Electric water pumps

[Dezertpilot]

I was looking through my Summit mag and saw a universal electric water pump. It has a bracket that sits off the side of your motor and has a small motor and from the motor and then a belt to your water pump. It says that it frees up to 17 HP and I was kind of thinking about putting one of these on my 4runner. I have a 1987 7m-ge motor that is swapped in. I know I would call and ask Summit if it would fit my app but lets say it does. Is it worth it? Its under $180 and looks nice. I do know its one more electrical accessory but if I can gain 10 HP or more I think I would be happy. What are you guys thoughts on this?

[steveG]

I don't think its worth it. It's just one more thing to go wrong in the desert. Especially when the cooling system is concerned, simple and effective is the key. Besides that, most of the electric water pump drive kits are designed for short duration use like drag racing.

[TheWebWheeler]

Yeah do really want to have that be what bones you in the middle of no where?:eek:
I agree If your only drag racing or maybe running in a short corse at a track like ROR then it might be worth persuing But if your running out in the middle of nowhere I would'nt do it..http://www.thewebwheeler.com/forums/images/smilies/m2c.gif

[Josh_K]

I dont think those things will build enough block pressure to cool a car that is ran continuisly. I think there nitch is in 1/4 mile cars.

It is typical for a v8 race engine to run 30 to 40 psi in the block of pressure. This reduces the ability of the coolant to boil. This is how cars can run temps or 265 and not boils the coolant off.

BTW, I am sure you know this but when you take the thermastat out and run a disk in it place, the smaller the hole in the disk and cooler the engine will run. The reasons are two fold. 1 more block pressure. 2 the coolent crosses the rad slower and has a more time to exchange the heat to the air making cooler water.

Josh

[Ramsey_ElWardani]

Josh, if that were the case, why wouldn't it blow all the coolant out of a 18 -22lb radiator cap, being that it is a closed system and pressures equalize in the whole system?

[Stephen]

I almost hate get this started but I guess I have to.

Slowing the water down through the radiator will only hurt your heat rejection through that radiator. The higher the flow rate, the higher the heat rejection rate. Reason is that heat is transferred best at high temperature differences. If your water comes out at 260 and the air is 100, you have a 160 degree difference and heat will fly out of the water since the air is so much cooler. If your water is only 200, you reject less heat because there is a lower temp difference.
If you slow the flow rate down in the radiator, the water at the inlet will be our theoretical 260 and the water at the outlet may only be 200. The water at the outlet of the radiator will be rejecting heat slower because it's so cool.
If you speed up the flow rate, the water at the inlet will still be 260 but the water at the outlet could be 240. The higher outlet temp will reject more heat to the air before it heads back to the motor for another load of heat.

Don't get hung up in trying to control temperatures with this example or even in real life, you're really trying to reject HEAT. If you get rid of lots of heat, temps will take care of themselves. I know it seems intuitively obvious that you would be better off putting that slower moving 200 degree water in the motor but it's not.

This same idea is why running high coolant temps is good for cooling. If have 100 degree air and try to regulate the block to 160 degrees, you have to have a huge cooling system because you only have a 60 degree temp difference to reject heat with. If you run a 260 block temp with the same air, you reject the same amount of heat with a smaller radiator.

[Chris_Wilson]

"being that it is a closed system and pressures equalize in the whole system?"

Sounds like you are thinking of a static system, not a dynamic system.
When fluids are flowing, a restriction to flow will result in a pressure
differential across the restriction.

An analogy would be a voltage drop due to current flowing through a resistor
(or a wire which has some resistance). When the current stops flowing then the
voltage becomes the same on both sides of the resistor.

Likewise, there are restrictions to the flow of coolant in your system. Some are
insignificant, others not. The pressure before and after the water pump is not
equal (except when the pump stops pumping!)

Or I could be wrong...

[Dezertpilot]

Ya Im not going to do it but this kinda brings up an interesting topic.

[Josh_K]

Stephen..... I don’t even know what you said? I couldnt get past you second of third sentence.

Ramsey, wait a moment and I will get to you.

Chris, I think we are on the same page.

O.K. I will type slowly for the thinking impaired. Please don’t read too fast.

First one given, the higher the pressure on a liquid the high the temp will need to be to make the fluid boil. Example, water at an elevation higher than sea level boils at less temp than water at sea level. Furthermore, we have all heard that if an astronaut’s space suite pops a leak that his blood will boil. Well that happens because the pressure drops so low that it gets to the point that the blood in his body will boil at 98.6 f thus killing him/her just as water boils at a lower temp in the mountains than at the beach. So, as water or blood boils at a low temp/low pressure water (and blood) will boil at a higher temp and pressure that we are accustom too when the pressure is raise above that of atmospheric pressure.

Now back at it.

In a running engine Pascals law doesn’t apply because the restrictor plate adds a resistance to the system and builds a pressure on the fore side of it which happens to be in the block. As I have said a block can run a pressure of 40 psi but there will be less that 24 psi in the rad because it is on the aft side of the restriction.

