extra fuel. Quite the opposite. Sitting on 80 kph, it's using 9-10 l/100 km. The EWP does not run all the time



The pump only runs constantly when the temp goes above the set temp, which is 95 deg.
The controller takes the place of the thermostat.

[carvesdodo]

Originally Posted by MudMonkey30

2 things I can think of that cause the extra fuel!
1: if it revs quicker it might be using a litte extra that way.
2: if it keeps it to cool then it might (even if it's only for a few seconds) it might possibly be in warm up mode.


Getting back to the thermostat and where you have possitioned the temp guage for the new pump!
As mentioned before, it might be wise to take the temperature closer to the heads for obviouse reasons.
I believe the extra flow provided from removing the thermostat is good and bad, cools it down quicker, this can also do damage as motors are designed to run at a constant temp not a fluctuating temp causing warping and other head aches,,,
I would try and find a lower temp thermostat so that it still has the proper warm up mode and possibly a more constant flow. Maybe even drill a larger hole in the thermostat as per gojeep's site..
I am not in anyway saying your mod is a bad one by any means,
but the amount of research I have done lately due to Cherokee overheating problems, I believe more can be done to help the motor and the rest of the system stay at a closer constant temp.
Electric water pumps are a good thing.
There only bad side is, when they stop they stop!!
My 2c

I read that he had a fuel improvement too. Altho if the belt is still routed around the pump pulley, one wouldnt be expecting a lot of difference ... time will tell ... so keep the info coming Nakkas.

Im a bit worried about the removed thermostat also ... Its part of the reason I originally asked about monitored temps at both ends of the engine.


Aiming for that "constant" temp you mentioned, will certainly resolve a lot issues. Butchering perfectly good thermostats mightnt tho.

Warm up mode ??? ... you mean when the obd2 system changes from open to closed loop at 20'C ... and the earlier system probably does the same ????


A mechanical pump just shunts coolant through the system ... Typically - as the revs increase it will pump faster meeting the needs of the engine getting hotter.

If the pump is matched to the motor (as a factory fitted one should be ) ... - the coolant flow rate should be such that it is neither too fast, nor too slow for effective heat transfer at all rev ranges.

The EWP which is varying pump speeds all the time, based on the top hose temp rather than the engine temp, or rev range ... may not allow for proper heat transfer.

Just applying the ol ...

too fast through the radiator & coolant doesnt get cooled properly,
too fast through the engine & it doesnt absorb enough heat,
too slow through the engine & it maintains high temps ....

... info that is out there to read about.

Just wondering if the electric control of the pump results in something similiar to a faulty fanclutch e.g. not enough happening at the right time ... even though the engine bay temp says it should be working.

Ahhhh ... more info halfway through typing .... thanks Nakkas.

Originally Posted by Nakkas

Its not using extra fuel. Quite the opposite. Sitting on 80 kph, it's using 9-10 l/100 km. The EWP does not run all the time

The pump only runs constantly when the temp goes above the set temp, which is 95 deg.
The controller takes the place of the thermostat.

Something to consider ...

95'C temp at the top hose sensor with no coolant movement .... whats the water gallery coolant temps ???

Have you got a ... pump activated ... light in the cab ... to compare against the factory thermostat housing sensor temps ???

I might be getting too ******** about the whole thing .... but static coolant will boil real quick

[Deezelweazel]

I'm a bit concerned about a non moving pump.
As I know the heads of the I6 are sensitive to heat. A non running pump could lead quickly to hot spots.

On the other hand a non existing thermostat can cause to quick coolant circulation.
When this happens, the coolant doesn't remain in the engine long enough to efficiently heat and carry it away to the radiator.

Power gain can be in the range of 5-15hp- that is what the normal water pump consumes depending on engine speed.
Thats your new gained power you feel during acceleration.

According to VW engineers a full saving of 2% is possible with an electric waterpump.
2% savings are debatable on an intial cost side of 399$.
It's the same 2% saving with switching to Synthetic oils.

The savings you gained( 2litre) are explainable due to efficient crusing speed.

Whats the electric power consumption of the pump?

[MudMonkey30]

Yeah my mistake, I'm sick and all drugged up!!
Plus I use my iPhone more then my computer now, just more convenient even with the tiny writing!!
Well if better fuel consumption It is then all the happier!
I am now wondering about the thermostat myself, now after reading that the pump is idle untill needed your start up should be as normal,
still more to consider in the long run anyways!
Mudminkey out... Cough cough, I'm going back to bed!!!!

[Nakkas]

Just for interest, I did a 150 km round trip yesterday. Outside temp was 39 deg. 75 kms one way at 100 kph averaged 9.5 lt/100 without AC and 10.3 lt/100 with AC, on the way back. No wind. Flat road. The Temp guage sat on one notch below the 100 mark. When I got into town, it crept to just under the 100 mark.

[rusty577]

Originally Posted by Nakkas

Just for interest, I did a 150 km round trip yesterday. Outside temp was 39 deg. 75 kms one way at 100 kph averaged 9.5 lt/100 without AC and 10.3 lt/100 with AC, on the way back. No wind. Flat road. The Temp guage sat on one notch below the 100 mark. When I got into town, it crept to just under the 100 mark.

nice lt/100km Mine averages around 15lt/100km around town driving like a granny

[Nakkas]

The EWP has been working well in the 45 degree temps we had during the Hot months. Now that the temps have plumeted to the mid 20's, things are not normal. It is difficult to get the engine temps to maintain the 95 deg that is set on the controller. When I am at a standstill, it will sit on 95 deg. When I start moving the coolant temp drops. This means the radiator is working too well, or the 115 Lt/Min pump may be too large, flowing too much water. There is a 80 Lt/min option. I spoke to John at Davies, Craig and he suggested putting the Thermostat back in and drill a 6mm hole on the Thermostat. This will restrict the flow slightly at colder temps until the temp reaches 95 deg. I will try this on the weekend and post the result. At least the engine has never risen above the 105 deg mark, which it used to before. With the engine running cooler, the mixture will be richer and I get a bit more performance from her/him. (haven't worked out a gender yet)