Piggyback Heaven – How To Install SAFC NEO in a KA S14

Piggyback Heaven – How To Install SAFC NEO in a KA S14


The SOHC and DOHC versions of the KA24DE are something of an enigma, with enough torque to satisfy the entry level enthusiast but not enough of anything else to be noteworthy. And although turbocharged versions of the KA have been successful in many degrees, some more extreme than others, it still remains a very unpopular motor of choice for those wanting forced induction.

Blame it on the undersquare nature of the engine, or the relatively low redline compared to other engine choices but the KA is still a very viable and stout base on which to build your project 240SX.

Today we’ll be showing you how to Install SAFC NEO into a 1997 Nissan 240SX with a DOHC KA24DE, you do not need a turbocharger or supercharger kit for this type of install and can use this device to safely maximize the potential of your bolt-on modifications. As the AFC NEO has throttle point based maps you can also tune your vehicle to maximize the gas mileage in your 1989-1998 Nissan 240SX.

Piggyback computers are definitely something of a throwback to an era where EEPROM programming was not as common as it is now and options were limited for those wanting to bolt on a turbo kit. While they do have their limitations, the SAFC NEO is NOT dangerous for your motor, nor will it instantly melt, damage, shatter your engine’s rods or pistons unless you do not know what you are doing.

If you are not comfortable doing this modification or any modification on this site, please stop here and take your vehicle to an experienced mechanic who can both install and tune your vehicle.

The Super AFC in any form or generation is a tuning device, and as such it’s as dangerous or as helpful as any EEPROM programmed ECU or similar tuning device can be. People who spread false rumors or statements about the Apexi Super AFC are often just sheep who repeat the same line they’ve heard over and over in the “automotive forum” of their choice.

You will want a datalogger or scanner of your choice to properly read the values in your ECU and tune it accordingly, if you are not familiar with how to datalog or use a scanner please refer to our How-To here.



Undo the negative terminal on your battery, if you own a stock radio now is a good time to secure your radio code unless you do not have it.

Next locate your stock KA24DE ecu, which is behind the lower passenger side kick panel below and to the right of your glovebox. Undo the 10mm bolt that holds your ECU/PCM harness in place (shown by the blue circle ) and unplug your ECU harness.

It would be a good time to review your SAFC installation manual for the specific way in which Apexi wants you to install your AFC NEO.



For the purpose of this writeup, we’ll be assuming your vehicle is equipped with a N60 Mass Air Flow Sensor ( MAF ), if so your SAFC settings will be 2 in and 5 out.

Tools you will need for this install :

  • Soldering iron
  • Solder
  • 10mm wrench
  • wire cutters

Let’s begin by taking a look at our wiring diagram for your 1995-1998 S14 KA24DE ECU (OBDII)



Let’s begin with the ground wires, which must be wired in correctly in order for the AFC NEO to work reliably. Locate your ECU ground (Pin 50) and splice into the wire, closer to the ECU side of the harness.



You will be splicing into the ECU Ground wire the brown AFC wire, make sure to solder the connection so that it doesn’t come loose during operation. Next you must splice another section of the ECU Ground to splice in the black AFC NEO wire, which must be spliced upstream of the ECU harness, roughly an inch or inch and a half away from the brown AFC NEO wire you just spliced in.

Now with the ground completed, turn your attention to the ECU power wire, which is Pin 61. If you own a previous version of the SAFC, or SAFCII, all you will need to wire here is the solid red AFC wire to your ECU Pin 61.
If you own a NEO, follow the instructions on how to connect your red wire and red with white stripe wire to your ECU pin 61.
This wire is a black wire with white stripe, and we’ll be teeing the red wire with white stripe and red wire from your AFC harness.

Wire in your red wire and red with white stripe on the NEO harness to pin 61 of your KA24DE ECU, and duplicate for the red wire in the same method as you did the ground wire. Make sure the red wire with white stripe is closest to the ECM.

Now find the yellow and white MAF wires on your AFC NEO harness.




Next we’ll be wiring up the MAF connection for your KA24DE, remember that this writeup is assuming you are using the N60 MAF, in which case the settings are 2 in and 5 out.

Locate your MAF wire, which is Pin 47 on your KA ECU and cut it leaving enough space on either side of the wire for you to splice and solder. Solder the Yellow wire, which is the AFC NEO output to the ECU side, and solder the white wire to the engine side of your MAF connection.

Next up is your throttle position sensor, which is the gray wire shown above. Find your Throttle Position Sensor input, which is Pin 23 on your KA ECU. Splice into this wire so that your AFC NEO has a reference of throttle blade position.

Finally to complete the basic install of your AFC NEO, you will need to wire up the engine speed sensor ( RPM ) so that your AFC NEO knows what RPM to reference and therefore correct. The RPM or tachometer output is Pin 3 on your KA24 ECU, splice into that with the gray wire so that your basic AFC NEO install is complete.

High and Low Fuel Maps
High and Low Fuel Maps

Advanced setup – Blue Wire Mod

Some people may be wondering just what the blue wire mod is, and how to properly set it up so that you can track real time data of your choice. The blue wire on your AFC NEO has long been an optional input for those wanting to monitor other data that isn’t part of the AFC NEO’s operation.

While most people wire this unit in for narrowband 02 reading, the 1995-1998 Nissan 240SX has an knock output which you can also tee into to view the real time knock data for your KA.

For 02 reading : Narrow Band 02 wire – KA ECU PIN 46

Knock reading : Knock wire – KA ECU PIN 54

To find out how to perform this mod, check here.

How to setup your AFC NEO 

Go into the menu and select sensor type as “Hot Wire” as your 240SX operates on a MAF and will require a setup of 2 in and 5 out.



Go into the car setup, and change the cylinder value to 4 and set the “thr” setting to the arrow pointing up and right.



You now know how to Install SAFC NEO into your KA24DE powered 240SX!