Cams AE85 build from NZ

[slacker.cam]

Here's a small update on the electric water pump saga. The background is that when I modified the 20V to have the pipes from the radiator enter at the front of the engine I decided it would be a cool idea to use an external electric water pump. I had previosuly used them extensively on our Formula SAE cars (http://www.fsae.co.nz) and I liked the idea beacuse:
- Reduced load on the engine (the elec pump is far more efficient than a mech pump)
- No need to make complicated water outlets or have complicated plumbing
- No need for a thermostat (saving weight and reducing complexity)
The idea was to remove the innards of the 20V water pump and weld a plate over the hole in the back where the water would normally enter and weld a new fitting on the front - this should give me tidier plumbing. I did this AGES ago (as documented above) but I've always been concerned by the idea of having no thermostat on the car.

This website has some great information on cooling options for 20V 4AGEs in RWD configuration: http://s-86.com/s-newcoolingguide.html

You can see from the website above that on the 20V motor the thermostat orignally lives in the block that bolts to the back of the motor. This is not used in my setup so I need a different solution. The other options were to run an external thermostat (ugly) or get a water pump from a RWD 4AGE (expensive). Hence the attraction of the electric pump.

A good friend of mine has always argued that the car should have a thermostat as it increases the pressure inside of the engine and helps to reduce localised boiling. Recently I have been thinking about this a lot as I don't want to risk damaging my motor. I now believe that this is a false statement (at least in the 4AGE world) as the thermostat on a 16V motor is at the start of the cooling flow and would therefore put the engine at a lower pressure than the radiator. The image below shows the flow direction:



In addition to this I also stumbled across the FAQ on the Davies Craig website. This has made me even more confident in not running a thermostat. This is an excerpt from the page:

What do I do with the engine’s existing thermostat?
If you choose to use the Davies Craig Digital Controller you should remove the engine’s thermostat – the Controller is the new “thermostat”. The Digital Controller allows you to electronically set the engine target temperature and it adjusts the rate of coolant flow, hunting for, and then locking onto the temperature you set. You have five (5) options; 70c, 75c, 80c, 85c and 90c for either economy or performance, unlike your thermostat, which is set at one temperature by the engine manufacturer.

More can be found here: http://www.daviescraig.com.au/Electric_W...ntent.aspx

So my thoughts are now far more positive and I think my solution will be very elegant. It will be ultra simple from a plumbing perspective and if the marketing material is correct then I stand to gain a lot from ditching the mechanical pump