Hi Tom. I like the idea of the spall controller and think I will order one from you.......What I have now is the b-cool (sorry) with duel spalls and they work really well except the are both either on high or off. The sensors used are....the original one for the gage which I moved to the right of the thermostat by drilling and tapping a hole for it. It wouldn't fit the fast burn head. We put the sensor that came with the fans, which is just a switch I think, in the head. The fans came with two relays and we added another so one fan would always be on with the AC. How much is the control with the variable speed and can you provide me with installation instructions?

 

No problem! Order this controller. You need to keep one of the relay harnesses installed. The controller wires to the primary fan and the harness for the secondary fan.




Link to controller

 

Had same problem. Tried green wire to guage with white wire grounded, messed up my guage reading. Since there is a 20 degree difference between off and on, I set the low setting to turn on at 20 degrees above operating temp (180) at 200 degrees. Now it shuts off at 180. High setting at 220, now shuts off at 200. Now it works fine.

 

I'm preparing to install this set-up in a few weeks. Did most of you wire the fans directly to the alternator (rather than the battery). Also, where is the best place to connect the orange wires that go to ignition?

Thanks!

 

To do it correctly, you should go to http://www.madelectrical.com/electri...evymain2.shtml and follow their recommendations.

Here are a couple of pictures - everything works quite nicely!



and

 

Excellent info and pictures - thanks!

 

Here is the lastest overview and guide lines from SPAL:

Note that the intent is actually NEVER shut the fans totally off!

Goals of SPAL FAN-PWM project:
1-decrease fan noise
2-increase fan life
3-eliminate need for additional sensor
4-give user ability to program ON temperature
5-A/C over ride capability
6-price at the cost of two relay harnesses

Intended operation:
The concept behind the FAN-PWM was simple; make a modern electric fan replicate an
engine driven-clutch style fan. The old clutch style fans were spinning all the time, but they
weren’t fully engaged until a specified temperature was reached. This removed the strain
on the engine, while allowing adequate cooling when required.
By allowing the fan speed to change based on engine temperature, you allow the cooling
system to determine how much airflow is required to keep the engine within normal operating
temperatures. In most applications this means the cooling system can be kept at a stable
operating temperature with the fan running at only 80% of full capacity. If the engine
temperature increases, most likely due to towing or low speed cruising, the fan will increase
in speed to maintain a normal operating temperature.
Because the FAN-PWM was designed to alter the speed of the fan, SPAL USA suggests setting
the High above the thermostat rating, and setting the low at least 20 degrees below the
High. (SPAL USA suggests setting the high 10° to 15° above your thermostat rating). This
allows a broad range for the fan to vary in speed, while providing some insurance should
the cooling system temperature rise above the thermostat rating.
By programming your controller in this way, you not only have the advantage of automated
fan control, but the fan will also be turned off, or spinning very slowly, when the vehicle is
traveling at speed on the highway. Though the fan may be running at 50%, this does not
overly restrict the air moving through the radiator core.

In this excerpt from our new (not yet released) instruction booklet you will notice that we want the fans to run almost all the time.

This increases fan life. The motor brushes take the most abuse when the power is turned on and off at full 12VDC (or even worse, 14.4V when the alternator is running). By using Pulse Width Modulation we increase the brush life by not abusing them. As you know, our High Performance fan line already has an expected motor life of 10,000 hours (that's over 416 straight days. If you ran the car 8 hours a day, 5 days a week, the fan would last 5 years. That equates to over 300,000 miles at 30 miles per hour average speed). Needless to say, we don't mind having the fans run.

Wiring:
When using any sensor already connected to a circuit in the car (coolant temp sensor, oem gauge sender, aftermarket gauge sensor), you MUST use the white wire. You SHOULD NOT use the green wire unless you are using the SPAL sensor. The PWM supplies a small current on the green wire, and reads the change in voltage on that wire. If you connect our green wire to the oem gauge sensor the gauge is receiving power from two sources, this WILL change the gauge reading and cause erratic gauge readings.

When using the SPAL sensor, you may connect the white wire to the green wire instead of ground. (please see attached diagram for reference) Because both the green and white wire can receive input signals at the same time, we normally ground the white wire to give it a value of zero. When you connect it to the green wire, the green wire and the white wire receive the same signal. This increases the resolution on the green wire.

Programming:
As stated earlier, we designed the PWM to allow the fans to run almost all the time. It is meant to allow the engine temperature to increase to the thermostat rating, then remain there. The old 185/195 switch makes the coolant warm to 185/195, then cool to 165/175. Then warm back to 185/195, then cool to 165/195. The PWM varies the fan speed to keep the engine coolant at an optimal temperature (the thermostat rating).

The PWM does not care which way the sensor travels (voltage increases as temp increases, or voltage decreases as temp increases). When properly programmed, the PWM will increase the speed of the fan to the thermostat rating and hold the temperature there. If the vehicle is taken on the highway and the coolant can decrease, the fan will slow accordingly. The fan will most likely not turn all the way off. Though the fan is running, the air moving through the radiator is greater than the amount being pulled by the fan. The fan will then begin to "freewheel" as we are not supplying enough power to overcome the force of the air.