The Subaru Impreza WRX is the sport edition of this particular model, featuring upgraded suspension, body features and engine performance from the factory versions. A standard electrical setup of the WRX features a connection that runs from the positive terminal of the battery, through the engine and back to the negative terminal of the battery. While this works, there is a chance to gain a bit more power by increasing the efficiency of the electrical connection. If you would like to ground the electrical setup in your WRX, you may do so at home to save money.
Open the hood of your WRX and disconnect the positive and negative terminal battery cables. Locate the grounding wire that connects the battery to the metal frame of your engine bay. The battery is located on the driver side of the engine in these sports cars. Unscrew the bolt that holds the grounding wire connector to your car and move away.
Measure the length from the battery to the passenger side strut chassis. Cut a piece of wire that replicates the length of these two engine parts, then attach a metal O terminal connector to each end. Connect the wire from your battery to this strut chassis, then reinstall the bolt with your hands.
Disconnect the ground bolts to the passenger side of the intake manifold and throttle body. Measure the distance between these engine parts, then cut and assemble a new grounding wire. Unscrew the bolts that hold your WRX's intercooler to the top of the engine, then move away to access the throttle body. Connect this wire between these two engine areas.
Measure the length between your throttle body and the driver side of your manifold. Unscrew the bolt on this area of the manifold. Cut and assemble a piece of wire with two O terminal connectors, then attach this wire to connect both of these parts. Hand-screw these bolts, but do not tighten just yet.
Remove the screws that hold together the alternator cover, then lift this plastic piece away from the engine bay. Loosen the grounding bolt on the Subaru WRX's alternator, but do not remove completely. Measure and cut a wire that will extend from this area to the negative terminal of your battery. Assemble this wire with a U connector on one of the ends, then connect the wire and hand-screw in each of the bolts. The end with the U connector slides into the grounding bolt of the alternator.
Tighten all ground bolts to secure the wires into place. Reinstall any parts you may have removed to access these engine parts, as the setups in Subaru WRX cars vary from year to year. Zip tie these wires together to create a clean engine space, tightening each of these wires and reducing slack.
