How To Install a AVCR in a 240SX S14

How To Install a AVCR in a 240SX S14


The Apexi AVC-R is a piggyback style boost controller that incorporates several ECU inputs to help you dial in the desired boost levels. Like any other boost controller, the AVC-R uses a vacuum switching solenoid to delay the time your wastegate will open.

This AVC-R isn’t one of our personal favorites, as we prefer the simplicity of a manual boost controller. But for dedicated racers who want the flexibility of boost control, the AVC-R has a host of additional features that can give you the edge in any racing platform.


Popular among the drag racing and the front wheel crowd, the AVC-R truly shines in it’s fuzzy logic learning mode. This mode is a self learning mode that lets the AVC-R adjust the boost levels based on speed for optimum fuel injector duty cycle and traction. The only true drawback when using this feature is that the AVC-R only displays the speed in KPH, and will require calculation on the fly if you are reading the Vehicle Speed Sensor (VSS)

If all things are equal in your turbo system, installation and dialing in the AVC-R is very easy and straightforward for the average shadetree mechanic. Today I’ll be showing you How To Install a AVCR in a 240SX S14, with a KA-T or a turbo kit on a KA24DE. This 2.4 liter truck engine is stout and has gobs of torque, unfortunately due to it’s undersquare design it’s not meant to rev as high as many would like.

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To begin our How To Install a AVCR in a 240SX S14 Guide, you will need to open your passenger side door and slide the passenger side seat as far back as it will go. The ECU is located behind the passenger side kick panel, and you will need to access the ECU to properly wire in the Apexi AVC-R.



Remove the small plastic pop rivet that secures the upper tab to the chassis, and pull this panel away. You should see the KA24DE ECU secured by 3 10mm nuts, remove these nuts and pull out your ECU so that you have the room to solder / tee / install the AVC-R.


With the ECU removed, undo the 10mm bolt that secures the ECU harness to the computer. Before unplugging your ECU, take this time now to disconnect the negative terminal on your battery to prevent any damage to your ECU. Now open the white plastic protective cover to access the back of the ECU harness. You are now ready to begin wiring in the Apexi AVC-R boost controller.


The AVC-R differs slightly from the Apexi Super AFC install in a 240SX, but the same two wire grounding process can still be found. Remove the flying loom and backhalf of the AVC-R harness and let’s begin with the RED power wire on the Apexi harness.




Take the RED AVC-R power wire and you can tee this into one of two locations, PIN 61 on your KA24DE ECU. With the power wired in, take the BLACK wire and the GREEN AVC-R wires and wire them into PIN 50 on your ECU.

Remember that the spacing here is critical, and that it’s imperative to have the GREEN wire closer to the ECU than the BLACK wire. Apexi will not honor any warranty if these wires are not properly connected or wired in.


Next take the GRAY AVC-R wire for Throttle signal, and the wire you will be teeing into is your PIN 23 on your KA24DE ECU. Next is the VSS or Vehicle Speed Sensor wire, the WHITE wire on your AVC-R harness, this goes to the KA24 PIN 26.

The last wire is the Purple wire for the injector duty cycle interface, this wire on your KA24DE ECU is PIN 102. Make sure this connection is clean and does not have excess solder, as the change in resistance could adversely affect your injector performance.

You have now completed our How To Install a AVCR in a 240SX S14 Guide, please leave any questions or comments below!

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