The Apexi VAFC II is a piggyback device that has been designed specifically for the Honda variable cam timing system known as VTEC. Installing this unit will allow you to adjust the fuel trims and move the VTEC crossover point for dyno tuning. If you are here and looking for a Super AFC primer or How To, or maybe you are looking for the Honda VTEC AFC Hack please open in a new window and return.
Today we’ll be installing a Apexi VAFC into a 1998 Acura Integra GSR DC2 equipped with the B18C1 engine. This Integra has a custom turbo kit built around a CXRacing turbo manifold and GT35R turbocharger. Because there’s a few versions of this VAFC controller in existence, the part number that’s relevant to this How To DIY article is part number 401-A915, although 401-A815 also applies.
The first order of business in our How to Install a VAFC in a Acura Integra DC2 Guide is to locate your P72 ECU. Your Integra ECU is located in the passenger side footwell, and must be removed from behind this panel for access. Disconnect the negative terminal on your battery and go open your passenger side door. Slide the passenger side door back as far as it can go to give yourself as much room as possible.
There’s a plastic pop screw that secures this panel in place, unscrew this pop screw and you can pull off the plastic kick panel. Your P72 ECU is secured to the chassis bracket by two 10mm nuts, undo these nuts to free your Honda ECU.
Like the Super AFC and the Super AFC NEO, the VAFC comes with a flying loom that can be disconnected from the engine ECU harness. Take this harness out now and you’ll be wiring this into your ECU harness to complete the installation of your VAFC and our How to Install a VAFC in a Acura Integra DC2 article.
There’s a few wires that’s part of the VAFCII wiring harness that you will not need. Because your Integra is not a RSX or equipped with the K series line of Honda engines, you will not need the two wires labeled RDC signal and the TCC cam signal.
These two wires are for i-VTEC applications only. You will also not need the twin VTC wire, just the orange VTC wire, as this most commonly applies to larger engines with a variable timing controller like the VQ35DE.
How to Install a VAFC in a Acura Integra DC2
To begin let’s take some time to survey the wiring diagram that should have come with your Apexi VAFCII. This wiring diagram differs slightly from the SAFC versions as there are additional wires that must be teed in so that the VAFC II can control your VTEC system.
We are starting with the power wires which will supply your Apexi VAFC II with switched power from the ECU. Your VAFC may differ depending on the generation or production date, but most VAFC II’s have dual red power wires. Alternately there’s some late model units with the secondary red wire with white stripe, much as the AFC NEO does.
The wire you are going to be connecting this to on your Honda P72 ECU, is on the A connector which is the 32 pin connector on your P72 OBDIIA ECU. The wire in question is the pin A11, which is IGP1 and is switched power supplied from the ECU. If you have two red wires on your VAFCII, make sure to wire them in as instructed. Do not combine these two wires and solder them in, wire them in separately giving yourself an inch between both wires.
The next wire on our How to Install a VAFC in a Acura Integra DC2, is the ground wires, which will be brown and black on your VAFCII harness. This like the red power wires will need to be connected to the same wire, with the same spacing only the brown wire MUST BE closer to the ECU. Proper installation of these dual wires is imperative to your Apexi VAFCII operate and tune your Honda correctly.
The ground wire on your P72 oBDIIA ECU is on the same 21 pin A plug on your ECU harness. The ground wire you want to tee the brown and black wires into is A9.
At this stage of our writeup, you should now have power and ground going to your VAFC2. Now we’ll begin wiring in the rest of the sensor inputs your VAFC II needs. Let’s begin with the engine speed (RPM) wire which is GREEN on the VAFC2 wiring harness.
Next we’ll be moving onto the GRAY wire of your VAFC2 harness, this is the throttle position sensor reference. This wire should be teed into 16 pin D plug on your OBDII ECU. This is the last plug on the opposite side of the 32 wire A plug. The wire for the TPS on you Honda is D1, and should be a 0-5 volt reference.
The next wire of your VAFC2 install is the manifold absolute pressure (MAP) sensor reference. The wire color on your Apexi harness is yellow and white, which should be spliced into the D3 pin on the 16pin D plug. Cut this wire in half and leave yourself enough slack on either end to work with. You will be wiring in the yellow wire to the sensor side or the engine side of the ECU harness, while the white side goes to the ECU side of the D3 wire.
With the RPM, MAP and TPS wires completed, now its time for the purple and pink wires of your Apexi VAFC2 to complete the VTEC control of your piggyback computer. Much like the MAP sensor wire on the D plug, you will be cutting the pressure reference and splicing in the VAFC2.
The VTEC solenoid wire is located back on the 32pin A plug on your OBDII P72 ECU. The wire for the VTEC solenoid is A8 and is located directly next to the ECU ground that we spliced the brown and black wire to. Cut this wire in half, and run the PURPLE VAFC2 wire to the ECU side of PIN A8 and the PINK wire on the VAFC2 directly to the engine side of the ECU harness.
Congratulations, you have now successfully completed our How to Install a VAFC in a Acura Integra DC2 Guide, for more on how to setup your VAFC2, click here.