Electric water pump
 

Spent the last few hours reading threads, and wondered how difficult it would be to convert the pump in my 2000 chevy malibu 3.1 to electric.

I could manage with a pump from a Toyota prius? They can be had for 70 bucks on eBay. In theory could just about any water pump work? Then, how would I wire it?

Obviously I could get the electrical connector for it and wire the positive to the battery and ground the pump? Would this create a situation where the pump constantly runs even when the engine is off? How could I wire it so that it comes on after cars been started?

Then would it be suggested that I use a resistor to slow it down so that it isn't running full speed all the time? Or do I want it at constant full speed

Would be nice as I've already deleted the ac system on my vehicle, wasn't working anyway. If I can switch to electric pump, then that allows for Mechanical pump, idler pulley and PS delete leaving just the tensioner crank and alternator config

I would suggest attaching a motor directly to the stock factory pump and bypassing the belt if possible.

The water pump only needs to turn at maybe 1500rpm, you can find a cheap brushless motor and RC plane controller to do the job, or even a brushed motor (I would go brushless for reliability).

Trying to lose weight in the engine bay so don't really want to go that route if I don't have to

Actually, you're adding weight either way. But, instead of adding a pump and a motor, you'd just be adding a motor. :)

Either way, you'd want some form of controller so its not running full tilt all the time.

I've heard of people simply wiring as described in the first post and adding a resister. Is this not possible?

Its possible, but its still just a single speed. If you want to do it properly and efficiently you'll want a controller that monitors a few things and modulates speed based off those sensor inputs.

And how much am I looking at? Don't want to spend over 200* bucks for this setup honestly and I'm aware it will only be a single speed action.

Also., any water pump could work right?

If you don't have a proper controller, you might not see any of the benefits an E-pump can bring, in fact you might go backwards.

A pump running enough to cool at WOT right from cold start will only slow warm ups, and with the T-Stat closed, that's a lot of load on the pump/motor/battery/alt.

Etc, etc.

I don't know why people are so insistent on DIY solutions when a Davies Craig setup is only a fraction over $200 and comes with a proper controller, warranty and adapters for certain engines.

Wheres this davie craig setup you speak of? got a link?

I assume one of the kits on his website.. just came across this one..

Electric Water Pump EWP80

I use electric coolant pump and built a multi speed controller using resistor then PWM.
I actually do not recommend electric water pumps.

why dont you recommend them?

Because they can be expensive. You cant get them at a local parts store. They need electrical power. They need to be wired into electrical power. Its hard to tell when they have stopped working. They may pump too little coolant. They might pump too much coolant. Unless you can get direct bolt on you have to fabricate stuff. You will have to rearrange your accessory drive, which involves fabricating brackets most of the time. Its an additional load on the limited power the electrical system can provide. The weigh more than the belt driven pump.

And maybe more reasons that I cant think of right now.

One of the reasons I do like the electric coolant pump is that I can use it to circulate coolant through my 5500 watt coolant heater.

I just posted a thread very similar to this and THEN found this one. Ugh. Thanks for the link to the Craig Davies pump. My question is slightly different than yours. I'd love input:
http://ecomodder.com/forum/showthrea...ate-33925.html

hmm, now that i've seen your thread, I am really contemplating just getting an electric motor and doing it that way. Any tuts anyone?

Are you attempting to reduce the load on the engine of the original water pump?

I would like to do away with mechanical pump for a few reasons. One which is to reduce mechanical load on engine, and to reduce weight if supplemented with a lighter, more efficient electric pump. My AC system- deleted. I want to delete Power steering as well, cant mainly because the pulley helps connect belt to water pump. Getting an electric pump would allow me to do just that. Potentially better cooling. Another reason- I love space in the engine bay. Overall, I seek a near beltless design. Engine has aged/ lost power and in the process reducing things I dont "need" until I have the funds and time to rebuild. At the end of the day bare minimum I'd like the belt only running the alternator. i believe the less crap my engine has to carry with it the more miles I can queeze out of it ( until i get the time and money to rebuild) since not many things are bogging it down, mechanically Oh, and anther reason. I love simplicity. Its my only ride to and from a job i dont mind going to every day

I have seen guys claim test results, even dynos, that show their electric water pump set ups save anywhere from 3-7 hp over the mechanical kind.

EDIT: here is a pump controller which varies speed of pump, controls rad fan, and monitors temp (also has alarms). The full kit with this unit is about $450!
http://daviescraig.com.au/product/ew...bo-part-no8807

Jeez that's expensive

Here is the setup I've concocted. It never went into the Metro due to time, and now I'm going to be selling the car. It very well may find its way into the Insight though. Cost of parts is roughly $70 if bought all new. I think you could get away cheaper if you scrounge.

http://ecomodder.com/forum/showthrea...eap-29896.html

I did read through that threat at one point. Not too sure how to program though

Cheaper to learn to program than buy the davies craig controller, plus fun too. :)

You'll likely get help here too if you're willing to do some legwork and find info on your sensor outputs.