For instance, if your 8 truck is really hot 250+, and you keep the rpm’s up (3,500+) the water wont boil out of it because all the pressure that is in the block fore side of the restrictor plate is raising the boiling point of the water in the block to a point higher that the temp of the coolant. Now it you shut the engine off and Pascals law become effective and the water will pop the cap on the radiator.

Now I am sure some one will argue with me and thats fine, just be aware that I know this works because I have experienced all this stuff for my self so you’re not going to change my mind!

Josh

[Josh_K]

Now Stephan, I have tried to read your post again and I still don’t get your point. Now please explain how my 909 logic is wrong.

If a coolant flow slowly across a radiator than it has more time to transfer it heat into the surrounding (ambient) air.

BTW, what ever you come back with will most likely be wrong because I know smaller holes in restrictor disks = cooler water temps. It’s as simple as that.

Now you are right about the closens of the temp spread being less efficaint but we not taking about normal temps here. I am talking about temp that will cause the water to boil in a block and warp heads.

Josh

Oh one more thing, please don’t come back with, “if smaller is better than block the flow off”.

[Stephen]

I think you're wanting to make a mess about 2 different things.

You're right about the pressure in the block keeping the water liquid, that's the reason we run antifreeze or other additives, they raise the boiling point. Liquid is way better than steam at picking up heat.

I'm saying you don't want to get into the mindset that slowing the flow of anything will aid heat transfer. The higher the flow rate, the faster the heat rejection.

To integrate what you're saying and what I'm saying, you should run a high flow water pump and then you could put a bigger hole in the restricter plate. This would retain your block pressure and increase the flow rate through the system.

[Josh_K]

I'm saying you don't want to get into the mindset that slowing the flow of anything will aid heat transfer. The higher the flow rate, the faster the heat rejection.

I dont think that I am. I am only saying what I know to work with American v8 engines.



To integrate what you're saying and what I'm saying, you should run a high flow water pump and then you could put a bigger hole in the restricter plate. This would retain your block pressure and increase the flow rate through the system.

OK, now I wont argue with that.

Josh

[Chris_Wilson]

Josh says: "Chris, I think we are on the same page."

Regarding pressure changes yes. But regarding heat transfer no.

Stephen says: "The higher the flow rate, the faster the heat rejection."

I believe the physics behind this statement is sound. Think of it this way:
If you have water running over a hot surface heat will transfer from the
surface to the water. The bigger the temperature differential, the more
heat is transferred per second. (Do you agree with this assumption?)
So the cooler the water, the more btu's you can extract. Think of the
flow rate as the speed at which the water heated by this heat transfer is
replaced with fresh cooler water and I think you will conclude the higher
flow will remove heat faster.

In theory at least. In the real world, the conditions under which a theory
holds true are often not present. There are limits to how fast you can
make the flow before you create some other problem that screws up the
theory of "faster is better".

I think one way people get lost in the analysis of cooling systems is when
they remove the thermostat which removes a restriction and increases flow.
Yet the water temp goes up. So they conclude faster flow is bad. If you
look deeper, I think you will find you have changed something else (unintended
consequence?)

When you increase flow by reducing the restriction of the thermostat then
you have also reduced the pressure differential across that thermostat and
reduced the pressure in the whole system (dynamics only - i.e. only during flow.)
If you reduce the pressure enough, you will enable the pump to cavitate and
create air pockets in the heads. Bad for heat transfer.

Same idea holds true for the propeller on a boat or the shock oil behind a
moving shock piston. There is a low pressure created behind the piston
or the prop in the water pump. If the absolute pressure of this low pressure
is low enough then the fluid will outgas (boil). In a shock we prevent this by
using a pressurized system. Ditto in an engine cooling system, the pressure
prevents cavitation behind the pump impeller.

If you are still reading this, two comments. 1) get off the internet and go prep
your racecar!, 2) back to the topic of electric water pumps, just make sure
they are designed for endurance racing and not drag racing. And that's my
two cents...

[TheWebWheeler]

OK for the sake of aguement http://bestsmileys.com/argue/1.gif What about not running any thing at all in your Thermostats housing?
just allowing free flow..http://www.thewebwheeler.com/forums/images/smilies/shrug.gif

[Josh_K]

Read Chris's post again. The answer is in there.

[Josh_K]

OK I wont challange any thing that you just said.

But the bottom line is what I am saying is still correct in the world that we race these trucks in. But I think you are technically correct.

I will now put my front teath back in and start breathing some more of that fresh 909 air in my shop.

BTW the point about the out gassing of the air around the impeller shaft is good. I hadnt thought of it that way.

[ntsqd]

Josh, do you use one of those flat disc restrictors, or a venturi type restrictor? We had Steve Jennings (IRL engines, etc.) insist on a venturi type for a BMW 2 liter he freshened up for a road racer. His reason was that the flat disc induces turbulent flow which leads to cavitation at high flow volumes.

As to the electric H2O pumps, I know that there are marine application electric cooling pumps. I know nothing about them. I'd be more inclined to use a belt driven pump made by a pump mfg in place of a 'stock' type belt driven pump.

