electric water pumps comments?

Submitted: Friday, Sep 27, 2002 at 00:00
ThreadID: 2060 Views:1660 Replies:6 FollowUps:9
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Considering fitting a Davies Craig electric water pump to replace the belt driven one in the HJ75, turbo 2H motor. She gets hot while idling sometimes and on hot days with AC, towing and pulling a big trailer uphill REAL HOT. Supposed to free up load on motor and therefore allowing more power for driving and be effective at cooling without needing more revs. Also a controller is available to cool the motor and turbo after stopping. What about the smaller backup version that can be added elsewhere in the system? See all this at www.daviescraig.com.au. Makes sense. Anyone running this gear? With Summer on it's way, I would like to get advantage this year.... Cheers Royce
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Reply By: Eric - Friday, Sep 27, 2002 at 00:00

Friday, Sep 27, 2002 at 00:00
Royce.
Dont believe the story on the wab site, you cannot ignore the laws of physics. the alternator has an efficiency of about 25% and the motor on the pump has about 50% efficiency that means that total power used to drive the pump has to increase by a factor of 12. that can only mean more heat in your radiator. A more efficient radiator or fan is what you buy.
Eric.
AnswerID: 7000

Follow Up By: Royce - Friday, Sep 27, 2002 at 00:00

Friday, Sep 27, 2002 at 00:00
Thanks Eric.... do you mean that somehow the alternator has to work harder and therefore more heat is generated? Or transfer of energy is less efficient when using electric vs belt drive? How does that work? Or do you mean that the water flow is likely to actually be less via electric pump rather than direct drive from engine? Hmm I'm still puzzled. PS I have upgraded to a larger radiator and the thermo fan is fine. Cheers Royce
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Follow Up By: Colin - Monday, Sep 30, 2002 at 00:00

Monday, Sep 30, 2002 at 00:00
Eric, sorry but you dont know what you are talking about, the alt. is working all the time and the regulator cuts in and out as the battery needs charging or not, so the electric pump wil not put any extra load on the motor as it gets its power from the battery. Dont know much about the elec motor but have been looking at it also, and have heard good reports, have also heard car manufacturers are also interested in the system. Regards Colin
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Follow Up By: Eric - Monday, Sep 30, 2002 at 00:00

Monday, Sep 30, 2002 at 00:00
Colin.
Thanks for your kind words.
You are right the alternator is turning all the time and the regulator does control the output from the alternator, but if you put more loads on the alternator the regulator turns on the alternator harder and more often.
If what you say is true we would be getting something for nothing and we both know that only politicions get that.
keep thinking ,Eric
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Follow Up By: Colin - Tuesday, Oct 01, 2002 at 00:00

Tuesday, Oct 01, 2002 at 00:00
Eric, the alt. is working and makeing 14 plus volts all the time all the reg. does is stop power going to the battery when charged . You can not load the alt up any more than it is doing. Think about when you have the lights on high beam with spotties fridge in the back sterio on and a trailer with all its lights on do you see the temp guage rise, no as the alt is still working the same as if no current is being drawn, if your alt is loading up to the point of riseing the eng temp you have a very serious elec. problem. Col
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Follow Up By: Stephenf - Monday, Oct 07, 2002 at 00:00

Monday, Oct 07, 2002 at 00:00
Colin is right. You don't get something for nothing. If electrical energy is used it must be generated somewhere. As you increase the electrical load the alternator generates more current to keep the battery topped up. This is felt as increased drag by the alternator on the engine, which must use more fuel to overcome the drag. If you don't believe me, turn the headlights on and listen to the drop in speed of an idling engine (more noticeable on a small engine).
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Follow Up By: Stephenf - Monday, Oct 07, 2002 at 00:00

Monday, Oct 07, 2002 at 00:00
Ummm...I meant Eric is right.
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Reply By: coops - Saturday, Sep 28, 2002 at 00:00

Saturday, Sep 28, 2002 at 00:00
Royce
Have you tried a new & different setting thermostat. I live in the Pilbara and fitted an 82 degree model as opposed to 92 degree model (or vice versa - best you check) and find it runs marginally cooler. Not that I had a problem initially, it's just something that was recommended and I figured would be beneficial when under load. Temp gauge doesn't budge when in sand or even on the open road on a red hot day at high speed.
I looked at EWP and was impressed enough to consider it (at next Lotto win) but have taken Eric's comments on board and will look further if closer to an actual purchase. Given I have no problems currently I don't see the need to go there now though.
AnswerID: 7012