Yes that's correct, but at typical engine speed the power requirement is much lower. In terms of dollars spent per hp gained/saved, it's pretty good, but often quite a lot of hassle due to how the water pump is integrated into the block.

Since the water pump is a necessary accessory, I am more okay with it running off the belt than a PS pump, but would try to find an underdrive pulley to cut the losses a bit, unless rerouting the belt is easy. 20% underdrive = 48% less power, in theory at least, and if that turns 3hp into 1.5hp or 5hp into 2.5hp at redline, I can stomach that.

The idea is alluring, and I am almost willing to throw money at the $459 system, but this is my DD and I need to complete service and some other mods that are incomplete this weekend so I can get back on the road next week. So this is not the responsible, practical path right now.

So, I am passing on the idea (for now and the foreseen future but not permanently).

I don't see how everyone is neglecting the fact that in order to pump the water it still requires power. We argue against HHO generation all the time because the electricity required to divide the water molecule requires more power to generate than the added fuel it provides can overcome.

In that light, the electricity to power the pump is going to generate a greater load on the alternator so it isn't like the load just disappears. Also, direct power from a belt for an accessory is always more efficient, at a given load, than converting engine power to electricity than using the electricity to run the load.

I can see how a thermostat delete and a variable speed motor could show some benefit in that it would be only using the amount of cooling system flow rate energy required to keep the engine at proper temperature.

Then there's the "What happens if it quits working" variable.......I dunno about you, but I usually need to get to where I'm going when I set out on the road. Having something go wrong, or worrying about if the system will be adequate and reliable would drive me to an early grave. There is a HUGE amount of reliability comfort I get knowing everything should work fine, and I think I'd pay the extra $100-200 dollars you might save, when it is all said and done, to know I don't have to worry as much about the cooling system.

Even if that's the case, the question then becomes, though greater electrical load is required to run such a setup, will it produce more or less engine drag compared to mechanical setup? Such a setup that relies on RPM. As for efficiency, I'd like to think an ewp could streamline the cooling.. Especially with a controller of sorts. Set a constant solid value /voltage, and have it run at a set continuous speed instead of being RPM dependant. That's efficient enough for me.

Even if so, I think in my situation, it's still something I want to pursue. The reliability factor boils down to intent purpose and product of choice, as well as integration. After years people are still running their ewp setups with no problems. Sure, some have prematurely failed.. For reliability- I had a new mechanical pump seize on me once causing my engine to near overheat. Current pump has not failed me yet, but I want to experiment


If the thing quits working, then it just does then from there I reconsider based on longevity.

As I build my e-pump setup I was going to test the pump power consumption at the full range of engine RPMs. This would allow you to see how many watts the pump uses at idle, cruise, and high rpm acceleration. After that, the plan was to start optimizing it and reducing power consumption as much as possible. I'm pretty sure there is a lot of room for improvement here over belted systems. Of course, you are paying the alternator efficiency penalty (if you use an alternator) by using electricity vs mechanical power.

Adding an e-pump does have a couple benefits that you simply can't get with a belted pump.
1) Heat with your engine off. This is a fairly big one for me as I live in a fairly cold environment in winter. I sometimes have to leave the engine on to defrost the windshield, and heating the cabin is challenging and annoying with engine on/off cycles. The e-pump completely solves this.
2) Preheating. The e-pump gives you more options for preheating your engine. You can circulate the coolant while it heats up. This could be used for cabin preheating, or transmission preheating as well. Or, you can do like the Prius does and use a thermos to store hot coolant. Or, you can use a crazy big heater and preheat the engine in 10 minutes like Oil Pan 4 has done. Or, you could perhaps try to circulate coolant through a solar hot water collector like NoD has suggested. It just adds a lot of flexibility for preheating and using and moving the heat you have.

As you know, the trouble is that the water pump load will change only as a direct result of engine speed. At that point, it becomes a debate whether to continue to mechanically drive the pump at a 1% loss due to the drivebelt, or electrically drive the pump at anywhere between a 30% to 45% loss from conversion from mechanical energy to electricity, but gain a net 1% to 3% increase in fuel efficiency at the same time.

This Hot Rod magazine article has a rather interesting take on electric water pumps.

Baseline Testing - Do Water Pumps Suck Power? - Hot Rod Magazine

I gathered, from reading the article, that it might be best just to get an underdrive pulley.

