New Elite owner from Sweden!

[lahi]

If you do go for the DC EWP, consider using the 80. A forum member (Keiren) reckoned the EWP115 he used his on his new 2.5 litre tuned 912 engine, combined with an upgraded alloy radiator, resulted in thermal shock to the block/ liners. The ewp115 flowing a sudden large shot of cold water from the rad. That said, the devil is in the detail regarding programming used to control flow.
And in any case, I found the ewp80 run either with, or without, a controller (analogue), is well up to the job on the 912 SE. And it pulls only 7amps max rather than 10A, which means the sTD alternator easily copes with the load. Plus I've run the ewp80 with an upgraded alloy rad and the STD brass/copper cored rad with no ill effects. The later digital controller programming is superior to my analogue version so pretty sure you won't have issues with the ewp80.
Anyhow you have more experience than most so I expect you'll know how to set it up right regardless of EWP size .

Thanks for the info! That doesn't sound very pleasant. Did he run into problems due to the thermal shock? He didn't use a controller to reduce flow at low engine temp or perhaps that didn't help?

Do you control engine temp with the ewp on your car so you don't use a thermostat, or how does your analogue controller work? Have you run it without controller too earlier? How did that work out?

A lot of questions

I have quite some experience regarding engine cooling and engine design but there's always someting new to learn!

[Lotus-e-Clan]

I removed the belt driven impeller from the wp housing and blocked the hole with a compressible rubber bung - via through bolt and large penny washers each end of bung. Or you can alum weld the impeller shaft hole if you please. The rubber bung is reversible and reliable (since 2005 ish). Assuming the 907 housing is same as 912, you need to block the internal bypass passage too. I did this with epoxy - also reversible.
Ran ewp80 at full speed for 10 years without controller and with thermostat retained. Engine ran a bit too cool at 78c - 4c below normal stat temperature!

Now run with Davies Craig controller with no thermostat. Plus a full speed pump override switch on the dash just incase I feel the program needs help in traffic. Analogue controller no longer available. Davies Craig digital controller is the way to go. Engine runs at 82c with controller.

[Lotus-e-Clan]

BTW, The placement of the Davies Craig controller temperature sensor is fairly critical to cooling system homeostasis.

Ideally, the sensor should be placed within the combustion chamber water jacket because the controller program change is 'reactive' rather than 'pro-active'. You want the controller to increase coolant flow in immediate response to the temperature change of the coolant around the combustion chamber / liners. If you place the sensor in a more remote hose location, the slow speed 'maintenance flow' program will delay the hot combustion water jacket coolant reaching the remote temperature sensor in a timely manner. ie. the temperature delta between combustion chamber coolant and radiator coolant may become much greater than you want for proper coolant system homeostasis. A very large temperature delta could cause thermal shock to the block / liners.

My temperature sensor is located deep within a cylinder head hose tail outlet, thus poking directly into the water jacket around No 4 combustion chamber / cylinder.