Grounding

[Cp1]

I had a young man about 17 with a 89 turbo II visit me today as he had been experiencing a lot of electrical problems with his car. i immediately diagnosed his problem as a bad ground. sometimes his car wouldnt start other times it would just die and etc.

the negative cable wasnt bolted down properly to any where on his car and the nut on the starter was also loose.

He was amazed i guess it was something he overlooked and it got me to thinking about how many young guys may also not know what it means to have a proper ground on your car i mean its something thats general assumed that people should know. because loose/damaged wires are a hazard and can short out a circuit, burn out a fuse, or worse start a fire.

So what does proper grounding mean?

Your car as well as most cars these if not all these days are considered "negative ground" meaning that the negative side of the battery is directly attached to the chasis/motor etc. in order to complete the circuit the basically to save the shear numbers of wires you would need if each electrical component had both a positive and negative wire with a switch and fuse going back to the battery. So to simplify this the negative is attached directly to the metal on the chasis where it acts as one half of the circuit.

Proper grounding means that you have connected to this properly that is why completing circuits over painted surfaces or rust/oxidized is a bad thing. as paint and rust do not generally conduct electricity very well. a weak or intermittant circuit such as your window or headlight motors is usually caused by these problems. and starters that dont crank 100% of the time also gives a big clue that you have a grounding/ power problem.

now that being said we all want our cars and the electrical components in them to work all the time so we should understand not only that the ground is the chasis but what makes a good conductor.

The list of good conductive metals is actually very short and unfortunately cars are usually made of steel which is pretty low on the conductivity scale.

Here are the most common metals you would find on your car

As a % of conductivity of copper the list is:

Silver: 106%
Copper: 100%
Gold: 65%
Aluminum: 59%
Chromium: 55%
Steel: 3-15%

This chart simply means that of all the metals in your car the one we rely on the most is also the least effective. Most people are surprised by this list when they first see it but each metal has its own properties. and it also means that silver is by far the best conductor of electricity out there bar none! this is a fact. copper is both the standard as well as being affordable but in a bind aluminum will give you the best value for the money.

Now to make use of this to improve our cars electrical system. A lot of ground kits are available from the aftermarket that advertised themselves to be the best. but they all come at a price. the purpose of these kits is to "re-route" the ground circuit on the car with a better conductor, because electricity will always take the path of least resistance substituting with a better conductor will allow it it bypass the poorer one.

Now this is just a general example if we see that our car is made out of steel and lets say we are turning on the taillight in which the bulb is the load on the circuit the negative must travel lets say through 10 feet of steel which has 1/8 the conductivity of the positive copper wire that also means that the car itself is acting as a series load as well. the energy lost is lost to heat which actually will warm the chasis slightly. This is not a good design but it is cost effective. by installing a copper/or aluminum wire to various points on the body or engine it will effectively allow the power to take these "shortcuts" instead. thus making a more efficient circuit.

do i need a grounding kit to do this? NO

the power in your house although AC for the most part is solid copper unless you live in an older than the 60's house which would use solid aluminum wiringand it is mostly 14 to 12 gauge wire that unless its your dryer which needs an 8 gauge wire. but this is more than sufficient for what you need.

My recommendation? purchasing a 3' length of 2-4ga. stranded copper (stranded is much better as electrons actually travel on the surface of conductors) welding wire to run from an aluminum piece on the engine directly to the negative terminal on the battery. and the rest you can get away with using 12 or even 8 gauge stranded speaker wire to bridge the body of the car to the engine and from the engine to the rear of the car somewhere. this should cost you less than $40 all told and it will do better than any pre-assembled kit that you may purchase for far more money.

cp1

also a note for consideration:

Battery relocation is a popular mod in 3rd gens and generally i see kits availabe with as small wire as 2 gauge. I would not reccommend any wire for doing this that is smaller than 1ga. Stranded wire. the length needed combined with the amps required for a cold start on your car far exceed the capacity of smaller than 2ga wire. meaning that you can actually heat up the wire over the distance you would relocate to enough to start a fire. Batteries have an amazing potential to release all of thier stored energy very quickly and you do not want the cable that you use to not be able to handle that surge. Ive even seen a kit that used as small as 8 gauge wire to relocate your battery which is downright dangerous!

[need RX7]

Good post . I'm going to recheck all my grounds right now.

[Phoenix7]

great post. I will venture out to say that not to many people pay attention to grounds unless they have some sort of electrical background.

Anyone oppose this as a sticky? We kinda have A LOT of stickies but this is an important issue.

[RETed]

Originally Posted by Cp1

Here are the most common metals you would find on your car

As a % of conductivity of copper the list is:

Silver: 106%
Copper: 100%
Gold: 65%
Aluminum: 59%
Chromium: 55%
Steel: 3-15%

This chart simply means that of all the metals in your car the one we rely on the most is also the least effective. Most people are surprised by this list when they first see it but each metal has its own properties. and it also means that silver is by far the best conductor of electricity out there bar none! this is a fact. copper is both the standard as well as being affordable but in a bind aluminum will give you the best value for the money.

I'd like to see something silver in my car!

If anyone is wondering why we don't see more silver "wiring" in use...
Gold is the standard for conductors in most applications.
Why Au (gold) if Cu (copper) and Ag (silver) are better conductors?
Both Cu and Ag oxidize readily.
Copper oxide and silver oxide make very poor conductors.
So, in their pure states, yes, Cu and Ag both are superior to Au.
Once both Cu and Ag oxidize, Au becomes an obviously superior conductor.

The same goes for Al (aluminum) wiring.
Al's affinity to oxidize rapidly makes it inferior to Cu - although Cu does oxidize, Cu oxidizes at a much slower rate than Al does.


-Ted

[Cp1]

that is correct i meant to include that note in my post where i mentioned that each has its own properties. but a good insulated copper wire with a solid mounting either soldered or crimped cant be beat. Gold is just too expensive for its benefits for most people anyway.

And Di-electric grease on contacts is an excellent way to ensure a good contact as well it provides great protection from corrosion and oxidation.

[GreatShamanGT]

I think we should make a universal archive section, that contains all the good information. That way there's a general database. We have fd3s.net but it's kind of outdated and lacks pictures.......