[FABRICATOR]

These guys know cooling systems pretty darn well and have a good tech-tip section:
http://www.stewartcomponents.com/Tech_Tips.htm

They make an inline electric water pump with a 10,000 hour life expectancy, but it is
still only aimed at drag racing.
http://www.stewartcomponents.net/Merchant2/merchant.mvc?Screen=PROD&Product_Code=E558A&Category_Code=ElectPump

Don't forget that air movement is just as important as fluid movement.

[Stephen]

Yeah, you really don't want to slow the air down.
I wondered about the stewart elec. pump. I thought it might make a nice booster pump for a remote radiator system but once again in the interest of simplicity, a high flow belt driven pump is probably your best bet.

[Josh_K]

Tom I am using a the flat plate style with a bone stock water pump and Rad is behind the cab. I have a really big Rad but the truck runs really cool. In the winter I move to the next hole size up because when it is about 40F out, it wont warm up with the smallest hole disk.

Josh

[ntsqd]

OK, just wondering if there's something to be found by going to the other type of restrictor. I would expect that possibly you'd get the same restriction with less pumping loss due to less cavitation, but even if that is true, it may not be enough to matter.

[klaus]

How about the meziere brand of electric water pumps? I se ethem in various car magazine ads.

http://www.meziere.com/index.php?pgName=wp111

Also don't have some newer OEM motors electric water pumps?

[Josh_K]

Dont know nuthin about them

[partybarge_pilot]

The last Barge had a Meziere pump on it for about 2 yr's. Worked great, had it on a thermostatic switch so the engine would reach temp really quick. Never had any problems with it. It will be going on the next project as well.

[hoeker]

i successfully ran 2 of those stewart in-line pumps on my CORR truck for a while, i went away from it because my alt. couldn't keep up and at 10v they just quit pumping(as opposed to pumping slow) the risk was too great to justify the benefits.

[TheWebWheeler]

Ok it seems most agree thats best for a drag race car..
Does any body know of a guy in any class DEZ Racing with one?http://www.thewebwheeler.com/forums/images/smilies/humm_smilie.gif

[FABRICATOR]

Guess not.

One of these days we will see higher voltage systems for racing. 12 volt systems are fairly beastly. We use way more electrical power than any standard street car, yet they are going to higher voltage soon. The OEM's are trying to decide between 36 or 42 volts.http://www.race-dezert.com/forum/images/icons/icon3.gif

[Outcast]

With regards to the system that was originally mentioned with the motor and pulley running to the existing water pump, those systems are definitely drag race only. In fact they typically aren't even ran while the vehicle is operating during a run. They are ran after in conjunction with electric fans, usually between rounds while the vehicle is on the charger. Those motors with those kits don't spin fast enough to provide the flow rates necessary for prolonged engine running and cooling.

There are some systems out there that are designated as actual "street use" pumps, however, I would strongly recommend discussing your particular application and intended use with the manufacturer before investing in one.

To be honest, for prolonged engine use (rather than short run use, like drag racing) I don't know that converting to an electric water pump would actually save that much over your stock belt driven water pump. You wouldn't be driving the actual pump with the engine, but you still have to run an alternator (something alot of purpose built drag cars don't run) and so the additional load placed on the alternator would then make it draw more power from the engine and thus you are back to using the engine's power that you were trying to save in the first place. Maybe slightly less power than what was being used to turn the pump but then you have to ask if that small amount is worth the effort to modify and also the subsequent reliability factors. Food for thought.

[FABRICATOR]

Transmitting energy through a belt drive to turn an alternator that turns an electric motor (even with a direct motor mounted fan) cannot be more efficient than a simple belt driven pump. On top of that, there is no way the electric pump would be going the right speed all the time. Maybe that's why no matter how great the pump is or how reliable it is, they are still only for drag racing. Funny, but a belt drive pump knows exactly what to do.

The fan is the thing that could use some tweaking and the OEM's have known this all along.

With or without an electric pump, we could still use a higher voltage system.

[ntsqd]

Would not surprise me to see the OE's go to electric pumps, in fact electric everything in the near future. The trend is going away from engine ("prime mover" in current OE terminology) driven anything. The idea is to let the prime mover do only that, move the vehicle. Batteries and APU/EPC's will take care of the accessories. Once that really starts to take hold is when to expect to see higher operating voltages.

[firedog]

The Radical SR3 race cars that we have out at the track I work at use the electric water pump. They are used in conjunction with a 1500cc suzuki hayabusa motor tweeked by power tec, as long as the car is moving (air flow) we haven't had any overheating issues.
Paul

[partybarge_pilot]

"On top of that, there is no way the electric pump would be going the right speed all the time."

You haven't seen these I take it? http://www.dccontrol.com/techwrk.htm

[FABRICATOR]

Nifty, but they are for fans, not water pumps.

Talk about hype for a product…
"This is important due to the fact that, psycho-acoustically, a change in sound level is more noticeable than a constant level, so that even at near full airflow, a variable speed controlled fan is far less audibly noticeable than a relay based system."

Isn't this the same thing as: "You won't hear the fan going on and off."?

[partybarge_pilot]

Thermostatic control of an electric motor. Works the same, They sell them for both.