electric fan and water pump controller

[64mali]

Does anyone know if there is a product that will controll the electric fan and water pump? I'm trying to loose the switches and make everything work automatically. I have a BBC with Mezierre water pump and electric fan. Plus I don't have enough ports to install a guage, fan, and pump thermostat seperatley.

[intocarss]

Is this a drag car?? As long as the eng is running, why wouldn't you want the WB on at all times?

[hotrod69camaro]

It would seem to me that you could take power from your fan realy and put it to your water pump so it comes on with your fan. You might need to use another relay for the pump due to the current draw. I would think you would run the pump all the time or it would heat up pretty quick.

[Bryce]

I would run the pump while the engine is running unless you need to save the extra horsepower draw from the altenator...

Also I would always run an overide switch to manually turn the pump and fan on to make sure the the car doesnt overheat incase the temp sensor malfunctions. I like to have the option to turn the pump and fan on while the engine is off to cool things if neccessary.

[GregWeld]

A thermostatic switch - same one that would switch your fan on - can run the relay that runs your pump. These just switch to GROUND.... so it's just making your relay "grounded" on the switch side. Run your heavy leads for your power supply --- and the positive (small wire) to ignition switch (+ when the car is running) and the negative to your thermostatic switch... and you're done. The ONE thermostatic switch can easily switch both relays (Fan and Pump). It's doing nothing but grounding out the relays (hardly any load).



If you're using a relay - make sure it's matched (amperage wise) to your pump. 30 amps should be fine but you'll have to see what your pump draws.


Your relay should be numbered

#30 is the positive (fused) from your power source...

#87 is the positive (fused) to your pump

#86 is the positive to your ignition

#85 is the NEGATIVE to your thermostatic switch

You pump should just be grounded to a good nearest possible point.

Make sure your power leads are capable of handling the load given the distance...

The #85 and #86 can be light duty since they will only carry very small amount of amperage. They're just switching the relay on or off.

[L n L]

I use a DC Controls controller. One unit that controls both the fan and the pump, with variable speed.

When the motor is cold, they both run at about 10% speed. I have a temp probe that connects to a bolt on the thermostat housing that send a heat signal to the controller, and the controller has an adjustment that I use to control the "100% speed" point. I have mine set to keep the motor at about 180 during mild driving. The controller varies the speeds of the pump/fan in a nice linear method, elminating the voltage spikes you get with on/off type controllers.

I took the car on the Hot Rod Power Tour last June. We drove 4,405 miles altogether. With over 300# of tools, spare parts and luggage in the back, and track temperatures around 106 degrees, I ran an 11.7 @ 117. Driving for hours straight at 80-85mph (GPS verified) in temps over 100 degrees, the motor got close to 210 a few times, but never over.

I also have an over-ride switch for the controller, so that I can turn the pump/fan on while the motor is shut off. That allows me to bring the motor from over 200 to 160 or so in just 3 minutes or so.

Lee

[64mali]

Thanks guys, very good info.