You need only one input to a controller to vary the speed, coolant temperature. You can't run too cool or you loose efficiency, you can't run hot because...duh.

So a constant speed electric motor would not be efficient because you would be wasting energy if you were throttling the flow with a thermostat, it would be less efficient than a regular belt drive pump. If you ran it slow enough to be efficient at low speeds, than it would cook your engine on a hot, high heat load, day.

Trust me on this, it takes POWER to circulate the coolant, the power must come from somewhere and just because it is an electric motor driving it now does not by any stretch mean you are using less power. For a given flow rate of coolant, the power required to drive the electric pump will be more than the belt drive pump, by a lot, ~30% shooting from the hip.

Don't get caught up into thinking that just because the engine isn't turning it with the belt, the load goes away.

As I said, there "May" be room for an efficiency gain if you vary the speed based on coolant temperature, and the current set up is really wasting a lot of energy due to spinning the pump too fast for nominal coolant system load and the thermostat is throttling a lot.

But the efficiency gain I think will be small enough that you would have a hard time seeing it on your MPG logs, and the payback time for even a $100 outlay would be very long. If you figure a 5% efficiency gain (Really a pipe dream that) and $3 gallon gas, and a 30 mpg base, it would be 20,000 miles before you break even on the $100 cost. You will not have saved a dime for the first 20,000 miles, after that, you'd be "Saving" $100 every 20,000. If the efficiency gain is smaller 1-2% it will be 60k-80K miles before you see your first penny of benefit.

Don't let facts stand in the way of a good dream I suppose. I post this here only to give others who may be contemplating this more food for thought.

If you think I'm wrong here, by all means let me know where the facts are not correct, it is entirely possible I am not taking something into consideration here. But please, do not let me know how I may be wrong without facts.

Good article. My take on it is that they're running the engine at full power, and that is where a mechanical pump would be the least efficient, at lower RPM the power to spin the pump would be less. Since ~93% of the time our engines are running at cruising speed, I don't think the parasitic drag from coolant flow is really all that great, and since an 8 amp current draw is only about 100 watts, 1/8th HP, I don't think we're talking about a very large load here at all.

This only supports my theory that it will be very difficult to see an efficiency gain from this.

Agreed that a larger pulley would be a way to see real gains, but the ability to cool the engine on the hottest of days may be compromised.

My set up would powered off the grid, which for me means wind power. I don't run the alternator much, (except during DFCO and very long drives). So an electric pump means reducing the carbon footprint of the car, overall.

The engine still needs coolant circulation even when the thermostat is closed.

Worth remembering that at high rpm, the eddy current losses of the alternator are very high and the efficiency is usually under 50%, so that cuts the peak power saving down a bit.

At idle the mechanical pump is almost certainly more efficient than the electrical pump. However 50% greater pump speed = 1.5^3 = 3.375x as much power, so any time the engine is more than just barely above idle you're saving power with the electric pump.

I had a Meziere EWP on my GTO for a few years
loved how I could cool down the engine between races (didn't like how it killed my battery a few times)

as well as the 16RWHP it added (checked by dyno)

but it failed after about 3 years (25K miles)

they don't seem to be a great idea for street applications

i have my davies craig water pump since nearly 4 years and about 35kmiles. i had no problems so far

How's it setup?

He has one of the greatest mod threads on this site, and if you read post number one you'll find he has indexed everything. Click "thanks" on his posts and show some love... echo-francis is one of our best diy engineers on this site. Check out his thread: http://ecomodder.com/forum/showthrea...tml#post264300

Thumbs-up! Way up!!

A belt-driven water pump is mechanically the same thing as an electric pump, minus the electric motor. There are plenty of reliable electric motors, so there's no reason it can't be a good idea for a street car.

Your Mezier pump may have failed, and BMW N54 pumps may have sucked, but millions of Priuses use an electric pump that is quite reliable, and all the new VW/MB/BMW cars are using electric pumps.

So, studying echo-francis's fuel log and EWP install shows it was associated with improved fuel economy. But it is hard to tell how much of the improvement was due to the new pump because he did a bunch of mods at once. The EWP was installed Sept 2012. In March 2012 he had recorded 58.59 MPG (US) and in October he recorded just over 63 mpg. But there were a few mods in between, like wheel skirts for one. So maybe it was worth anything from 1-3mpg in highway driving conditions? BTW, the install was a bear. Here is the install post: http://ecomodder.com/forum/showthrea...tml#post328930

I can also say that when I put a 25% UDP on my Dakota's engine back in 2011, I did not notice any real difference in fuel economy.

Then again, I did not (and do not) really rev the engine that much past 2000 RPM for any real length of time.