Bravo
Member
I am thinking of installing a Spal fan an want to know what one to order and how easy. Rick
Spal Fan install
- Thread starter Bravo
- Start date
Here is a diagram of the electrical circuit in my e39 BMW, which illustrates the circuitry. You only need half of this circuit, but it shows all the essential components.
To do this, you do need to be able to install a simple electric circuit into your car that uses a relay to power the fan. Using this circuit as a guide (see bottom left), you would need to identify an appropriate temperature switch (VDO made these for BMW for decades, and still sells them), and determine where to install it. The temp switch basically allows power to flow once it reaches a certain temperature. It is installed in the cooling system somewhere and in this circuit it acts as a ground. I know there are thermostat housings for our engines that have mounts that would work. Not sure if you have one of these.
The temperature switch then connects to the relay, using switched power so that the fan only runs when the ignition is on. For a one speed fan, you can follow the portion of the circuit shown here to the relay on the top of the picture. The current from the temperature switch initiates the relay by grounding the circuit when it heats up. The relay then passes power from the battery to the fan. Obviously, you need to find a source of switched power in the engine bay for one relay connection, and connect the relay to the battery for another. You also need to find a place to mount the relay and to make connections from the relay to the fan and from the fan motor to ground.
As to the fan itself, you need to size the fan to the shroud you will be using. Assuming you have a shroud, you can either size the fan to the opening in the shroud, or try a slightly larger size and plan to cut the opening to fit a larger size. I would think the portion of the shroud that extends outward toward the stock fan would make installing a Spal difficult, soI would think you would want to plant to cut the shroud to remove this lip and allow the fan to mount directly onto the shroud.
Oh, and you need to be very confident in your ability to make this system reliable. It will be the only thing keeping your engine cool.
To do this, you do need to be able to install a simple electric circuit into your car that uses a relay to power the fan. Using this circuit as a guide (see bottom left), you would need to identify an appropriate temperature switch (VDO made these for BMW for decades, and still sells them), and determine where to install it. The temp switch basically allows power to flow once it reaches a certain temperature. It is installed in the cooling system somewhere and in this circuit it acts as a ground. I know there are thermostat housings for our engines that have mounts that would work. Not sure if you have one of these.
The temperature switch then connects to the relay, using switched power so that the fan only runs when the ignition is on. For a one speed fan, you can follow the portion of the circuit shown here to the relay on the top of the picture. The current from the temperature switch initiates the relay by grounding the circuit when it heats up. The relay then passes power from the battery to the fan. Obviously, you need to find a source of switched power in the engine bay for one relay connection, and connect the relay to the battery for another. You also need to find a place to mount the relay and to make connections from the relay to the fan and from the fan motor to ground.
As to the fan itself, you need to size the fan to the shroud you will be using. Assuming you have a shroud, you can either size the fan to the opening in the shroud, or try a slightly larger size and plan to cut the opening to fit a larger size. I would think the portion of the shroud that extends outward toward the stock fan would make installing a Spal difficult, soI would think you would want to plant to cut the shroud to remove this lip and allow the fan to mount directly onto the shroud.
Oh, and you need to be very confident in your ability to make this system reliable. It will be the only thing keeping your engine cool.
Bravo
Member
Thanks Ohmess. I will be converting this in spring.