Project NSX: Part 17 – ECU Master PMU16

ECU Master PMU-16 Power Management Unit in an Acura NSXWe replace the NSX’s aging factory main relay and fan control modules with the ECU Master PMU16 Power Management Unit.  This also gives us the ability to not only control but log the draw of any device such as the fuel pump, radiator fan, front lift, windows, and more.

1992 Acura NSX Main Relay and Fan Control ModuleAccording to a few NSX specialty shops, it seems that after 3 decades the NSX’s factory main relays are finally giving up the ghost and failing fairly regularly.  Rather than replace the main relay, we decided to replace it (left black box) and the fan control module (right black box) with an advanced, computerized power management unit (aka: “PMU” or “PDM”).

ECU Master PMU-16 replacing the Main Relay and Fan Control Module in a 1992 Acura NSXPMUs replace traditional fuses and relays in the electrical system and are widely used in the build of high-end dedicated race cars.  They are usually solid-state, ‘intelligent’ digital modules that can data log the voltage and current draw from any of the channels that it powers, are self-resetting, can help diagnose issues, can be programed with math operations and logic for controlling outputs, and transmit all the data via CAN to the ECU or digital dash.  This opens up endless options on how to configure the electrical system of a car.  Now that they are becoming more readily available and affordable, PMUs are seen in the builds of more home-built cars and in the aftermarket in standalone wiring harnesses to power everything from headlights, turn signals and windows, to replacing a relay box in a street car.

ECU Master PMU-16 Power Management Unit Power Distribution ModuleThe ECU Master PMU16 is a 16-channel, solid-state power management unit which features 16 analog inputs, 10 (25amp -continuous) outputs and 6 (15amp -continuous) outputs with overcurrent and overheating protection.  Current and voltage is measured on each output and outputs can be paired to increase the current capacity of a device.  The total continuous current output is 150amps, so it is a very powerful device that requires a proper connection to the battery of the car.

The PMU16 also features a 3D accelerometer and 3D gyroscope for logging and crash detection, as well as a 3-day super capacity for backup power.  2-CAN interfaces and up to 48 user-defined messages make the PMU16 an integral part of the data analysis and monitoring of the car.

NSX CAD model of ECU Master PMU16 MountUsing our what turns out to be extremely beneficial CAD modeling and 3D printing skills, we drew up this bracket for our PMU16.

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