Electric water pumps

Lateer · Post by **Lateer** » Mon Jun 19, 2006 6:41 pm

I was reading a little bit of info regarding my brother-in-law's car.
Apparently, you can get an electric water pump that bypasses the whole water pump/thermostat thing. It uses a temperature probe to regulate the movement of the coolant through the block and radiator such that it keeps the temperature constant, unlike a thermostat.
If you're interested, have a look at

http://www.oldholden.com/possible/index ... ater_Pumps

?http://daviescraig.com.au/main/display.asp?pid=8

Looking at the benefits, I was curious as to whether this sort of thing would work well for the Tercels.

Anyone heard of/know of/done this

shogun · Post by **shogun** » Tue Jun 20, 2006 8:24 am

youd have to change the alternator because they draw a lot of current, and if you have the space i dont see why not

Lateer · Post by **Lateer** » Tue Jun 20, 2006 6:24 pm

Interestingly enough, Shogun, the website listed reckons these pumps don't draw all that much current.

To the point where you can run them after the engine has stopped to cool the block down quicker without draining the battery.

My point was that they apparently give a horsepower gain and are better for the engine. I was wondering if anyone had actually done it...

Post by **ARCHINSTL** » Tue Jun 20, 2006 8:55 pm

This is a pretty neat idea, depending on the cost/hookup complexity. I've never heard of it before (never an ad in Road & Track or Car and Driver, et al). Is this an Antipodean add-on?
As to HP gain - even if only a pony or two, as with only 62 OE HP back 20 years ago, it would certainly seem a valid addition for our mature cars, again, depending on the cost/complexity.
Tom M.

Gasoline Fumes · Post by **Gasoline Fumes** » Wed Jun 21, 2006 1:44 am

From what I've heard they're actually less efficient than a normal pump. A belt driving a pump is more efficient than a belt driving an alternator and then that alternator powering a motor which turns the pump. You have to consider the inefficiencies of both the alternator and pump motor.

I think the main purpose of them is drag racing with no alternator. Then you get the power gains by eliminating the belt(s) completely.

shogun · Post by **shogun** » Wed Jun 21, 2006 8:26 am

ive seen and installed electric pumps for drag racing, they are very ineficient and also they only work a couple of munites at a time its added weight a lot of it i may say, my opinion they are not worth the hassle

Typrus · Post by **Typrus** » Wed Jun 21, 2006 10:53 am

Well I suppose you have to look at how much power does 15~Amps detract versus the pump itself. We have 55AMP alts, but that means an output of maybe 30 at idle. How much HP does putting that extra 15AMP load drain? Not much I'd guess, as I can't see much of a difference when driving with my 700Watt sub setup on full tilt versus with them all the way removed from the car.

Lateer · Post by **Lateer** » Wed Jun 21, 2006 6:17 pm

The other thing was the variability of the pump flow that interested me.
For instance, when you're sitting at idle at the lights and the engine is getting hot, this pump would be running a lot faster than our belt-driven pumps.
And when we're at full throttle at 100kph down the highway and the radiator is working flat out, then this thing would only be ticking over enough to keep the engine cool.
The really interesting thing for me was that this will kick on after the engine has shut down, cooling the block down and protecting against heat soak.
Another interesting thing for me was the ability to change the engine temperature, i.e. cooler for more power, hotter for more fuel economy.

Basically, I can see the benefits of doing something like this to our somewhat underpowered engines.

And what's 6 amps when compared to Typrus' sub setup? Some people on here have huge driving lights on their machines without too many worries. I personally think that this would be a great idea for our little machines as it gives back a bit more horsepower to the driving wheels and protects our precious engines a little bit better than the older system.

Shogun said that they only work for a few minutes at a time for drag racing. I don't know that we'd be drag racing in our Tercels all that much, and if your pump is doing that, then the thermostat is set wrong. These things should be hooked up to a controller such that they don't stop/start. The websites mention this extensively. What they do is work a lot slower when it's colder and a lot faster when it's hotter by ramping the voltage to the pump.

