electric water pump

[GreyGoose006]

hey,

how mainstream are electric water pumps?
ive been thinking that the typical mechanical water pump used in cars is rather stupid.
you draw engine power to drive a pump that, when the thermostat is closed, does nothing.

if you had an electric water pump, you wouldnt need a thermostat, just a sensor to tell the water pump to turn on at a certian temperature.

mini uses electric water pumps in their new cooper, but is anyone else doing it?

benifits i see are:
quicker warm up
cooler running temps
possibly cheaper
less engine drag (yes i know, the alternator... but in general)


what say ye?

[UncleBob]

the advantages are really slight. I've personally never known anyone to run one on the street, only drag racers who had too much money to waste

I personally like having vital system connected by mechanical operation of the crank. It removes the question of partial part failures that destroy your engine before you become aware of it. For example, I would never buy into a oil pump that was electric

[wrightz28]

Goose, if you're thinking of running one on your iROC I wouldn't. Look at what they were designed to run from the factory, the fan doesn't even kick on until 230-235

My 85 had cooling problems when I first got it. And i will tell you, the slightest deviiation in ignition timing or a fan/relay going kaput and you are in a world of hurt. Remember, bake a motor, it may survive, but a trans almost never survives.

For the pros of running a electric pump, talk to cuda_dude in our section, he runs one (walbro?) on his LT1.

[GreyGoose006]

well i was not seriously thinking about it but i was considering it.

for the overheating issue, i have a 4 core nascar radiator in there, so it doesnt have to worry too much about that.

i was thinking more along the lines of new cars though

[curtis73]

Electric water pumps are mostly a race thing. They can free up a few hp at the expense of reliability (both in the pump and the charging system). At least with today's technology, there is no reason to run an electric pump unless absolutely necessary. Engineers of new cars try to avoid them at all costs unless space absolutely requires it. I know that back in the day, VW completely redesigned their entire engine; block, heads, accessory drive, everything; JUST to make space to run a mechanical pump.

Maybe in the future they'll be mainstream and reliable, but today's mechanical pumps are paradigms of reliability and cost effectiveness. Running an electric will just cause headaches. They fail and you're left sitting; hopefully you notice the overheating before it damages anything. With a mechanical pump, they warn you with noises and wear long before they quit pumping water.

benifits i see are:
quicker warm up
cooler running temps
possibly cheaper
less engine drag (yes i know, the alternator... but in general)

1) They won't offer quicker warm up. Electric pumps run all the time, just like mechanical pumps.
2) They also won't make the engine cooler. As long as there is enough flow, more is not better. Faster water means it spends less time in the radiator shedding heat, and a proportionally shorter time in the block absorbing heat. Theoretically, as long as there is adequate flow, it doesn't matter how fast its going. The other thing to consider is that electric pumps have a fixed speed. Mechanical pumps flow more water based on how much right foot you use. Electric pumps don't. They may be inadequate at highway speeds.
3) At least right now, electrics cost way more than mechanical.
4) It will lower engine drag, but only on the order of a few hp. I'd much rather give up a few hp and not have the headaches of the electric pump.

[Steel]

Curtis: dont forget to add that it will only increase the load on the alternator as well, so i really can't see that much hp being freed up. Until they start coming out with 42 volt electrical systems, it's not worth the headache considering the perfect simplicity of the modern mechanical water pump.

[KiwiBacon]

The problem I see is the speed is uncoupled from the engine.
So they probably are pumping too much water at low engine speeds and not enough water at high engine speeds.

Also when the thermostat is closed water is circulated through the cooling system to even out the temperature. It's not simply blocked off.

[Moppie]

You could always fit the electric pump with a PLC tied to the engine speed

[GreyGoose006]

well all i know is that on the new mini, there is an electric waterpump contraption that DOES allow faster warmup by not running until a certain temp is reached.
it wouldnt be hard to put a temp dependant pot into the system to allow different speeds.
Variable frequency motors are expensive, but would save power by allowing variable speeds and not wasting it in a pot.

[curtis73]

I can't imagine that being a good thing. An engine needs water flow. You can't just not pump water. The last time they did that was in a Model T with 23 hp. Its not like it heats up faster, it heats up unevenly.

Think of it this way. When an engine is cold with the thermostat closed, it circulates coolant around the engine, not the radiator. If you stop the flow, it won't heat up faster, it will just superheat coolant above the chambers and cause problems. I imagine the electric pump on the mini might hold off for a short time, but to wait until the engine is hot to start flow would mean horrible reliability, if not worse.

[Moppie]

Originally Posted by curtis73

I can't imagine that being a good thing. An engine needs water flow. You can't just not pump water. The last time they did that was in a Model T with 23 hp. Its not like it heats up faster, it heats up unevenly.

Think of it this way. When an engine is cold with the thermostat closed, it circulates coolant around the engine, not the radiator. If you stop the flow, it won't heat up faster, it will just superheat coolant above the chambers and cause problems. I imagine the electric pump on the mini might hold off for a short time, but to wait until the engine is hot to start flow would mean horrible reliability, if not worse.

Curtis, try heating the water in a sauce pan by holding only a small part of it over a heat source.
If you put something in the water so you can see it flow, you will notice it flows away from the heat source as it heats up, and cold water moves in, until all the water is evenly heated

[curtis73]

That's very true, but we're talking about alot more BTUs than a stove. Water is highly conductive, but one of the worst things for an engine is to have uneven heat.

Try filling an iron skillet with water, then heating it with an oxy-acetylene torch right in the middle of the bottom. It won't take a minute before it shatters. If you swirl the water around in the skillet, it removes heat faster and distributes it to the rest of the pan. The water won't reach peak temperature any faster or slower, but it will prevent the pan from shattering. That was my original point. You're still putting the same heat into the water, but moving water removes and distributes heat much better than still water.

I agree that water will take heat away, but in this case its not nearly fast enough. It wasn't even fast enough in the 23-hp model T

[wrightz28]

Originally Posted by GreyGoose006

well all i know is that on the new mini, there is an electric waterpump contraption that DOES allow faster warmup by not running until a certain temp is reached.
.

Although I'm not overly ramiliar with that setup, what I can guess is that the pump contains a internal by-pass valve in place of the conventional one used more commonly today on a mechanical setup.

[UncleBob]

I can't speak for the 2008 mini, but the 2007 was still using a traditional belt driven waterpump.

Many of the european cars use a small electic waterpump as a after-cooler, to prevent boiling of the system after shutting it off. This might be what he was refering to

[GreyGoose006]

ok... i misread.
it has a magnetic clutch that disengages the waterpump, which is belt driven.
(i read it in a hurry)