Landracing Forum
Tech Information => Technical Discussion => Topic started by: SteveM on November 26, 2014, 04:42:22 PM
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I'm investigating the possibility of running an electric water pump for the "next" engine which will go into my Rampage. I'm planning a Mercedes diesel, and would like to ditch the accessory drive belt if possible.
That engine will make a lot more power than my little VW (at least twice as much).
For those of you using in-line type electric water pumps, what are you using, and how well is it working for you?
Steve.
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Could you give us an estimate on the HP level and assuming your going to use a turbo how much boost are you going to have.
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400 HP, turbo diesel, maybe 60 lbs of boost.
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call Francis on Monday at Ron's Fuel injection in Tucson AZ I think they have a pump for Sprint cars
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I think a belt driven water pump would be a better option in this application. With 60lbs of boost you will want the pump pressure and flow a belt driven pump will give you. Most racing electric water pump create very little pump pressure. Pump pressure will help to scrub heat out of the head(s) better. Plus a belt driven pump will flow a greater amount of water above 2500 rpm pump speed.
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Most racing electric water pump create very little pump pressure. Pump pressure will help to scrub heat out of the head(s) better.
x2
If your cylinder heads run hot enough to induce "steam pockets" in some areas, then the additional fluid pressure of a belt driven pump will probably be needed. That has been my experience.
:cheers:
F/B
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......If your cylinder heads run hot enough to induce "steam pockets" in some areas, then the additional fluid pressure of a belt driven pump will probably be needed. ....
.............or if the rules permit in your class think seriously about a rad-in-a-box.
(http://purplesagetradingpost.com/sumner/Hooley%202013/rad-in-box-58.jpg)
Now you can have pressure and flow on the radiator/engine side. You still need a pump from your main tank to the rad-in-a-box but it isn't now as critical and some have the radiator in the main tank. Separate tanks do have advantages though.
What we did and I like it over what we had a lot....
http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20hooley-construction-2013-13.html
Sumner
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If hot spots are a problem, wouldn't a belt driven pump give added pressure in addition to what the system is pressure relieved at?
Ron
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We run a 600hp twin turbo Duramax in a street rod with a Davies-Craig electric pump beside the engine. We put over 4000 miles on it this year when we ran Drag Week & we drove it there & back. For a race only application get the one without the controller.
Sid.
https://www.google.com/#q=davies+craig+electric+water+pump&tbm=shop
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I have used the 1 1/4" version of this one with no problems. http://www.stewartcomponents.com/index.php?route=product/product&path=63&product_id=70
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Since I went to a mechanical pump I have not hurt any more heads---you need PRESSURE to suppress the formation of the steam bubbles several have stated this in different ways!
love my Stewart BBC high volume pump with a restrictors or thermostat to keep the pressure UP!
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I've run electric pumps on my GMC's since I started in 1975. Seems like I've tried them all. The best one in the garage was a Stewart Coomponents but it didn't like any heat near the controls and had a funny way of starting. The Mezere ended being the best. i believe it stated 50/60 gpm free flow and emptied my water tank in less than 15 seconds shooting out a -16 hose 20'. With restrictors in the return lines there is pressure in the engine enough to cool without problems... Good luck.JD
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I second Davies Craig pumps. Work great. Only problem we had is once the coolant boils the pump cavatates which would probably happen to any pump. Why don't we run a pressurized cooling system you may ask? Because when you run an 80 year old engine that's full of cracks and crank repair jobs, you don't want water going places it shouldn't (like into the cylinders).
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80-year-old Toyota?
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Stan
Nathan meant the Royal "We" as in his family's car, not "My" car, which is a GMC, says so on the cylinder head :evil:
I'm with Sparky, run a mechanical pump, and a sophisticated cooling system to drive cooling system pressure up and keep water up into the cylinder head. I do this using a CR Racing, Air Spring. YMMV
Skip Pipes
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Most of the 12volt electric water pumps used mainly in drag racing application will not make more than 6psi of pump pressure. They Flow a great amount of water and would work fine in most LSA with N/A motors under 1000hp, A good belt driven pump will only use about 10 hp or less and will give you the added assurance that you are getting enough water flow and pressure.
Pump pressure and system pressure are two very different things.
