Heater fan
 

Hi all,

I have an Impreza classic 2.0. I tend to do subtle mods for general improvements but it's not the most economical car ever, slightly underpowered and 4WD.

I read something on these forums that got me thinking. Reducing electrical load will reduce alternator load.

In the Impreza there is very little air flow without having the heater fan on. It has 4 speeds, position 0 is off. The speed is controlled by a resistor pack and it gets very very hot. It's excess heat is sinked into the air flow from the fan. This probably explains why the output is always warmer than outside temp. On full speed, the fan gets full 12V and the pack does not get hot.

I have wondered if the resistor pack could be replaced by something more sophisticated that produces less heat and puts less load on the alternator when used on the lower speed settings.

Replace it with a fan motor wound for multiple speeds. That's just about the only way to go about it cheaply.

Another alternative, although it would probably be cost prohibitive, would be adding voltage step downs to the lower speeds.