Grounding Battery for better mileage?
 

This query was generated in a round-about way, and forgive my wordiness:

I have installed heavy gauge wiring down the length of the frame of my Toyota Tacoma from the positive terminal on the battery. The objective is to supply power to a 8000 pound winch that is mounted on a receiver hitch attachment (thus making the winch removable; why carry 100lbs you need so infrequently?). In order to complete the circuit, the negative terminal from the winch is grounded to the frame in the rear of the truck, and this required me to add an additional ground wire from the battery to the engine, engine to frame....presto, a circuit that could handle the amperage load. (For the record; Project complete, all functions normally).

No conclusive data yet, as this was 4 days ago, but the truck seems to run smoother now....not that it didnt before, but I am very attentive to its behavior, and have noticed a difference.

This prompted me to imagine the possibility of an "inefficient" electrical system causing negligible resistance which would, theoretically, require the alternator to fight against the insignificant resistance.

Searching for a reputable forum with a discussion of the theory yielded nothing, but sure enough there is a site promoting a product that claims a better ground will increase fuel efficiency:

Stabilize voltage for increase fuel efficiency.

So, the question, with nothing scientific to offer at this point supporting or discounting the theory, I have to ask is: what is the possibility of an improved ground actually affecting fuel economy, and to what extent?

If your stock grounds were corroded and causing resistance, you could see a slight change. Upgraded grounding kits have shown tiny increases in horsepower on some cars, but high engine loads and high rpms is where you're drawing the most juice. IMO clean your existing grounds, use conductive grease on them and you should probably be fine. If you want to go the extra mile (and who here doesn't), throw a few extra wires between the engine and chassis. Don't spend $100 on a grounding kit that is just a pack of wire!!!

wjohnson30 -

I got that same kit on ebay for maybe $35 (my sucker limit is usually about $50, so I rolled the dice). I only used the "high capacitor" part, not the wires. My battery died last year, and I got a new battery. I didn't restore the high-cap gizmo, because I couldn't tell if it was helping.

CarloSW2

I usually increase the size of the ground wires on the car, just for posterity.

The theory is that when your ground system is creating restriction in your electrical system, you have to pull/make more amperage from the alternator to compensate for the restriction (since voltage is the constant in the system, amperage is increased to compensate), which results in more drag on the engine.

It probably fits in the "splitting hairs" category, but I do it also to help clean up the wires under the hood, so it's not a big deal for me. The wire is only about $1.00 a foot or so, from most Audiophile shops. Just replace all the double-ended grounds with something like 4g or 2g wire.

You don't have to buy the $4.00 cable lugs to bolt them on, either. You can just get 2 feet of soft copper tubing and make ends. Make sure the tubing is the tightest fit on the wire as you can get AFTER you cut the casing off the wire.