That's another benefit apparently. No more problems with failed thermostats, as the pump automatically keeps the engine at the correct temperature, no matter what the engine is actually doing. When you're 4wding up a hill and the block's getting a little hot, this would kick in heaps. When you're sitting at the lights and the block's getting hot, ditto. When you're cruising down the highway and things are sitting cool, then this would slow down.

I've talked to a couple of car nuts here in Hobart and they're all for it. One put one on a Holden (GMH) V8 and a Daihatsu Charade and saw decent gains in both. With the Charade in particular, as it gave back a decent percentage of the horsepower to the driving wheels.

Typrus · Post by **Typrus** » Thu Jun 22, 2006 7:51 pm

Heh. If my subs get my brights to visibly dim, and I feel no power change, then I feel that 7 more Amps is negligible. Maybe not for me with my CURRENT (hahahaha) setup but with you guys.... But you do have to start juggling with things if you go much higher at all than stock, in terms of power drain.

According to this site- http://www.spatechnique.com/electric/waterpumps.htm
It drains 90 Watt at 12 volt. Hmmmm... Compared to my 700Watt at 14.4Volt.

But at around $260 USD indicated just for the pump by the same site...... Versus the $26 pulley-pumps.......

Typrus · Post by **Typrus** » Mon Aug 21, 2006 8:58 am

Well, anyone look more into this?
Seems very intriquing to me.
Another point- if this sucker draws 7 Amps at high-draw, and it is made to handle Big-Blocks, then who's to say that peak-draw for our cars wouldn't be closer to the 4 or 5 Amp range? Maybe around 3 Amps more typically? Thats less than the driving lights for crying out loud.

Admittedly, $260 is pretty pricey, but would it be worth it to get an extra couple 10's of thousands of miles out of our cars? With the whole after-run to prevent heat-soak thing, who's to say it might not double the life of our engines? Rapid heating and cooling doesn't seem to do metal well, let alone constant cycles between hot and cold (if the majority of the coolant in the rad stagnates with the thermostat closed, then you suddenly have a surge of maybe 50 degree cooler coolant hitting the engine when the therm opens) So if this thing constantly runs at a variable rate, then the coolant will be pretty similar in temp all the time, preventing excessive hot-cold cycles. Let alone allowing for a gradual, more uniform cooling after the engine is shut down. I can't imagine the effects of having the inside of the block stay hot while the outside gets cold can be very good on the metal.

I wish I had $260 to try this sucker out....

Mac · Post by **Mac** » Tue Aug 22, 2006 12:14 am

saves gas, more power because its one less accessory on the crank, drag cars have been using eletric water pumps for years (usually a motor driving the pump instead of the engine)

Typrus · Post by **Typrus** » Fri Dec 01, 2006 10:48 am

keith · Post by **keith** » Fri Dec 01, 2006 5:53 pm

An electric coolant pump could be more efficient in the same way that hybrid cars are more efficient. A water pump draws a lot of power, especially when you are trying to change the flow of coolant, as in accelerating. The water pump is like a dynamo. If the coolant was circulated at a constant rate, once it got in motion, it would tend to stay in motion, using less power.

The down side to this theory is that the heat generated by the engine is not constant. It is directly related to the amount of fuel burned so the coolant velocity must vary with engine speed and load.

I would think that if this really did work, we would all have cars with them by now.

Typrus · Post by **Typrus** » Sat Dec 02, 2006 12:02 am

Thats a funny thought. Car companies being allowed to use the most efficient things by powers that prefer they keep it as inefficient as possible.

The thing alters its speed by temperature. It has no thermostat in the classic sense. It never stops circulating coolant, it just chages the speed based on need.

Mac · Post by **Mac** » Sat Dec 02, 2006 2:46 am

actually, modern cars, usually high end ones at the moment, are using eletric water pumps. sometimes its a combination of both mechanical and etetric, but the main reason is to get the engine up to operating temp sooner.

I remember being in a X5 in the middle of winter, as it was idlding, you can actually watch the tempature gauge go up, only a few min to reach normal operating temp.

another thing, people convert their V6 contours to eletric water pumps, and i've never heard of any problems.