Electric water pump

[rgathright]

From my experience with Chevy V8's, you must leave the electric water pump on in street cars. The risk of relay failure with aftermarket kits is just to great in engine compartments.

Additionally, a belt driven water pump is always spinning which helps circulate the water in your engine when the thermostat is closed. The problem is that the variable engine RPMs help circulate the water faster when the car is accelerating so you get better flow.

The other problem was that the Weiland electric water pumps sucked. They were cosmetic builds 10 years ago. The "water passages" inside the pumps were restrictive. We wanted to drill them out but then you void the warranty. Ugh..

The lesson's we learned were hard and involved the overheating of several race engines before we finally just gave up on electric water pumps in passenger vehicles. They work great for drag racing because you only run the vehicle for brief periods of time. In fact, we liked electric water pumps because they allow you to cool off the engine when it is turned OFF. That means you can get consistent ET's by maintaining engine temps avoiding the costly predetonation found as the engines get hotter.

[NiHaoMike]

Originally Posted by rgathright

From my experience with Chevy V8's, you must leave the electric water pump on in street cars. The risk of relay failure with aftermarket kits is just to great in engine compartments.

Use MOSFETs. They would fail shorted, which would leave the pump running at full speed.

[rgathright]

Originally Posted by NiHaoMike

Use MOSFETs. They would fail shorted, which would leave the pump running at full speed.

True!

An electric water pump controller would solve these problems! Just get a high volume water pump and restrict the voltage based on a temperature algorithm.

[smokeyj]

So to sum up if the details are wrong this is a bad mod?
Probably true about any mod.
The Davies Craig video claims they have spent years engineering their electric water pump to work well in a automotive application.

They also explain how they control the pump, at low temps the pump runs at a low duty cycle to just barely circulate the water, as the temps increase to the set point the ON/OFF duty cycle is increased. This means that the pump only runs as hard as it needs to in order to control the temp.

This level of electronics is not too hard in theory.

[Arragonis]

Slightly OT but PPC magazine here in the UK had a space problem under the bonnet of one of their vans, so they rigged up a mains powered central heating pump and fitted a voltage inverter to make it all work. No complicated electronics.

[smokeyj]

??? Voltage inverters are complicated in this setup you now have a triple conversion problem. Fuel to DC DC to AC AC to pumping.

But interesting point hot water circulation pumps might be a source of parts. They are certainly long lived and work with hot water. Issues might be weight and vibration resistance?

[basslover911]

I think the biggest part is the electronics... how about a simple circuit that gives it minimal voltage (i.e. flow) at anything below (lets say) 170 degrees. Then ups it to mid flow from 170-190 degrees. And max flow (again, i.e. voltage) at +200 degrees. Simple, 3 "step" pump.

Anyone know how to make a circuit like that?

[rgathright]

We will need the circuit to go on the "FULL ON" state in the event of thermocouple failure.

[mikeross]

Originally Posted by rgathright

An electric water pump controller would solve these problems!Just get a high volume water pump and restrict the voltage based on a temperature algorithm.

Really? That's a pretty good idea. Maybe I will try this out and see what happens. Thanks for the suggestion!

[bs0u0155]

I've been looking at the Davis Craig electric water pumps, and concluded they could be quite good for FE. Mainly for two reasons, 1. in many short journeys you'd be up to temperature faster. 2. you can modulate your whole engines running temp. I believe my car is thermostatically set to 85C. I believe that a higher temp, e.g. 90C gives better FE? also it allows radiators to work more efficiently as there's a greater delta t between them and the environment, which would allow for more aggressive grill blocking.

then there's the obvious advantage of removing another draggy belt pulley if your auxiliary drive belt path is amenable to removing one and fitting a shorter belt.