I have a home built kit car with a Euro s50b32 engine fitted, I am trying to fit a Davis craig electric water pump and digital controller and I am having some issues.
The water pump controller instructions detail that the mechanical thermostat should be removed, I have done this and found a difference in operating temperatures between my dash gauge ( which has a sender located next to the stock water temp sender) and the Davies craig controller sensor which is located in the top radiator hose. The dash gauge is reading 110 degrees whilst the water pump sensor is maintaining its set point of 85.
I believe that removing the thermostat is now allowing coolant to simply flow through the stock mechanical pump inlet and straight through the stat housing and back into top of the radiator and not flowing through the block.
Has any one had any experience of fitting one of these types of pump in an m3? I think refitting the thermostat locked in the fully open position would force coolant to go though the correct route and still allow the digital controller to function correctly?
I had the same problem, and went through the same thought process. http://www.r3vlimited.com/board/show...&postcount=142
I got the car to last about 2 laps at COTA before the temps were very high. I spent two days down at the track fighting this thing before removing the pump and putting the stock pump back in and having the car run fine. While messing it with it one night a nice mechanic came over to check out what was going on. Turns out he had a customer with an S54 who wen't through the same circus act. A few minutes later and the S54 Mcoupe guy is on the phone with me explaining what he went through (what I was going through, and what you're describing.) and how he fixed it. His biggest fix was simplifying the coolant system.
In the stock coolant system routing, the expansion tank and the heater core return are in suction from the water pump. When you put the EWP in the lower radiator hose, that line that comes into the back of the water pump housing is now being pushed. He deleted the line off the back of the pump, removed the heater core (because racecar) had an aluminum radiator and added a bung to it so the expansion tank was now in suction from the EWP. He said once this happened the car stayed in range. I forget what he did with the t-stat, but I think he propped it permanently open, and I think he hardwired the pump to run 100%.
If you figure out how to make it work, post it here as I'd like to give this another shot but it's now pretty far down on my project list!
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