Ready for electric water pump now..

95Blitz

Well-Known Member
I have been planning an electric water pump for a while now and been wondering how to do it. Well this is my solution. I have stripped the factory water pump and installed brass freeze plugs where the shaft and seal went. So now I have a blank housing. My plan is to run a Davies Craig DC-8105 water pump up close to the radiator. With 35mm adapters for the pump. https://www.summitracing.com/parts/dcw-dc-8105

I'm going to install the balance shaft deletes at the same time.
Well what's the thoughts the group?
 

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Gtstorey

Goblin Guru
I haven’t researched it, but I would be interested in seeing the math. Same amount of water is same amount of work. I guess maybe it frees up hp when you really need it and recoup it when off throttle. But with electric it will be either pumping extra when rpm is low or pumping less rpm is high. Unless it has a controller tied to rpm.

With the failure rate on intercooler pumps, I’m not sure I would want electric water pump on a street car that is driven a lot.
 

95Blitz

Well-Known Member
Current draw will be less than the drag on the chain system. Plus I will be loosing the drag from the balance shafts with this. It wont be much 5-10HP max I would think. The problem with the intercooler pumps is the design of the motor and it's location on the car. I'm willing to bet the design of the Davies Craig motor is better than the intercooler pump motor.
 

jirwin

Goblin Guru
I imagine the delete itself doesn't free up too much horsepower, but being able to rev it higher probably will give you some decent gains depending on the setup. Plus, on this car 5hp is ~10-12hp in a normally weighted car. Little increases go further when its light.
 

Ross

Goblin Guru
You guys convinced me that I need one (DC8930) for my engine build. I am getting rid of the balance shafts, and adding this will eliminate the extra chain and sprockets. Might as well do it when the engine is open.

If you combine the Davies Craig coolant pump with the controller it can automatically run on for three minutes (or to 14°F / 10°C below the set temperature) after engine shut down, eliminating ‘heat soak’ and extending engine life and will cool a water cooled turbo too.
The controller can also eliminate the coolant thermostat and the water pipe that runs under the exhaust manifold.
 
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95Blitz

Well-Known Member
You guys convinced me that I need one (DC8930) for my engine build. I am getting rid of the balance shafts, and adding this will eliminate the extra chain and sprockets. Might as well do it when the engine is open.

If you combine the Davies Craig coolant pump with the controller it can automatically run on for three minutes (or to 14°F / 10°C below the set temperature) after engine shut down, eliminating ‘heat soak’ and extending engine life and will cool a water cooled turbo too.
The controller can also eliminate the coolant thermostat and the water pipe that runs under the exhaust manifold.
I was hoping on doing that with the fan circuit in HP tuners but I don't see a way to do it.
 

Ross

Goblin Guru
I was hoping on doing that with the fan circuit in HP tuners but I don't see a way to do it.
HP Tuners will allow you to program the Cooling Fan 1 based on the temperatures.

The Cobalt also has a spare sensor and 30 Amp fuse & relay circuit that could be repurposed.
HP Tuners will let you program the AC pressure sensor and Cooling Fan 2.
It doesn't know if the sensor is measuring AC pressure or some other 5V sensor, so you can just wire it to a new sensor, and Cooling Fan 2 can run a coolant pump instead.

The PCM/ECM will turn on the SER/PAR relay with the Cooling Fan 2 relay.
The fans on a stock Cobalt run on high (fans in PARallel, so 12V to each fan) or low (2 fan in SERies, so 6V each).
You might want to disable the SER/PAR relay circuit which is what the Goblin does, when it wires Cooling Fan 1 to ground, instead of running that white wire back to the SER/PAR relay.

The Davies Craig controller does more than just turn the coolant pump on and off. It will run it in low pulse mode when the temperatures are cold, then medium pulse mode, then full on.
 
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95Blitz

Well-Known Member
I was hoping you would answer on this Ross. Your saying the stock Cobalt fan control is off/6v/12v or off/low/high? Even though it shows in HPT % of fan desired. I trust that your correct 100%. I like your idea about using the A/C side of the fan system. Now to find the old A/C pressure switch so I can get the voltages at the different pressures. Found the switch but not even sure I need to do the test now... so confused..
 
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Ross

Goblin Guru
Yes the stock Cobalt fans (there are 2 on the front radiators) are on and off based on the temperatures set in the PCM tables.
HP Tuners makes it look like the fans are variable speed with the "% of fan desired" in the tables, but the PCM just uses these tables to turn on or off the relays, giving us off/low/high fan speeds. Or off/high speed if you don't use the SER/PAR relay, like the goblin is wired to do.

When Fan 1 is requested and Fan 2 is off, then the SER/PAR relay is off, and then both fans run at 6V. In the goblin Fan 1 would run at 12V.
When Fan 2 is requested then both the SER/PAR relay and the Cooling Fan 2 relays are energized, and Fan 2 goes to 12V.
When both Fan 1 and Fan 2 are requested, then all 3 relays are energized, and both fans run at 12V.

The voltages for the A/C pressure sensor (not a switch) don't really matter, as HP Tuners doesn't show us what the stock sensor voltages are. When you wire a new sensor to that circuit, then ECM will read the voltage , and convert it to a KPA (0-3000 Kpa range) and it will turn on and off the Fan 2 relay based upon the tables in HP Tuners.
You will have to calibrate your new sensor using the Kpa tables in HP Tuners.
(either the Fan State Transistion Desired vs Current State table
and/or the Fan Desired % vs AC Pressure table.)

Here is the 5V wiring for the AC pressure sensor. (HVAC Diagram 2)
It shows the AC Pressure sensor has a black 5V- wire, a grey 5V+ wire, and the returning sensor (0 to 5V) wire is red with a black stripe.
The sensor is located pretty close to the AC freon pump.
39160
 
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95Blitz

Well-Known Member
Yup, that's the way I thought you was explaining it. Well that won't really work the way I want,I want it to be variable speed. Thanks for the help Ross.
 
I designed it and had a local machine shop make a batch. It has a -10orb on the left and threaded for the temp sensor on the right. uses factory o-ring. I had put it in the "parts you wish df offered" thread a while ago. I got impatient and did it myself, lol

water block post
 
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