Thread: Electric water pumps?

I was looking at this option some time ago when a site called auto speed were doing some testing.

Long and short of it was that Auto speed never published the articles and indicated that the threat of litigation from the supplier was not worth the risk to them being a small on line mag mag?

I think some of the advantages that were claimed included e.g. better performance, better fuel efficiency and better heat efficiency


Would be interested as well if anyone has info

I would suspect that the efficiency gains might top out at 1% or so, as you need to drive the electric pump via power from the alternator which is inherently less efficient than a modern belt drive.

I can see the application for 1/4 mile drags where the pump is driven for that time off the vehicle battery.

A Prius/hybrid might benefit from an EWP.

As for reliability, the best application for these might be Toy land cruisers as no-one cares much if they seize.

As said, short use drag apps or for a stationary application would be fine. A well set up standard system in good condition will win hands down. Not to mention the re-routing and replacement (and need to ID and find the correct) hoses to suit wherever you plan to fit it which in these days there usually isn't much spare room.

We tried one on a track car and it went into the bin.

i replaced a cam driven water pump on an vintage european car I restored with a craig davies electric water pump. ran it for years without any problems at all. wired it ti thermo switch for operation along with an overide switch for stiiting in traffic etc.

Had them on My Holden/Chev drag motors , a complete WOFTAM.
Only good for that trick look , along with Gilmer Drive ,Only for Trailer Queens!!

Been using 1 on a s111 to help the heater got it from davies craig webb site

Electric Water Pumps

they dont push as much water as a belt driven one DC say they dont need to?

What's their basis for that?

Will try and find the page on their site but here is one of the papers they refer to

http://www.daviescraig.com.au/Images...013Nov2004.pdf

and from their FAQ about water pumps

Question No. 13
Why is the power used by the EWP® much less than the mechanical pump?
The EWP® is designed for maximum efficiency at its maximum speed of 2250 rpm. Being in nylon, the impeller can have aerofoil cross section which gives lift and the tip clearances can be very small. The mechanical pump has to run at 600 rpm and 6,000 rpm and it cannot be efficient at both those speeds and all speeds in between. Furthermore, as the power the pump takes increases as the cube of the speed - when the mechanical pump is operating at the higher speeds, as it does as a car passes through its gears; it is taking power of the order of 6 to 10 kW. The EWP® uses at maximum speed, which is usually less than 20% of total motoring time, 9 amps x 13 volts gives 120 watts at say 30% efficiency from the alternator to hydraulic power means about 0.4 kW to drive the EWP®. The EWP® never needs to run at very high speeds where the mechanical pump is consuming high power and torque. In addition, with the old mechanical pump and a thermostat set up, the thermostat is partly closed most of the motoring time and in a cool climate at highway cruising, it is about 90% closed. As a consequence, the flow and pressure being generated by the mechanical belt driven pump and paid for with power and torque, are choked at the thermostat and wasted. This system has worked reasonably well for a long time but it is not smart. With your EWP and digital Controller, power and torque is never wasted as there is no choking (no thermostat) and only as much flow and pressure as is required is produced. We are starting to see the allowance of EWP® s in racing mostly for the extra power but also to prolong the life of engines with the run on after hot shut down to eliminate heat soak. In any case we cannot stop progress, nobody in racing runs drum brakes or cross ply tyres these days!!

sounds good dont know if it is all true seems to help my heater work a bit better anyway thats what I was looking for