Earthing Cable and cool web page

[SILVER97LE]

I was looking at my350Z.com and I noticed the guy on there has a factory Nissan earthing cable (grounding).

http://www.my350z.com/gallery/groundingcable

What does this do?  

I did a google search for the cable and it picked up this site-

http://www7.plala.or.jp/tok/silvia/index-e.html#My_Silvia_Gallary

This is a cool page (half english / half Jap.).  The silvia on this page has a earthing cable also.  Maybe I should know what this is , but I don't.  Please enlighten me.  Thanks.

[SILVER97LE]

No responses?  Even guesses?  

The fact that he said the car (Z) ran smoother, made me curious.

[adey]

From what I've heard, these earthing/grounding cables supposedly make the car run smoother, and can sometimes give subtle power gains.
As I understand them (which I honestly can't say I do) they give the battery a much better ground, giving something like a better spark, stronger stereo radio reception, brighter lights (interior and exterior?), and generally eliminates any inefficiencies brought about by stock (insufficient) grounding of the battery.
I'm skeptical of anyone who claims significant power gains, but I don't doubt that on an older car, this could help smooth things out.
:shrug:

[KEIVmx]

I have one on my 240SX as well.

I have to say power gains are nonexistent...at least it's not enough to feel a difference.

The most noticeable difference is the brighter headlights and slightly smoother rev.

Changes depend on where you up the ground wire.
If you ground the alternator, I guess it should improve its efficiency.

"Earthing" is the latest craze in Japan.
The dealers offer it on the new Z because it sells well.
That's the only reason.