Negative battery cable size?

[jws555]

Wow if disconnecting the cable gave me a 19% fuel economy increase I think I’d drive around with it disconnected all the time.

NO! NO! NO! Disconnect both cables and get a 38% boost!

Regards,
John

 

[ka9mnx]

Agreed, the ignition module will be grounded to the engine block which is also the alternator's ground. That's as good a zero reference as you can get. (Yes I know there are some ECMs that control alternators that are grounded to firewalls.)

I once had to run a #10 ground wire from the alternator to the battery. That was to eliminate RFI (alternator whine). I know it created a ground loop bit it worked.

 

[JHZR2]

Some grounds from engine to frame are also to prevent aluminum erosion caused by galvanic reaction. Wide tinned braided straps work best. Ground straps from firewall to engine and hood are also best with tinned braided and can help with AM radio interference noise.

Have a good source for these?

 

[f355spider]

I find that hard to swallow.

I get it...and obviously it was on one specific car. One cannot correlate that improvement to another car. Perhaps this specific car had a grounding problem?
A quick google search and I found a reference to the article...it was a Nissan 350Z and it was in the July 2003 Turbo magazine

Finally: Ground Kit Dyno Results! - MY350Z.COM - Nissan 350Z and 370Z Forum Discussion

Engine & Drivetrain - Finally: Ground Kit Dyno Results! - Hey all! I know a number of you have installed earthing kits, custom or otherwise. I also know it makes about zero sense to do before and after dynos because the dyno test costs more than the ground kit in most cases!! The nice folks at...

my350z.com

The original poster says 3.8hp gain, then the subsequent poster says it was a 4.8hp gain....

 

[brianl703]

Have a good source for these?

Digi-Key has a selection:

https://www.digikey.com/en/products/filter/grounding-braid-straps/494

You can also buy it in rolls with eyelets every foot, 6 AWG equivalent. Often used in telco and data center grounding applications. But I don't see that particular product right now.

EDIT: Del City also has a selection:

Braided Ground Straps - Lug to Lug

This 4 gauge ground cable is cut to length and is terminated with a copper terminal and lug. Copper wire strands are tinned for corrosion resistance and maximum conductivity.

www.delcity.net

I've purchased from both companies before.

 

[Hall]

A quick google search and I found a reference to the article...it was a Nissan 350Z and it was in the July 2003 Turbo magazine

Nissan and Infinitis from the 2000s were known to have less-than-optimal grounding and there are a lot of "kits" sold. They aren't for MPG or HP improvements though, but obscure things like slow/delayed shifts, especially when using the manual mode (either with the "tiptronic" type shifter or paddle shifters).

https://www.z1motorsports.com/boost-controller/stillen/stillen-350z-g35-grounding-kit-p-8252.html?list_name=SearchResults&oid=8252%3A0%3A82987%3A10&qid=d295d70477d30ff82459e6d8653ec76e

 

[kschachn]

I find that hard to swallow.

Reminds me of the advertisements back in the 80s for “premium” line cords for your stereo equipment. They promised all sorts of audio improvements.

 

[ka9mnx]

Reminds me of the advertisements back in the 80s for “premium” line cords for your stereo equipment. They promised all sorts of audio improvements.

They are still pushing "monster" and "gold plated" audio cables. You can get them in HDMI too!