Electric water pump effect on warm up times

[NachtRitter]

Seems pricey for what sounds like a minimal gain... $200 for PWM and $300 - $400 for a good electric pump?

[autoteach]

A forum member of another forum I belong to picked up about 10% on his motorcycle.

[Daox]

So, just to be clear here (since we've gotten a little off track). We're agreeing that there is no benefit to warm up times with an electric pump.

[dcb]

Originally Posted by mechman600

Nope. When the thermostat is closed, a bypass is open.

I've never seen a cooling system schematic with such a bypass, do you have a link to an image or something? I've seen tiny pinholes in thermostats to allow a tiny bit of flow.

EDIT: yah, i see it now.
http://www.innerauto.com/Automotive_...ooling_System/
so the bypass is always flowing through the engine, it just flows less when the thermostat is open. My misconception

Originally Posted by Frank Lee

Try running a box fan, then throw something against it that blocks the air...

Interesting observcation. Do you think it would it be fair if power were measured by a kill-a-watt? I'll have to try that when I get home, both in cavitation and dead-head mode (lay it in the floor).

[RobertSmalls]

Originally Posted by Daox

So, just to be clear here (since we've gotten a little off track). We're agreeing that there is no benefit to warm up times with an electric pump.

Yeah, the benefit would be minuscule at best.

[abently]

I agree with the logic, I think the only way one can sensibly reduce warm up times considerably, would be to reduce the amount of water in the system.

I.e. tiny radiator.

[tjts1]

One thing you need to keep in mind is the water pump does more than just move coolant between the engine and the radiator. As the engine warms up and the thermostat is still closed, the water pump is circulating coolant between the block and head to keep an even temperature across the whole engine. Your electric water pump would have to run at all times even when the engine is cold.

[mechman600]

Originally Posted by Old Mechanic

Early model T Fords used a thermosiphon system with no water pump.

So did early John Deere tractors. No pump at all....thermostatic control came through the magic of physics. The hotter the water got in the engine, the more thermosiphoning would occur, and thus, more flow through the radiator. The only control you had was the crank that operated the rad shutters to adjust airflow through the rad. In order for this principle to work in a modern engine, you would need a HUGE rad with HUGE pipes. Modern cooling systems develop 40+ psi of pressure at redline - imagine the amount of flow that that equates to. The aforementioned model Ts and John Deeres had only 30 HP and radiators bigger than a Kenworth's. As far as economic savings go, I don't know. Us ecomodders are always trying the keep the revs low, where our water pumps aren't really doing a whole bunch anyway. Drag racers (aka high revvers) use electric pumps, but we're not drag racers.

[Piwoslaw]

Originally Posted by tjts1

One thing you need to keep in mind is the water pump does more than just move coolant between the engine and the radiator. As the engine warms up and the thermostat is still closed, the water pump is circulating coolant between the block and head to keep an even temperature across the whole engine. Your electric water pump would have to run at all times even when the engine is cold.

I'll add that the thermostat has a tiny hole (or is never completely closed) to allow a small amount of coolant to circulate through it, instead of sitting in stagnant coolant. This is how it knows when to open.

[euromodder]

Originally Posted by mechman600

So did early John Deere tractors. No pump at all....thermostatic control came through the magic of physics. The hotter the water got in the engine, the more thermosiphoning would occur, and thus, more flow through the radiator.

At work we've got distillation columns working on the thermosiphon principle.

It's a bit more complicated to get them going, but there's no issues with leaks, no worn out rotors, and no additional power is used to drive circulation.