You can get remote mounted belt driven water pumps that are about the size of an alternator that will give you more cooling options if you cannot get a highflowing stock pump. Stock pumps are prone to cavitate that will lead to loss in HP not just water flow.
http://www.summitracing.com/parts/mez-wp430s
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Stewart told me not the turn the pump over about 5000-5200 at WOT --- so I geared it down to turn 5200 at 8200 eng speed used Gilmer belt so I do not have to worry about slipage
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Tons of good information here, guys.
The reason I'm looking for a remote type WP is for packaging reasons. If I can ditch the OEM water pump, it saves valuable space on the front (crank pulley) end of the engine.
I've always been told that pumps make flow, and that a restriction is needed to generate pressure. The Davies Craig pumps are what has been suggested for my application (Mercedes Diesel). If they can flow enough for a stout Duramax, they should be enough for this MB engine.
Unfortunately, the class (DT) requires a stock or larger radiator mounted in the stock location. I suppose this doesn't preclude the use of a "radiator in a box" setup mounted somewhere else, but some semblance of a factory style radiator needs to reside in the factory location.
The discussion is excellent!
Steve.
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Steve, the radiator has to be there, it does not necessarily need to be used. You could do a tank in the bed or one of the radiator in a box, in the bed.
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Steve said:
I've always been told that pumps make flow, and that a restriction is needed to generate pressure. The Davies Craig pumps are what has been suggested for my application (Mercedes Diesel). If they can flow enough for a stout Duramax, they should be enough for this MB engine.
You are right "kinda" most if not all water pumps for engines are of the centrifugal type, they make pressure by accelerating a mass of water to a high speed and this provides a high flow rate. When a restriction is encountered with a centrifugal pump it does cause pressure but because the impeller on the pump has to have clearance between itself and the housing, any increase in pressure means that amount of slippage between the water and the impeller increases and the actual amount of water that flows out of the pump drops. If you can get the flow vs. pressure curves you will see that increased pressure means reduced flow. Engine driven pumps typically turn at much higher speeds 4-5000 rpm, which means the water leaving the impeller is at a higher speed has more inertia and can sustain higher outlet pressure with out as much slippage (loss of flow) I think that most electric pumps probably don't spin much over 2000 rpm, (correct me if I am wrong here) you might try to double the input voltage which would double the speed, in theory, and maybe sustain higher pressure.
The high flow rate is needed to insure that the water flow through the engine and the radiator is turbulent, the more the better. When Yamaha brought out they killer 750 two stroke road racer in the 70s it had a cooling problem. The fix was Yamaha sent everyone a new set of drive gears for the water pump to increase its' speed and flow rate. Problem solved. High internal water pressure from both the radiator cap pressure and the flow resistance to the water from the pump increase the water boiling temp and the high flow rate reduces or eliminates hot spots around the exhaust valve, r.e. Sparky's experience with his big block. If you use the Davis Craig pumps you need to see what the actual flow rate is when it is connected to your engine and cooling system. I will bet a cup of coffee (retired that's all I can afford!) that is is way under what they rate it for.
Rex
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If you are considering an electric driven water pump I would highly recommend you go to the Davis-Craig web site and look at the application information that they have for each of their pumps and also their tech data. They certainly appear to have done their homework on their units. Each pump technical description includes a flow vs. pressure graph, which is certainly something you can not typically find from other electric driven water pump manufactures. Super interesting info and web site! www.daviescraig.com.au
If you need tech or application information contact John Benson at Davis-Craig.
johnb@daviescraig.com.au . I am not a proponent of electric driven water pumps but if I were to use one it would have to be the Davis-Craig units they certainly appear to be high quality and also know their limits.
Rex
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If the problem with an electric water pump hot spot boiling put a screw in schrader valve somewhere in the system and add 10 or 20 psi of air before the run .
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John, is correct that adding some air pressure will "pre-load" the cooling system to a pressure that will raise the boiling point and help prevent hot spots and pump cavitation. Skip Pipes uses a CR Racing "air spring" which is a container that has a schrader valve and acts as an accumulator for the cooling system.
"I'm with Sparky, run a mechanical pump, and a sophisticated cooling system to drive cooling system pressure up and keep water up into the cylinder head. I do this using a CR Racing, Air Spring. YMMV
Skip Pipes"
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Rex