If you go to Summit racing you will see there are different types of electric water pumps. They pump from 20 to 55 gallons per minute.

Once you convert to an electric pump, that draws 6 amps, you decrease the mechanical load on the engine. The altenator does not have to work any harder to create energy then it did before. What happens is less drag on the engine = HP

As to using a oil cooler and custom radiator. That is the way to go. Your racing your car and providing proper cooling to both liquids very important to your engine "oil and water". I know that I am going with the radiator you mentioned. Im already am running a oil cooler from Tomei and the Oberg tattle tail. Im glad to hear it works. As you can see by my pics my radiator is very small. (webbs1200)

Some of the reasons not to use the pump make no sense to me, but the bottom line is that everyone has some very valid points in regards to this subject.

I would say the key to the origanal poster would be find a way to make way for the radiator to receive the proper air flow it needs.

When you use a EWP, what do you do with the old water pump, make a blanking plate? Is there any later model cars with EWP's? U-pullit might need a visit.

While there are a number of aftermarket suppliers of 'built for the purpose electric water pumps for Chevalays, there are none that i know of for the A series Datsun, so i assume that we are talking about an electricly driven original type pump. That means an electric motor driving the pump via a deive belt, [V type or Gilmer], or perhaps even direct.

If the electric motor draws, say 6 amps as previously mentioned, then that current has to come from somewhere. The battery? Good answer, but since the battery is only a storage device, it needs to be kept charged by something,... & that's the altenator. It takes power to drive the altenator when it is producing current, & that power comes from whatever is driving it. In a car, this is usually the engine.

When you have an electrical load, like lights, aircon, radio, whatever, the load is buffered by the battery, but is carried by the altenator, which passes it on to the engine. Horsepressure saved,... i don't think so, but the electricly driven pump will flow more coolant at lower engine speeds, & if this is what you need, then go for it, but forget the horsepower saving theory, you get nothing for nothing.

I agree with Dodgeman, but I'd like to add my $0.02... 6 amps will get you a 30-37 gpm pump according to the Summit catalog, for a measly $260. You're probably going to need to upgrade your alternator unless you already have one makes sufficient juice to run headlights, heater, wiper and waterpump at an idle. My guess is that's about 30-35 amps, at an idle. Need to understand here, alternators aren't rated at idle, so take that into account. Dodgeman is correct in that you'd have to run a belt drive on an electric waterpump as there are no pumps marketed specifically for the "A". That means with an electric pump, you'd have two belts instead of one. (you do want to keep the alternator, right?)

My opinion is that at idle, it's going to take more power to run an electric waterpump, and at rpm it will save power at the expense of coolant flow. Then you have the complexity of another belt drive and electric motor with wiring. Seems like it would be a whole lot simpler to run an underdrive pulley on the waterpump. Any competent machinist could make one for a fraction of the cost of an electric pump.

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Ummm, guys, you might want to have a look around, even possibly here.

Davies Craig

Interesting. So you need to buy a universal pump and controller. Pump life is approx 2000 hrs. Max flow is about 20 gal/min.

Do you know anyone running one?
What was the cost and is 20 gpm enough?

$400 for an electric waterpump and controller seems like alot of $/horsepower.

Respectfully, operating the water pump via a belt is not correct. UNIVERSAL PUMPS . The manufacturers I have contacted will advise me what universal pump will be best for me when I decide what radiator I will be using. My car will be raced for the most part.

Further you reduce the drag on the engine when you convert to the electric water pump. So you do gain HP. The altenator works no less or no more now that a electric pump is installed. So it is all gain


I have thought of the underdrive pulley for the altenator.

Nothing ventured .............Nothing gained ....watch .........I'll convert to the electric pump and overheat. LOL

PS: Happy Holidays to everyone.

Webbs1200, I am definitely pro electric pumps, however, I do disagree with you about the amount of load the alternator produces.

The alternator will have to produce extra output (total amperage) to operate the waterpump, this in turn will take a little of the horsepower from the engine.

As I mentioned before, energy cannot be created or destroyed, it can only be changed, so the power needed to drive the water pump has to come from somewhere. And before you say it, if the power is supplied from the battery, how does the battery get recharged?

As for $/HP gained, you'd be surprised how little rotating mass you need to removed to get a decent HP gain.

There are also a heap of other factors to take into account like the inertia of the coolant when accelerating, it all adds up to extra HP at the wheels.

I think L18_B110 hit the nail on the head with the fan issue.
As for water pump. The pump is there for the sole purpose of pumping coolant through the engine. Since engine heat is in direct response to engine speed, it is natural that at lower engine speeds heat production is less, therefore less coolant flow is required.
The radiators job is to dissipate coolant heat as quick as possible. If it cant meet the demand placed upon it at maximum heat and flow. Then the radiators operation is insufficient. Everything below this temp is satisfactory, as the engines heat it governed by the thermostate.
Electric pump only has one flow rate. The radiators job is still the same and the thermostates job is still the same. A constant flow rate is only really suited to a specific engine rpm. Any rpm below this is just wasted energy on the pump and any higher rpm will mean an insufficient flow rate. So naturally electric pump flow rate will have to suit maximum engine rpm, to meet heat production demands.
Good for an engine that stays at a specific rpm. Any rpm less means less heat, thermostate reduces coolant flow through the engine and that reduced coolant flow places a load on the electric pump. Catch 22, more load on pump means more current draw, therefore more load on the alternator.
Power dont come for free. It takes more energy to produce a specific amount of energy.
Maybe there is a reduced load power gain with an electric water pump, but how little does it really equate to?

My bet is and electric waterpump was first used buy a drag racer who wanted to reduce engine loads by removing the fan belt, but still wanted a quick means of coolant flow on the return trip to the pits