Piggyback computers like the Apexi Super AFC enjoyed a good run in the mid 90s as tuners learned how to install a SAFC and tune it. Capable of controlling your fuel trims by altering your engine inputs, you can use the SAFC to adjust fuel trims for any bolt on modifications on your VQ35DE.
Modifications like intake, intake plenum spacer, headers and catback exhaust are perfect for this kind of modification. More aggressive mods like a turbo kit, supercharger kit or nitrous can also be used in conjunction with the SAFC, so long as you know how to tune it.
Before we begin, this DIY article is for those comfortable wiring piggyback computers into their own cars. If you feel uncomfortable or uneasy at any time, stop now and take your vehicle to an experienced mechanic. Improper installation and operation of this Super AFC can result in engine damage, you have been warned.
To begin our How To Install a SAFC in a Infiniti G35, you will need to locate your Nissan / Infiniti ECU. This unit is located under the passenger side dash and must be unplugged for you to access the wires in question.
First open your passenger side door and slide the seat back in it’s furthest position. After this step, you will open your hood and pop the top of your battery cover to disconnect the negative terminal on your battery. If you have a stock or factory radio, you will want to find your radio code before doing this.
Grab the plastic trim as shown here, and pull away from the frame of the car pulling inward and up. This entire strip can be removed whole, and set to the side.
Now that you have the door sill plastic removed, you must remove the corner kickpanel plastic cover. This too is pushed in using metal clips, and to remove this plastic cover you will need to undo the screw located here.
After removing this screw, you can pull away on the corner kickpanel and remove. There are metal tabs that hold this plastic panel in place, make sure you don’t lose any of these metal clips during the removal process.
Now that you have this plastic panel removed, you can now remove the lower plastic shield that covers the ECU. Locate the black panel under your dash and pull towards you to release from it’s locked position. Pull downward and this panel should peel away, revealing your Infiniti ECU and harness.
There’s a plastic clip that must be depressed before you can swing open the ECU connector. Depress this black plastic clip and pull downward to release the ECU and the connector.
Once this plastic clip has been depressed you can pull towards you to open the lever. Take note that the lever and connector will run into the bottom of your dash when fully opened. When you go to reconnect this harness, it’s easier to connect it with this lever half open, so that it doesn’t run into the glovebox door hinge.
Pull down on this lever to release and then remove the entire ECU connector. You will need to remove the plastic covers on the backside of this plug in order to complete our how to install a SAFC in a Infiniti G35 guide.
Because your VQ35DE is a MAF driven engine, you will be using the MAF / Hot wire set of instructions for your Apexi Super AFC.
If you own an older AFC, you won’t have the dual power wires as shown above with the red wire and red wire with white stripe. If you do own a AFC NEO, you will have to connect these wires in the same manner as you connect the ground wires, as shown below.
Begin with the black wire which is the low reference ground wire, and the brown wire, which is your secondary ground wire. You will be connecting these to the ground wires of your Infiniti G35 ECU.
The chassis ground provided by your Infiniti ECU is located on PIN 1. Make sure to wire the brown secondary ground wire closer to the ECU than the black wire. Another important step in our how to install a SAFC in a Infiniti G35 guide is to make sure that there’s an inch between the brown and black wires.
Power is the next wire you’ll be teeing into. Remember if you own a AFC NEO, there’s going to be two power wires, the red wire as well as the red wire with white stripe. Make sure you wire these like the black and brown ground wires, with the same one inch gap between the wires. The power wires for your Infiniti ECU are 119 and 120.
The green RPM AFC wire is the next one we’ll be wiring up, and this green wire goes to PIN 13 the BROWN crankshaft position sensor wire. The next wire is the gray TPS wire, and this one tees into pin 50, which is a white wire. Because the maximum voltage range for your VQ35DE is less than 4.75V at WOT, you may need to program your AFC NEO’s range of throttle. If you are not sure how to do this, check out our How To Setup a AFC DIY Guide.
Now you should have two wires left over to connect, the white wire and the yellow wire for your VQ35 Mass air flow sensor. You will need to cut the ECU wire in half, leaving enough wire on either side to work with. You will be connecting the Yellow wire to the ECU side of the harness, and the WHITE wire to the ENGINE side of the harness.
This wire is PIN 51 and it’s orange, make sure you cut this evenly and leave enough space to work with.
You can choose to use the clips Apexi provides, or simply solder the wires in permanently. Congratulations, you have now successfully setup a Super AFC and know how to install a SAFC in a Infiniti G35. There are a few optional wires left over that you can choose to hookup depending on your needs or usage.
Optional – KNOCK WIRE – PURPLE WIRE – This wire is the optional knock sensor output, and you can connect this wire to PIN 15 which is a white wire on your VQ35DE.
BLUE WIRE – 02 sensor mod – This is explained in our How To Hack your AFC series, but the blue wire is an optional output for your 02 sensor. When connected to one side of your VQ35DE exhaust banks, you can check real time and see what air fuel ratio your G35 or 350Z is running at.
That does it for our how to install a SAFC in a Infiniti G35 DIY Guide, if you have any questions or comments please leave them for us below.