Electric Water Pump

[RWBAUMAN]

I am in the process of replacing my water pump on an 89 Esprit. Has anyone used one of the new electric water pumps? A review on the manufacturers web page (www.fordmuscle.com/archives/2000/08/electricwaterpump/index.shtml) makes the pump look very attractive for increasing HP and improved cooling. Any thoughts?

>>> Edited by RWBAUMAN on Monday 15th September 13:59

[GreenV8S]

I've got one of these on the V8S. Increases the flow at idle quite usefully, but they don't flow anything like enough to completely replace the water pump (despite what DC may say in their adverts). (To clarify that, it flows enough through the rad to keep the average engine temperature down, but doesn't flow anything like enough to prevent hot spots in the heads.)

[lotusguy]

Hi,

I suspect that what GreenV8 says is correct. But to move from the realm of the anecdotal to real facts, you'll need to find and compare the flow rates of the stock waterpump at various RPMs, including the max flow at top RPM and compare it to the constant flow of the electric pump.

Also, you must learn if your alternator is capable of carrying the additional load and whether it's increased draw on crank HP exceeds the current draw of the stock pump and alternator combined. Due to the inefficiencies of current alternators (the best convert 30% of the power they draw into useful electricity, most are like 22% efficient), yours robs about 3.3HP to produce 90Amps of electricity, while the waterpump robs only about 0.4HP (more efficient) totalling 3.7 HP. Increasing the alternator's load an arbitrary say 20 Amps, will increase the HP draw to the neighborhood of 4.03HP.

Sounds like a small number on a car which produces over 250HP, but remember that it only does this at one point, or narrow range, in the RPM scale. At ranges much lower than this, the draw can become much more noticeable.

I'm not trying to discourage you, just pointing out some of the other things you must consider to insure that such a swap actually results in better performance, or at the least not poorer performance. Happy Motoring! Jim'85TE

[GreenV8S]

lotusguy said:

Hi, I suspect that what GreenV8 says is correct. But to move from the realm of the anecdotal to real facts, you'll need to find and compare the flow rates of the stock waterpump at various RPMs, including the max flow at top RPM and compare it to the constant flow of the electric pump.

I did that (compared the flow characteristics to the low volume water pump on my RV8) before drawing my conclusions. (Incidentally, the current draw is 7.5A, this is a 100W electric pump producing maybe 80 W of mechanical power. The mechanical water pump consumes roughly a Kilowatt of mechanical power. In terms of actual volume flow against realistic back pressure there is absolutely no contest.)

[RWBAUMAN]

Thanks for the info. I think I will just stay with the stock water pump. The stock water pump was always adequate for my use.