Earthing Kit
[ Home ] [ Up ]

A grounding cable or "earthing" cable kit can equalize the ground potential across the engine compartment.  It is important to use heavy gauge copper cable.  Copper is a much better conductor of electricity than aluminum or even steel.  Engines used in todays automobiles are arrayed with many electrical sensors.  Lowering the ground potential across the engine bay results in lowering electrical sensor noise increasing the vehicles computer sensors signal to noise ratio.  The result is often improved smoothness at high RPM.

There are several kits that can be purchased online including from NISMO.  However I decided to build my own based on my knowledge of electrical engineering.  The other kits use up to six individual cables.  I decided to use four.  The following picture illustrates the connection path for my grounding kit.

The first cable will connect the battery ground to a chassis ground point on the left side of the engine bay.  This will enhance the ground conduction path for the various ground wires attached here as well as the chassis ground.

The second cable will connect this chassis ground point to the left front of the engine.  I choose a large bolt here less than 2 inches away from the engine ground point.  I chose this due to the size of the bolt and proximity to the alternator.

The third cable will connect the left front engine to the rear of the engine.  I chose this point for it's proximity to the MAF sensor.

The fourth and final cable in my kit will connect the rear of the engine to the right front of the engine.  I chose this point to balance the right side of the engine compared to the right and its proximity to electrical controls.

Here are the special tools and parts I used to make my kit.  In addition to these I used common hand tools such as wrenches and sockets.

Special Tools
Heavy Gauge Crimper From Local Electrical Supply.	Tin Snips From Local Hardware Store.	Soldering Torch From Lowes And Heat Gun From Local Electrical Supply.
Close Up Of Heat Shrink Tubing And Lugs From Local Electrical Supply.	Synthetic Moly Grease From Auto Zone For The Battery Connector.	Battery Connector And Felt Pads From Auto Zone.
Cable Armor From Auto Zone Protects the Cables.	Bulk 4 Gauge Cable From Local Stereo Shop.	Example Cable After Cutting To Length, Crimping Lugs, Soldering Lugs, And Applying Heat Shrink.

The OEM ground battery connector does not provide for attaching additional cables.  Therefore I replaced it with a similar connector from Auto Zone that has a provision for adding additional cables.  The first cable is routed out of the battery compartment by making a slit in the rubber boot.

Battery Ground Connection
Cut-Off OEM Connector.	Installed Connector With Cable #1 And OEM Chassis Ground Cable.	Routing Of Cable #1 In Battery Compartment.	Cable #1 Exits Battery Compartment.

The chassis connection point for the first cable requires the removal of a hood sensor to gain access to the ground bolt.  Because the ground bolt is shorter than the bolts used on the hood sensor, I swapped the ground bolt with one of the hood sensor bolts.

Chassis Ground Point
Removal Of Hood Sensor Requires Patience And Small Fingers.	Cable #1 And First End Of Cable #2 Secured.

The second cable and start of the third cable is secured to the left front of the engine.

The third cable and start of the fourth cable is secured to the rear of the engine.

The fourth and final cable is secured to the front right of the engine by removing the engine cover.

Front Right Connection.
Engine Cover Bolt/Nut Locations.	This One Is A PITA.	Engine Cover Removed.	Fourth Cable Secured To Front Right Of Engine.

All logos and trademarks are copyrights of their respective companies.  This is a private non-profit personal site.  This page was last modified on 10/12/08 .