Follow Up By: Royce - Saturday, Sep 28, 2002 at 00:00

Saturday, Sep 28, 2002 at 00:00
I've got a tray back 75 with no problems, but the big SupaTrupa runs hotter. Strangely after turbo charging, it improved. A larger radiator and the problem is greatly improved. Still runs hotter than I like and races to the top under heavy load. It really seem to relate to revs. If I drop back a gear and run at higher revs it improves, and when I sit idling on hot days it climbs. The booster/ backup pump they sell might be the option I'll go for. Still thinking. I'll look into thermostat options. Thanks for the info. Cheers Royce
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Reply By: Eric - Saturday, Sep 28, 2002 at 00:00

Saturday, Sep 28, 2002 at 00:00
Royce.
The energy to drive the electic pump must come from the alternator and the energy to drive the alternator must come from you diesel motor so it is best to drive the pump directly from the motor and save wasting all that extra energy that is going to make your radiator work even harder.
The 2h motor, if is run without corosion ihibitor will grow nasty big scales on the blades of the water pump if you have access to a press you could change the 4 blade rotor for a 6 blade from a later model. I gather you are running an elecric fan, the same efficiency problem. A directly driven thermo clutch fan is much better.
Eric.
AnswerID: 7027

Reply By: Darryn - Monday, Sep 30, 2002 at 00:00

Monday, Sep 30, 2002 at 00:00
Royce have you tried or thought of an external oil cooler? I have seen several 2H Tojo's overheat with aftermarket turbos and most were cured with an oil cooler. Regd's Darryn
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Follow Up By: Royce - Monday, Sep 30, 2002 at 00:00

Monday, Sep 30, 2002 at 00:00
thanks Darryn.... I am considering that. Cheers
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Reply By: Member - John - Monday, Oct 07, 2002 at 00:00

Monday, Oct 07, 2002 at 00:00
Royce, Be very careful. I fitted a Davies Craig EWP to a Nissan Patrol GQ 2.8 TD and it didn't keep it cool, even when running EWP flat out, removed pump and got a refund. A couple of weeks later, when fully loaded for two month trip to Kimberely, an hour into trip and head gasket blew. Expensive, $2000.00 to fix. As I said, be careful in your choice. John
AnswerID: 7225

Follow Up By: Ken D - Tuesday, Oct 08, 2002 at 00:00

Tuesday, Oct 08, 2002 at 00:00
All
Heat and load are directly related- You say the engine overheats when it's idling. diesels don't generate anywhere near the heat of a petrol engine when not on load.- This means you have a fault or faults.- Fan is only of use when the car is at standstill or travelling very slow, could still be the fan as well, but the problem would go away when you are moving- As suggested earlier, could be thermostat, could be impeller on water pump is buggered, or blocked radiator- Once the fault is cleared up the other issue is under heavy load- Your turbo engine is going to make more power so you are going to have to get rid of more heat than the factory setup.- Toyota cooling systems are marginal even when new. I have used HJ and HZJ landcruisers for work. Pull a big trailer and drive hard, AC on, and they will overheat, Newer tojos switch of AC when the heat comes up.- Was the cooling system upgraded when the turbo was fitted?-Only reasonable way is to increase radiator size or air flow.-Can't do much about airflow except make sure the area in front and behind the radiator is clear-
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Reply By: royce - Wednesday, Oct 09, 2002 at 00:00

Wednesday, Oct 09, 2002 at 00:00
This thread is a bit old now.... but someone might be searching and have found it! I have just completed a 2" lift on the old girl. Guess what I found. As I went through everything to make sure all was well, I discovered the bottom belt was very loose. Tighened it and things have improved. I had a four core radiator fitted after turbo-ing and this did make a big difference. For really heave loads I have worked out a plan: I intend fitting an old Subaru radiator under the belly of the SupaTrupa. It has its own electric fans. I'll then fit a Craig Davies backup pump to move coolant back through this second radiator when under load. I'll wire it up so that I can operate from the cab or automatically. It's all fun!
AnswerID: 7280

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