Electric water pump, worth while?

[OliverSedlacek]

I think there's quite a lot of aero benefit to be squeezed out the cooling system, mostly by carefully ducting the air to and from the heat exchanger. One goal has to be to reduce the size of the radiator to its practical minimum. Does an electric water pump help at all? I'm thinking that the decoupling of the water pump speed from the engine speed should allow for quite a lot of improvement, if done right!

[oil pan 4]

I tested it twice and I'm going to say no.
Electric water pumps have a habit of pumping less than a mechanical one at speed.
If anything you want a bigger radiator with an electric cooling pump.
They help warming up a car in cold climate, you can plumb in a hot water heater element to the cooling system like I did and defrost your car and warm up the engine with out burning any gas.

[newbvetteguy]

Originally Posted by OliverSedlacek

I think there's quite a lot of aero benefit to be squeezed out the cooling system, mostly by carefully ducting the air to and from the heat exchanger. One goal has to be to reduce the size of the radiator to its practical minimum. Does an electric water pump help at all? I'm thinking that the decoupling of the water pump speed from the engine speed should allow for quite a lot of improvement, if done right!

I think there's a good bit of POTENTIAL from an electric water pump that can be PWM controlled and having advanced control over both the water pump and electric fan control.

Davies Craig has done a lot of work in this space and hold some patents that probably shouldn't have ever been issued, but the ability to run maximum engine heat at highway cruise by slowing down the water pump and fans -WILL improve highway MPG, and then you still have the ability to spin them as fast as possible when the cooling is needed.

-A lot of guys running Ethanol / Methanol also use the Davies Craig electric water pump and controllers so that their engines heat up quicker to help deal with cold running temps and ethanol / methanol.


Like OilPan4 said, though in a performance application an electric water pump can't hope to cool as well as a mechanical pump and will generate far less pressure. -For low engine RPM cooling, electric water pumps are wonderful, though. (Although their reliability / max lifetime is pretty pathetic compared to their mechanical counterparts.)

-I increasingly like the idea of just running an efficient mechanical pump and using brushless fans with advanced PWM control and /or grill shutters like many of the OEMs are doing to control temps intelligently. (The cost and lack of reliability in electric pumps makes them a tough sell...)


Adam

[mohammad]

random list of cooling system ideas i have.

1. You could run the electric pump while car is off to more effictively warm up engine via block heater. But they also make thermosiphon coolant heaters that do this aswell.
2. you could potentially combine this with an alternator delete and stop using the serpentine belt all together assuming your car had a serpentine belt driven water pump.
3. You could try and make the engine warm up faster by adding a valve to the heater core so it isn't warmed up when heat is not needed.
4. You could buy a thicker more fin dense radiator to reduce the size of radiator needed. But this has its own aero dynamic losses
5. You could increase thermal mass of the cooling system so that short bursts of heat like flooring it to pass a car won't cause your car to overheat. You could do this using a massive coolant tank like this one: Link removed as i dont have enough posts on here
6. in alternative to above you could wire the car to turn on the cabin heater when the engine starts to overheat.
7. you could stack an oil cooler in front/behind the radiator to have more cooling with less frontal area.
8. you could use a smaller pulley on the water pump to overdrive it and make it spin faster.
9. you can design your system with the expectation that the car will overheat in certain situations.

10. Instead of doing all this work you could go buy a toyota prius which has adaptive aerodynamic grill block which is basically what you want.

Fundamentally your car will likely over heat when the rpms are high. The engines already spinning the water pump very fast, im doubtful you will go much faster with your electric setup. You will also have some very high losses. 40-50% at the alternator, then more at the pump as it produces heat.

I was wondering what would happen if you integrated the radiator with the turnk lid and used a combination of a fan and the natural vacuum when the cars in motion to have cooling with virtually no aerodynamic losses.

you can always try to dissipate heat like the old porsche race cars did. By running oil through the car frame.

Alot of vehicles like the prius already use an electric water pump but thats probably more for the reduced warm up time.

[freebeard]

Air cooled rules, water cooled drools.

[OliverSedlacek]

Originally Posted by freebeard

Air cooled rules, water cooled drools.

Well I've got an air cooled engine and it can overheat!

[freebeard]

It was a joke. Sorry.

I had a bad experience with the diesel Dasher. It didn't drool, it sprayed the underside of the hood. Repeatedly. Replacing conformal OEM hoses with cut-from-a-roll. It has one hose that's 3/4" on one end and 1/2" on the other. ???

[oil pan 4]

Nope alt delete and electric cooling pumps and fan don't go well together, been there done that unless you are adding 100lb of batteries.

[mohammad]

Thats not exactly true, 100AH 12V LiFePO4 Batteries are only 31 ish lbs. I think that would be enough battery capacity to make it through what most of us will drive in an average day. If not the alternator can always be re-connected. Of course power draw can also be reduced with LED lights and the like.

[OliverSedlacek]

Originally Posted by mohammad

random list of cooling system ideas i have.

1. You could run the electric pump while car is off to more effictively warm up engine via block heater. But they also make thermosiphon coolant heaters that do this aswell.
2. you could potentially combine this with an alternator delete and stop using the serpentine belt all together assuming your car had a serpentine belt driven water pump.
3. You could try and make the engine warm up faster by adding a valve to the heater core so it isn't warmed up when heat is not needed.
4. You could buy a thicker more fin dense radiator to reduce the size of radiator needed. But this has its own aero dynamic losses
5. You could increase thermal mass of the cooling system so that short bursts of heat like flooring it to pass a car won't cause your car to overheat. You could do this using a massive coolant tank like this one: Link removed as i dont have enough posts on here
6. in alternative to above you could wire the car to turn on the cabin heater when the engine starts to overheat.
7. you could stack an oil cooler in front/behind the radiator to have more cooling with less frontal area.
8. you could use a smaller pulley on the water pump to overdrive it and make it spin faster.
9. you can design your system with the expectation that the car will overheat in certain situations.

10. Instead of doing all this work you could go buy a toyota prius which has adaptive aerodynamic grill block which is basically what you want.

Fundamentally your car will likely over heat when the rpms are high. The engines already spinning the water pump very fast, im doubtful you will go much faster with your electric setup. You will also have some very high losses. 40-50% at the alternator, then more at the pump as it produces heat.

I was wondering what would happen if you integrated the radiator with the turnk lid and used a combination of a fan and the natural vacuum when the cars in motion to have cooling with virtually no aerodynamic losses.

you can always try to dissipate heat like the old porsche race cars did. By running oil through the car frame.

Alot of vehicles like the prius already use an electric water pump but thats probably more for the reduced warm up time.

A number of interesting ideas there, not all suitable for my car though. I've got an oil cooler mounted in front of the water cooler, but it's probably not doing much good. I'm considering swapping to an oil-to-water heat exchanger as that could give me a quicker oil warm up, especially in the winter when we see temps around 0-10 celsius. Not sure what control strategy I want though.

The real benefits would come from running a smaller radiator inlet, so the only way to get that without risk of overheating is efficient ducting and possibly greater water flow. Dumping heat in the cabin is something I want to avoid.

Reports that electric water pumps don't match engine driven pumps are discouraging. Maybe I'll have to run two pumps! For road use I'm only running to 3000 RPM on the highway, with higher bursts in the lower gears. The engine temperature rises when stuck in traffic, and the low water flow when the engine is idling must be an issue.

Can anyone point me at water pump flow-vs-rpm data?