EWB Location?

[Paul Proefrock]

Trying to sort out where to mount a remote water pump. I've searched the forums and there is some very helpful information but I am getting mixed inputs on whether the pump should be up front near the radiator or in the back by the engine.

Is this a preference thing or is there valid reasoning why one location is better than the other?

 

[H.J.Bayer]

I was told by Craig Davies and Pierburg to position the pump close to the radiator. The path on the suction side should be as short and cool as possible

 

[JP Verweij]

Usualy up front just after the radiator exit.

 

[Joel Heinke]

There's a very good thread that Howard started on EWP topic: https://www.gt40s.com/threads/electric-water-pump-how-to.57366/

 

[Howard Jones]

ALL coolant pumps for any application should discharge the coolest fluid in the recirculation system as directly as possible to the hottest location in the heat source. This takes advantage of the highest temperature differential in the system and therefore is the most efficient location.

What did I say? Attach the pump outlet to the engine coolant inlet directly or as close as possible.

This is basic thermodynamics. The higher the temperature differential between the hot inside surface of the head water jackets and the cooler temperature of the coolant, the higher the heat transfer rate into the coolant. There is also a flow rate difference at the pump outlet versus any point downstream from the pump impeller (the highest fluid pressure is at the pump impeller), such as after the coolant flows through 6-8 feet of pipe from the front of the car.

Adding a pump to the inlet of the radiator isn't a bad idea but it should be the second pump in a dual pump system. This is how many prototype race cars are designed. Two pumps effectively cut the system into two sections and maintain pressure in the system more efficiently.

The picture below shows the pump attached directly to the engine coolant manifold that replaces the mechanical pump in my SLC. The left side is the engine inlet, the curvy pipe is the return from the cold side of the radiator, and the AN fitting is the expansion tank inlet hose attachment point that goes to the bottom of the expansion tank.

 

[Paul Proefrock]

Do you see the confusion here?

I understand Howard's comments but also give credence to the other two opposing comments, especially the one with Craig-Davies and Pierburg notation.

I guess I am living up to my state's (Missouri) motto, Show Me. Howard, I keep re-reading your EWB post and searching Google. I guess I'm just too inquisitive.

Paul

 

[Fred W Ballinger]

Be aware that the pump manufacturers are used to dealing with questions on cars that have the engine in the front, adjacent to the radiator.

 

[Jean-Marc]

I have my second pump installed just after the radiator, but at this stage, I am still in the rebuilt phase, I cannot tell you if it is efficient or not.

 

[Howard Jones]

This came from Davies Craig. Watch this, then put the motor in the back of the car, leave the radiator in the front, remove the mechanical pump, and replace it with a manifold. Now you have the typical mid-engined prototype. Another consideration is with the pump as I suggest is that the water volume in the pipe that goes from the radiator down the side of the car to the pump inlet helps improve "head" but the other way makes it worse. All these little things add up. But at the end of the day, it's your car so you can do whatever you like.

 

[Bob Putnam]

On our installation, I was able to mount the D-C pump as the video showed. It was tight, but there was enough room between the engine's disabled pump and the water pipe that came out of the bulkhead.

 

[Howard Jones]

Jean, I was wondering how you are controlling the pumps? Do you run them both full-on all the time, one full-on and the other controlled by the DC electronic controller, or a different controller on each pump? Do you run a DC controller or another electronic controller type?

The WSC prototypes run their 2 electric water pumps, one in the front and one in the back, full on all the time. But then the car is making full power all the time.

Youre the first guy to do this that I know of on a self built car like ours. It will be interesting. As a data point for you. My SLC engine makes about 550HP and uses one Davies Craing 150 pump with their controller. It runs rock solid at the set temp all day on track in Texas on a 105F day. I do also have a lot of oil cooling and I bet that helps a lot.

 

[Jean-Marc]

Howard, The electric pump is controled by a switch that the pilote shall move when he estimate that the temperature is going to high, it is the comment of the previous owner and at this time, I did not experiment the engine. I add that my engine is a Dart 363 equiped with a mechanical water pump and that give 550 to 600hp.
I am not in favor of to much electronic control, especially on such car. May be you may drive the car in a initial period with a switch on the board and when you will know more on how the machine behave, you may add some electronic control.