There is a Nasioc thread over increasing the voltage of the alternator (up to 14.8v) to improve performance. They insert a diode into the ALT-S fuse in the engine bay and it tricks the voltage regulator to put out a bit more voltage.
One aspect of the BRZ EPAS retrofit I was concerned about was the additional load on the electrical system. I don’t run an aftermarket stereo (at the moment, no stereo at all), but I have added HIDs and a smaller battery. On occasion, my power assist would cut out at low speeds; it is inconsistent when it happens, though.
To trick the voltage regulator into putting out about 0.5 volts, we can install a diode with the ALT-S 10a fuse. User 2.5x_sleeper over on subaruforester.org has a good write-up if you want to build your own. I did not want to build my own so I opted to buy a resettable diode from Aussieland.
The diode isn’t cheap, but I was looking at it from the stand point of buying a high output alternator. Rather than spending hundreds of dollars I could spend $50 instead.
The diode arrived pretty quickly, tapped inside a piece of cardboard.
We need to replace it with the ALT-S 10a fuse.
The diode is directional, so when you install it and you get a battery light on the dash, then flip the diode around.
At idle we have 14.6v now compared to the 14.2v before. The car seems more responsive, although it’s hard to say for sure. The steering seems a little more consistent as well, but that could be in my head. I probably need to swap the diode and fuse out a few times to see if there is any difference.
Up next, we are adding a controller to the BRZ EPAS system.