Electric water pump

[Sunaj]

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

[Daox]

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.

[serialk11r]

Originally Posted by California98Civic

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.

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.

[California98Civic]

Originally Posted by serialk11r

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).

[ChazInMT]

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.

[Sunaj]

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.

[Daox]

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.

[t vago]

Originally Posted by ChazInMT

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.

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.

[ChazInMT]

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.

[ChazInMT]

Originally Posted by t vago

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

Baseline Testing - Do Water Pumps Suck Power?

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

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.