Anyone using an electric water pump?

[Sledge]

On warm and hot days (85 deg F and above) I see water temps of 195 to 210 deg F, using a slightly larger (M3) than stock radiator and a belt driven Edelbrock water pump, even with my BMF Spal electric fan on. So, I was wondering if an electric pump, with a more constant flow, would be helpful. I'm using about 30% anti-freeze, 1 bottle of Water Wetter, and the rest is distilled water. 99.9% driven on the street in sunny SoCal. Lots of stop and go.

Brand, flow rate, etc recommendations appreciated.

Thanks

[mln385]

195 to 210 are good running temperatures why do you want cooler? Your motor needs to run in that area for proper operation and oil temps.

[Gaz64]

I would think you need a more efficient radiator.

Faster coolant flow is not going to help.

I don't like anything over 195F either.

Gary

[jhv48]

Does your radiator have a full shroud and an efficient puller fan?

[Sledge]

Thanks for the replies. The radiator is already larger than the standard radiator, which is supposed to be more than adequate for a 351W. The radiator is fully shrouded and has a Big Mother F______ Spal fan.

A mechanical pump is dependent on rpm for coolant flow. So, low RPM operation would mean lower water flow than at cruise. Thus, more flow at low RPM, as when driving around town, would seem to be beneficial.

[Dwight]

what is the CFM rating of your fan?

Coach installed a 2700 CFM fan and dropped the temperature a lot.

[scottj]

Originally Posted by Sledge

Thanks for the replies. The radiator is already larger than the standard radiator, which is supposed to be more than adequate for a 351W. The radiator is fully shrouded and has a Big Mother F______ Spal fan.

A mechanical pump is dependent on rpm for coolant flow. So, low RPM operation would mean lower water flow than at cruise. Thus, more flow at low RPM, as when driving around town, would seem to be beneficial.

If I was having a problem with low speed cooling I would add a Stewart Components electric booster pump and keep the mechanical pump.

https://www.stewartcomponents.com/in...&product_id=69

[eschaider]

Bill,

Your idea about the electric pump and more flow at lower speeds is pretty close to the mark.

I went to a Meziere electric and had some folks in Texas at Hollister Road Co. Make up a pump and fan management gizmo. They call it a Pulse Width Modulated Fan and Water Pump Control Unit <=clickable.

You can read the whole smash on their site but this is the gist of how it works. When you start the car only the water pump comes on at less than full blast. It's job is to circulate the coolant so no hot spots develop on warm up. As engine temperature comes up the fan(s) come on and both the fan(s) and water pump seamlessly vary their speed up and down under the control of the gizmo to maintain a target engine temperature you set.

At highway speeds if the fans are not needed they are turned down or shut off. When you park the car the fan and water pump run on for a minute or so to help the engine during cool down. The system uses no t-stat at all. Instead there is a temp sensor in the return hose to the radiator that the gizmo uses to measure engine coolant temperature and decide what the fan and water pump should be doing. It is a very nice closed loop system that works extraordinarily well.


Ed

[Jaydee]

I was told by my radiator guy that if the flow is to fast , then the coolant doesn't get a change to cool down, because it goes through the radiator to fast. So the thermostat serves as a restricter as well as regulating the temp.
JD

[scottj]

Originally Posted by Jaydee

I was told by my radiator guy that if the flow is to fast , then the coolant doesn't get a change to cool down, because it goes through the radiator to fast. So the thermostat serves as a restricter as well as regulating the temp.
JD

Yet no one ever recommends slowing down airflow through the radiator to give the air more time to absorb the heat... hmmm, strange.

[bobcowan]

Originally Posted by Jaydee

I was told by my radiator guy that if the flow is to fast , then the coolant doesn't get a change to cool down, because it goes through the radiator to fast. So the thermostat serves as a restricter as well as regulating the temp.
JD

This is true. For anything other than drag racing or autocross, never remove the thermostat and leave an open port.

Originally Posted by scottj

Yet no one ever recommends slowing down airflow through the radiator to give the air more time to absorb the heat... hmmm, strange.

You restrict water flow, not air flow.

[Jaydee]

I guess if you ran some boiling water over a piece of cold steel quickly it will still be hot, but if you ran it very slowly, it will get a chance to cool down. But if you cool down the steel with fast air it will just simple keep the steel cooler.

So how many drag cars don't use radiators? Top fuel rail don't seem to have a radiator?
JD

[jeffnolan]

Air is a poor conductor of heat, only the first layer of air touching the radiator fins has a cooling effect, the surrounding air doesn't get much tansfered to it. Convection by continuously replacing the contacting layer with fresh air increases the heat transfer to the bulk of the air in the vicinity of the radiator by conduction. Slowing down the air flow through the radiator quickly saturates the contacting layer of air to no effect on the surrounding layer, which is why no one recommends it.

Originally Posted by scottj

Yet no one ever recommends slowing down airflow through the radiator to give the air more time to absorb the heat... hmmm, strange.

[scottj]

Originally Posted by jeffnolan

Air is a poor conductor of heat, only the first layer of air touching the radiator fins has a cooling effect, the surrounding air doesn't get much tansfered to it. Convection by continuously replacing the contacting layer with fresh air increases the heat transfer to the bulk of the air in the vicinity of the radiator by conduction. Slowing down the air flow through the radiator quickly saturates the contacting layer of air to no effect on the surrounding layer, which is why no one recommends it.

Yes, I understand. The post you quoted was actually meant to be sarcasm. What most fail to understand is that the same applies to both air and water flow with regard to flow rate.

[monster7]

Originally Posted by Jaydee

I was told by my radiator guy that if the flow is to fast , then the coolant doesn't get a change to cool down, because it goes through the radiator to fast. So the thermostat serves as a restricter as well as regulating the temp.
JD

This is correct from a physical point of view, also true for water (heat transfer rate)! If the flow is too high, the heat transfer rate will decrease, also the efficiency will do so.

[cycleguy55]

Originally Posted by Jaydee

I was told by my radiator guy that if the flow is to fast , then the coolant doesn't get a change to cool down, because it goes through the radiator to fast. So the thermostat serves as a restricter as well as regulating the temp.
JD

Your radiator guy is giving you bad advice, probably based upon advice he got from someone who didn't know better. As scottj pointed out in post #22: "The longer coolant is in the radiator, the longer it's in the block gaining heat." That's almost a direct quote from what Stewart Components includes in their cooling Tech Tip #3. Stewart Components

More content from the same Tech Tip:

• "We strongly recommend NEVER using a restrictor; they decrease coolant flow and ultimately inhibit cooling."
• "Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures."
• "Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would over come the
  radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations
  were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool."

[jimbo01]

I tried an electric pump on my blown small block in my hot rod. I was never able to get the flow rate in order to cool the engine correctly. After trying all combinations of restrictors I gave up. Installed a aluminum stock pump and solved my problem Seems as electric
pumps are good for 1/4 mile drag cars.

[Jaydee]

Not many top fuel drag cars even use a cooling system. I've always been amazed by this. I guess the run is so short it wouldn't have time to overheat?
JD

[lippy]

Keep in mind when an electric pump fails, it's usually sudden and without warning. A belt driven pump will usually start to leak so you know to replace it.

[Jus Cruisin]

A lot of drag cars use blocks with no water jackets. So no radiator. No water jackets mean stronger block. When you see a car towed to the staging lanes and then towed back to the pits, it usually doesn't have a radiator or one that looks like a trans cooler.