Qingdao

iTrader: (3)

Is anyone running an electric water pump?

I'm looking to go down this road, but any advice is appreciated.

What is your setup? What are your experiences? etc...

FDAUTO

iTrader: (4)

what car and for what application

j9fd3s

iTrader: (3)

lots of OE cars use them, the Germans have been using them as auxiliary pump$ for a couple decade$ now
there are some advantages and some not advantages.

the big advantage of an electric pump, is that you can mount it down low where the water is. the stock Mazda pump is up high where the air is, which is why these engines are picky about having air in the system.
the second plus to the electric pump is that, since you can drive the pump at the optimal speed, there is no high rpm cavitation anymore.
third, packaging is probably more flexible with the electric pump.

the disadvantages of the electric pump are that you need to buy a bunch of stuff, pump, controller/ecu
and then have enough electricity to drive it, so alternator etc
reliability is less well known than the stock pump. plus the stock pump fails by leaking, usually, and an electric pump stops working, so if it went its more catastrophic

weight could go either way.

Qingdao

iTrader: (3)

Porsche boxster. Mostly just daily driving use.




I guess I was asking if anybody knew brands to stay away from.


I'm running a 90 amp GM alternator, and not much else on the electrical system on this car, so I'll have the juice. I've seen a lot of EWP's using 24VDC systems. The 12Volt systems run 30 amps.

"Not working" Thats the part that scares me. I am hesitant to use one of those computer controlled systems. The caveman in me wants to get a thermo switch for 130-150 degrees and have it set up to run 7 volts and another thermo switch to run 14 volts at 190-210 degrees. More wires but less computer. Obviously I'd run a toggle switch to command the full battery voltage if I want.




I do like the ability to run the pump after I shut the car off. For a while I ran an extra aux pump on my other boxster and had it set up to a turbo timer. It ran for a minute after shutdown. Or I would turn it on in traffic to get some extra cooling (It had an isolated small radiator).

TeamRX8

iTrader: (2)

most people don’t seem to understand that you can have both

the ewp doesn’t have to run continuously in that scenario, but only when there’s a need for it to run.

it shifts some of the advantages and disadvantages around, but if one or the other fails it’s not an SOL moment. Having a backup is always an added complication though.
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Qingdao

iTrader: (3)

For me the benefit is the less restrictive cooling system. I'm having to pump coolant from the middle of the car to the front. I don't think the stock WP is up to the task especially when it has a thermostat in the way.

The electric water pump has this advantage; without a thermostat the electric water pump can just shut off and spin up when the engine temps need cooling.

Also, I can size up a bigger EWP if a regular sized EWP can't cut the mustard.


All this said I thought the stock Chevy water pump couldn't handle the load, and it has proven me wrong.


I think I'm gonna give the EWP a shot. Just the Summit racing one with a pair of thermo switches, and one thermo switch for the fan. I like the cave man simplicity rather than having some mystery box computer controlling my cooling.

peejay

I wouldn't shut the EWP off, and it kind of needs the restriction of a thermostat or restrictor orifice to promote internal block pressure. Even at "normal" coolant temps, the metal around the spark plugs can get up to 400F, you need a pump generating a few dozen PSI to prevent localized boiling. This is especially bad in a rotary, since the metal around the plugs expands inwards, which lifts the apex seals off and also puts a beaming stress on them.

You can tell when an engine's not running enough internal water pressure because the rotor housings look like garbage in short order.

Qingdao

iTrader: (3)

I've heard other smart people tell me this in the past about thermostats. I just figured the EWP kinda solved it by regulating the temperature. The EWP would almost act like a thermostat being a stoppage of water flow.


Some of the fancy EWPs I've seen have a variable voltage motor that slows and speeds up water flow depending on engine temp... Isn't that kinda what a thermostat does? Granted my "redneck" thermo switch idea doesn't do that, but the variable voltage most certainly would.



EDIT: Now I think about it, one of my issues with my idea of the multiple thermo switches is constantly turning an electric motor on and off. On and off is not good for electric motors.

I think I'm going to make a housing for a traditional thermostat, and just run the EWP all the time off a toggle switch (the car won't have a key ignition). Keeps wiring simple and should give the water in the jacket enough time to do its job removing heat from the engine.

peejay

If you stop water flow, pressure drops to zero.

This is one of the effects seen in high RPM rotaries that do not have underdriven water pumps. The pump cavitates at high RPM and this leads to pressure drop-off, which leads to localized boiling. It's also hell on belt life.

You need pressure for effective cooling and this pressure comes from the water pump. I have not paid close attention to the BMW electric pumps but my gut feeling is that they operate the pump speed based on boost pressure.

It's important to note that the thermostat in practically all engines does not stop flow, it merely keeps it from going through the radiator. The coolant is still always moving. They only entirely stop flow in very old, low specific output engines, where you almost don't even need a water pump. I have driven engines like this that cooled entirely by thermosiphon.

neit_jnf

iTrader: (17)

Waterless (Evans or diy) doesn't boil and can be run with no pressure. Plenty of discussion already.

Been running no pressure waterless for nearly 20 yrs in all my family's cars, starting with the FD

peejay

Evans has a boiling point below the temperature of some of the metal in the engine. It can still boil, albeit not as bad.

Evans says you can run no radiator cap pressure but this is different from block pressure. I have measured over 200psi of water pressure in an engine with the radiator cap off. The water pump pumps water, after all

TeamRX8

iTrader: (2)

Your typical Mazda wankel OEM pump impeller is never going to create significant pressure. 200 psig is getting into positive displacement pump-head territory.

For an orifice plate, take a t-stat and gut the centerpiece valve portion; voila … pretty much straight out of the Mazda competition rotary engine tech manual.

However, you also need to block off the bypass warmup passage. Typically tapping and using a 1/2” NPT plug.
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