Last Updated
10 October, 2004

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Installing an APEXi AVC-R 
Electronic Boost Controller

The APEXi AVC-R is an electronic boost controller with many advanced features designed to give you maximum control over your turbo. I chose it without really knowing whether I would use its many features, mainly on the premise that "it's better to have it and not need it than need it and not have it." I also liked the way it was sized to fit in the ashtray well of the MKII, as shown below:
AVCR_Module.JPG (96419 bytes)
This unit was installed as part of a larger project which included a J&S Safeguard, GReddy Intercooler, SPAL IC fan, GReddy Oil Catch Can, and some gauges. Because of the scope of my project, some of the photos might show more disassembly than is actually required. It's also likely that the photos don't always match EXACTLY what's in the text. As is often the case, I would have changed the sequence of a few things if I had to do it over again. 

Finally, remember that this is only a guide -- not gospel. What you do to YOUR vehicle is YOUR responsibility. I do not endorse, approve, authorize, or otherwise encourage you to make alterations to your vehicle. Be careful, and recognize the dangers associated with modifications to your vehicle's critical systems, like electrical, engine, brakes, etc.

Please contact me if you have comments or suggestions about the article or the project, or if you find errors on these pages.

Tools/Materials Needed

  • Soldering iron & solder (low wattage)

  • Phillips and flat-bladed screwdrivers in various sizes

  • 10mm and 12mm sockets with assorted extensions

  • Sharp Xacto knife or similar cutting tool

  • Wire cutter/stripper tool

  • Electrical tape

  • Assorted wire ties

  • Ribbed cable sleeving (Optional)

  • Braided cable sheathing (Optional)

  • 3-10 feet of 22 AWG hookup wire in 6 different colors

Doing It

The kit includes many individual pieces designed to assist in the installation, as shown here:
avcrkit.jpg (51520 bytes)
In this photo, I have already addressed the major shortcoming of the kit, which is the inadequate length of the wire harness that leads to the ECU. For my 93 MR2 Turbo, I extended this section about 10 feet, then used a braided sleeving over the bundle. This harness section contains six leads, so it helps if you can use colors that match the original 22 AWG leads (Red, Purple, Green, Black, Gray, & White).

10 feet was more than I needed, but I figured it was better to chop some wire off than be too short. 

The first challenge was routing the wires. Since this was part of a larger project, I had quite a few wires to handle. Instead of repeating the procedure, jump to my J&S Safeguard installation guide to see how I routed my wires through the firewall.
I had already decided to mount the control module in the ashtray well, so I had a minor modification to make to that. After removing the ashtray, I cut a notch in the right wall of the inner housing to provide a spot to run the control module cable:
Fit AVCR 01.JPG (44218 bytes)
Although the ashtray lamp housing is still attached in this photo, I later removed it, as it was totally unnecessary.
I then installed the control module and ashtray housing back into the console...
Fit AVCR 02.JPG (77148 bytes)
...and routed the cable along the right side of the console to the rear bulkhead.
At the rear bulkhead, the control cable connector will fit into its mate, shown here (the black 12-pin connector):
Pull Wires 04.JPG (77291 bytes)
Once the control module was ready, I turned to the other three components: the pressure sensor, the solenoid valve, and the ECU connections.
I decided to mount the pressure sensor in the unused space below the cruise control unit, in the right rear of the engine compartment. This is both close to the boost line I wanted to use and relatively cool and protected:
Remove Cruise Control-01.JPG (84471 bytes)
First remove the two screws, then remove the cover.
Remove the cruise control cable and the three 10mm bolts that attach the unit to the body: 
Remove Cruise Control-02.JPG (68945 bytes)
Disconnect the electrical connector to the cruise control...
Remove Cruise Control-03.JPG (37321 bytes)
...and you can remove the unit. 
Disconnect the electrical connector for the right rear ABS sensor and to the security alarm horn, and you can pull the harness out of the way to make room for installing the pressure sensor:
Install Pressure Sensor-01.JPG (45340 bytes)
This leave plenty of working room, as seen here:
Install Pressure Sensor-02.JPG (36364 bytes)
I cut into the boost line that feeds the stock boost gauge sensor and installed a T-fitting to attach the stock sensor. I then installed a section of vacuum hose from the original T-fitting to the inlet of the APEXi pressure sensor. Here's a photo:
Install Pressure Sensor-04.JPG (77350 bytes)
The white cylindrical object is a filter on the line leading to the stock boost gauge sensor. The vacuum line at the bottom of the photo leads to the APEXi pressure sensor, and it has its own inline filter.
The pressure sensor was mounted to the wheel housing with two sheet metal screws. It must be mounted with the hose nipple pointing down. The wire harness provided with the APEXi unit was routed to this location, and a ribbed polyethylene sleeve was used for protection from abrasion and heat. The harness was just long enough to reach to this location after carefully routing it around the turbo and exhaust manifold:
Install Pressure Sensor-03.JPG (45209 bytes)
I installed another T-fitting on this line. One leg goes up to the APEXi pressure sensor through the supplied filter.

The other leg (leading away from pressure sensor) is connected to a brass compression fitting that changes the vacuum hose from silicone to 1/8" nylon tubing. The nylon tubing is much easier to run long distances and through tight spaces. This tube will be used for both the boost gauge I installed and the boost inlet on the J&S safeguard unit.

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