Balmar alternators literature says to calculate 1HP loss for every 25amps of alternator power at full power. This excellent article states that 1HP=745.7 watts. A thread on Fuel-saver.org uses this calculation:
Amps x Volts = Watts
Watts / 745.7 (one HP) = Electrical HP Produced by the Alternator
HP x 15% Efficiency Loss = HP Loss
HP + HP Loss = Total HP Used

Example:
57A x 14.9V = 849.3 Watts
849.3 Watts / 745.7 = 1.14 HP
1.14 HP x 15% = 0.17 HP
1.14 + 0.17 = 1.31 HP Total

So, it should be easy enough to guesstimate the HP losses from using an electric fan or waterpump, and compare that to the tested gains from eliminating the mechanical devices.

Except for the relatively high initial cost, it seems that an appropriate electric water pump and electric fan offer realistic and reasonable gains.

-Moose

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1966 Clark Cortez, Industrial /6

Electric fans are a good, proven way to reduce mechanical drag and improve cooling at idle (if done properly). In fact my '01 Dakota idles so slowly (for fuel economy reasons) that the clutched mechanical fan is inadequate at idle and there is a factory electric fan that comes on with the AC and some times in the drive-through.

I do not know of any factory application that uses an electric water pump as the primary coolant pump. I feel that the cost to benefit ratio of an electric water pump is much too low and the potential reduction in reliability is a serious drawback.

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Joshua

I have a Proform electric water pump/fan on my non slant mudbogger. I love it.

In a race vehicle you are either idling or at WOT....the factory pump is actaully designed for cruising speeds. The lectric pump flows at a constant rate allowing the rest of the cooling system to operate in an efficient and consistant manner. Warm up and cooldown are far better controlled. Cooling during runs is far more efficient.

In a street car an electric water pump is a complication. An electric fan has many avantages. Including light weight , fan control, cooldown.

The Valaint has no fan.....but it is always traveling at some speed and the car moving at 30 mph is enough to keep it cool.

2.5 hours and a ferry ride to the nearest drive through or stoplight is a factor. Your neighbourhood may be different.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

I'm talking about removing my fan blade and using an electric one..

I wonder if there's a way to put a clutch on the fan blade or factory waterpump :p probably wouldn't be worth the hassle or be as efficient compared to using an electric fan and pump..

I could figure out what the crank rpm at cruising speed is and keep the electric motors to about that to try and keep them as efficient as possible..

After Christmas I'm going to go hardware shopping

The water pump needs to be running full time to prevent hot spots so no clutching the pump. The simplest thing is to just leave the pulley and belt on the water pump and remove the mechanical fan.

The Ford Taurus has a really good electric fan. I have a Taurus fan I bought in a wrecking yard for $12 or so and although it doesn't come with mounting hardware like an aftermarket fan I'm handy enough to make it work and the price is right. It's a two-speed fan and even on low it moves a lot of air. You will need good relays and heavy wiring to do the job properly.

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Joshua

Yes! There was! The search button is your friend.

click me

Excellent! That link has been bookmarked

Josh is right. Figure out what the perfect fan would look like and off to the Pick-Apart. I think I paid less than $20 for the one I wore out a decade ago on the Valaint.

I put mine in front of the rad......it freewheeled itself to death as I never turned it on.<shrug>

I have driven 10s of miles at a time with no fan belt.....the water pump being driven by the freewheeling fan.

Electric w/p on a slant street car is like training wheels on a golf cart.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

The Chevy HHR fan is an excellent choice for A bodies, but I have never seen one in a Slant application. Not sure if there is enough room for it since there is so little room between the radiator/water pump.

In no way would I trust an electric water pump on a true daily driver street car. Risk is way greater than any possible gain.

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Official Cookie and Mater Tormentor.

Bing!

Someone said it right.

CJ

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Part of Tyrde-Browne Racing

I've done quite a bit of research on the Davies Craig electric water pumps, and found a number of people who have run them for a few years on daily drivers with no problems. They are also being used on some OEMs (i.e. Connaught GT Coupe in Britain). The cases I've seen where they failed were all improper installation (usually leaving a normal thermostat in place).

I've bought one with the digital controller that I will use on my Cortez when the rebuild is done. I'll also be using the small booster pump, for the head/heater circuit to keep some constant flow. I will keep a spare pump, so if it fails, I wont be stranded. I'm still a couple months away from getting the engine going though. (at least 4 weeks until I get the crank back).

A number of you, who's opinions I value and trust, have stated that electric water pumps are unreliable for a street car. Would you please give some more background to that opinion?

I'm going to try it either way, but I'd like to understand where you think the pifalls are.

-Moose

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1966 Clark Cortez, Industrial /6

An electrical failure of some sort surrounding the pump circuit can park you, or fry your motor. Belts are power hogs, but are much more reliable for the long haul. I've seen plenty of belt driven electric pumps throw belts. Not so many OEM belts jump. It happens, but it's not something that is common.
Mark built a direct drive unit. Likely better, though he will be subject to wiring, fuse and connection issues. If the pump motor fails out on the road somewhere, repair may be a bit of an issue. (He doesn't drive the car long distances, so this is much less of a risk for him.)
Sure, folks do run electric water pumps on the street, and there are OEM equipped cars running them. The OEM's have mechanisms for catching a failure more quickly than watching the gauge come up, or catching it on an idiot light.

For a street car, the gains are much lower than a track car. The engine isn't operating at high power output in a street car the majority of the time. If your only using 20 HP chuffing down a road at 2100 rpm, the pump doesn't represent nearly the fuel use or power robbing drain you see at 6000 rpm screaming through the traps.

CJ

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Part of Tyrde-Browne Racing

I was thinking the same thing. Toothed belts require much less tension and require less power to drive. I expect to change the race car's V-belt water pump drive to a toothed belt. It will also then match the oil pump drive. Both the water pump and oil pump will turn about 1/2 crankshaft speed.

Also, how is an electric water pump preventing hot spots when it's switched off?

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Joshua

Most of the guys leave the water pump running after shutdown. The ignition can be cut without dumping the main, or the pump and fan switch.

CJ

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Part of Tyrde-Browne Racing

Under what phase of engine operation would you not want to run the water pump? Post-running cool down would be a good time to have it on, but I can't think of a good time at all to have it off.

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Joshua