Audi S4/A4 Boost Gauge Installation

The APR Boost Gauge utilizes a VDO boost gauge contained in a vent-replacement pod. Designed with Pro-E for the best in fit and finish, giving you a factory like look and feel. The gauge itself is a 52mm mechanical VDO gauge giving very accurate and reliable boost and vacuum readings. The Gauge Pod can be installed in anyone of the three center vents. The installation illustrates a center vent installation.

Installation Procedure:
Step 1
Remove the Vents. Pull the vent assembly out slowly with your fingers. If needed you can use a flat head screwdriver to carefully persuade the casing. There is a lighting wire that runs to the vents, be careful not to damage it during the installation. Remove the rear flap valve. Snap out from one side, and unhook from the other. Remove the vent where you wish to install the gauge pod. The pod will fit in any of the three vent spaces.
Step 2
Snap the gauge pod into the vent housing You can adjust the angle of the pod by turning the adjustment screws on the rear.
Step 3
Attach the white nylon line to the gauge with the supplied hardware. Before tightening the assembly make sure that the line is fully inserted, and that the olive fitting is oriented correctly. Using a 1⁄2 inch and 1⁄4 inch wrenches, tighten the fixture while making sure the nylon line has not backed out. The ferrule fitting will crimp onto the nylon once torque is applied.
Step 4
Drill a small hole into the side of the center vent duct to pass the signal line through. Place the hole in the lower left corner of the duct. A 3/16 inch ~ 3.5 mm in diameter is sufficient. If you wish to later run a power line to the VDO gauge (for lighting), you may need to enlarge the hole to accommodate the additional line. Be sure to leave enough clearance so that it will not interfere when reinserting the vents.
Step 5
Remove the driver side lower dash panel. Access the four 8mm mounting bolts. You need to remove the fuse panel, and the two rectangular trim pieces. A small flat head screwdriver can be used. While lowering the dash panel, pay close attention to the OBDII / VAG port, and foot well lamp cables as they need to be disconnected. With the lower dash panel removed, you will be able to see the nylon hose emerging from the center vent duct.

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