Once I read an article in Import Tuner magazine not too long ago (Turbo & High-Tech Performance Magazine did a similar article in 2003) about how they installed a kit on a WRX that belongs to one of the magazine's writers. They gave a full How-To and feedback with dyno results . Granted many people will state that low HP gain readings from a dyno can be fluctuations and inaccurate. I personally believe that any help to the electrical system can be a benefit that could result in gained HP (primarily from stronger and more consistent spark for a better fuel burn).
My primary reason for even considering taking the time to perform a Grounding Mod upgrade would be to better supply the OE locations with a more direct ground connection with the battery. Also, as the pics below show, as 20yrs of grime & weather have worked their way under the hood the stock ground wires have become tarnished and slightly corroded. I have little flickers in the dash lights when activating the brake light switch and also the turn signals. With a strong battery and clean terminals, this can greatly be associated to the OE grounds becoming weak over the years.
I've looked at all the kits that are deemed "professional" that many of the companies sell for $30-$70. While they look impressive and pretty, I can't justify that kind of cash spent. Being an old car audio salesman & installer, I've acquired tons of connectors and various lengths of good quality wire. So I went through my collection and came up with a 20' length of Lightning Audio 10 AWG wire (black) and plenty of insulated 10 AWG ring terminals. Time to get busy!
Looking a the engine bay I located 4 primary locations that required upgrading and attention. Two of the locations are the most obvious, which are the left and right strut towers, the third location was the coil pack mounting point on the intake manifold and the fourth was the alternator bracket. I personally added the radiator support as a fifth location, but that is mainly because I have my Hella Supertone horns grounded there. I loosely ran wire to the DS strut tower and the intake manifold to measure out my two main runs. I used the mounting points for the coil pack as a jumper/distribution point to make a run to the near by alternator and out to the PS strut tower. After I had my lengths of wire I headed to the work bench to assure a solid connection between the ring terminal and the wire. Soldering time!
Most may consider this over kill, I consider it cheap insurance. I removed all the plastic insulators that were on the ring terminals because I didn't want the yellow plastic showing under the hood, plus I have plenty of heat shrink tubing to add at the end. With all the ring terminals crimped and soldered, I added the heat shrink tubing to seal off the job and coated everything lightly with dielectric grease as a last bit of insurance against future corrosion. I used my cordless drill and soft bristle wire wheel to clean up the OE ring terminals and brake parts cleaner to remove any remaining road grime. Apply more dielectric grease and add the new ground wires.
Started the old girl up and saw an immediate improvement at the battery terminal since my aftermarket terminals (positive) also have a voltage gauge. My normal reading at start up would be 13.8 to 14.0. After the mod, 14.3 to 14.4 AND a much smoother idle. I haven't had much of a chance to put many miles on it yet to see a MPG improvement but I have noticed a smoother run through the RPM range while running it hard.
