straightlinespeed
Sometimes I pretend to be normal
So I recall something about using ground straps instead of ground cables. Can someone enlighten me as to why the straps are better to use instead of a large gauge cable (which I am currently using).
Ground Strap vs. Ground Cable
- Thread starter straightlinespeed
- Start date
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nm9stheham
Well-Known Member
Straps of woven fine wire are more flexible and will work-fatigue less.
Oklacarcollecto
Life is an experiment
This is true. I have found several ground wires on later model imports badly frayed or broken where they were attached on the firewall which was messing with the computer.
I think that's the reason (in my mind anyway) the factory installed them from the passenger head to firewall. The engine is constantly rocking, although minimally, and a wire cable could be more prone to breaking wires and eventually resulting in a poor ground.
Another member on another post mentioned that ground wires work on surface area. So a thick round ground cable is not as good as a large flat ground strap, if I understand it correctly.
Just to be certain I replaced my flimsy rotting frayed ground strap with a 0 gauge ground cable. I also just got an inch wide flat braided cable to put on the firewall to the cylinder head. I will probably go over kill and add a few more from the battery to the radiator support as well as the fender to the cylnder head near the MSD box I am installing.
I recall my dad's challenger had grounding issues and he added about four flat woven ground cables from cylnder heads to firewall, and block to fenderwell and it solved the problem.
Mike
All of the above sounds good, but here's the thing..........
just how do you equate cable size to a flat ground strap? Is it equal, better, or smaller?
"Flexing." Just how much should a ground strap have to flex? The starter cable flexes, maybe more, and it's not flat strap
So far as fine vs not so fine wire, you may be thinking of "skin effect" the so called phenomenon where AC (not DC!!) current tends to flow only on the outer parts of the conductor. This gets more pronounced as frequency of the AC increases, and is why, in such things as high power RF transmitters and amplifiers, that large flat conductors, hollow tubing, and silver plating is used
just how do you equate cable size to a flat ground strap? Is it equal, better, or smaller?
"Flexing." Just how much should a ground strap have to flex? The starter cable flexes, maybe more, and it's not flat strap
So far as fine vs not so fine wire, you may be thinking of "skin effect" the so called phenomenon where AC (not DC!!) current tends to flow only on the outer parts of the conductor. This gets more pronounced as frequency of the AC increases, and is why, in such things as high power RF transmitters and amplifiers, that large flat conductors, hollow tubing, and silver plating is used
KitCarlson
Well-Known Member
For DC, the ampacity increases with cross section of the conductor. Small wire is more flexible, but it takes more of them. The fine wire needs to be plated to provide corrosion protection. Corrosion is what leads to both mechanical failure and increase in resistance. Copper oxide is a poor conductor compared to copper. Road salt is a big enemy.
Very good point, and "protection" you pretty much get with an insulated cable
I might add that ground straps have not been used by OEMs for many, many years. "There just might be" a good reason for that
straightlinespeed
Sometimes I pretend to be normal
Very interesting discussion so far.
My biggest complaint with the strap is the fact that it corrodes and breaks. Hence why I went to a large gauge cable. Im enjoying the different thoughts and ideas as to what to use.
Like Del stated I have not seen any straps on any of the newer cars that I have worked on. So I felt safe using cables on my car. Now if I was going for a Original car I probably would had picked up a strap, but Im not worried about the originality with my car any longer, since it is far from that.
I should had started a poll with this thread to find out how many people are running what on there car.
My biggest complaint with the strap is the fact that it corrodes and breaks. Hence why I went to a large gauge cable. Im enjoying the different thoughts and ideas as to what to use.
Like Del stated I have not seen any straps on any of the newer cars that I have worked on. So I felt safe using cables on my car. Now if I was going for a Original car I probably would had picked up a strap, but Im not worried about the originality with my car any longer, since it is far from that.
I should had started a poll with this thread to find out how many people are running what on there car.
nm9stheham
Well-Known Member
Uuuuummm.....not true; my son's '03 Dakota and my '07 Ram have ground straps from firewall to engine; the Dakota has 3 or 4 total! I bet I'll find some on my '09 Challenger if I go look. And my wif'e's '93 Caravan had 1 or 2........(I am talking about braided straps not some flat copper strip, BTW..... yes, they are plated).
And the flexing on most starter cables is over a 1'-2' length; firewall to head straps that I see tend to be a lot shorter and it is the movement versus length that is critical; short lengths obviously get a lot more degrees of bending per inch.
straightlinespeed
Sometimes I pretend to be normal
6pk2goDemon was kind enough to add a poll option to this thread. Thank you!
Happy to help & I'm interested too.... :smile:
RustyRatRod
Caput villa stultus
Well HECK yeah. What do you expect of the world's greatest mod?
My vote was for both, as most cars were set that way from the factory. Cable from battery, strap from head to firewall.
I was speaking of the main NEG strap from battery....................
adriver
Blazing Apostle
Your engine (et al ) is (probably) going to grounded some how some where.
A bonding strap is a good idea.
Now whether the original engineer of your car meant that to be the primary return path or not, I have no idea. But I sort of doubt it.
Is this why you are still wondering?
http://www.forabodiesonly.com/mopar/showthread.php?t=278980&page=2
A bonding strap is a good idea.
Now whether the original engineer of your car meant that to be the primary return path or not, I have no idea. But I sort of doubt it.
Is this why you are still wondering?
http://www.forabodiesonly.com/mopar/showthread.php?t=278980&page=2
famous bob
mopar misfit
on another thot, seems to me like a motor plate would ground thru the bolts, even w/ gaskets on both sides of it. what do ya`ll think?--bob
Want to see a crowd of flat braided ground straps ? Look at a police car. They're added to hood, deck lid, doors, everywhere. I don't know if this has to do with their onboard computers, taizers, or both but it's well grounded.
straightlinespeed
Sometimes I pretend to be normal
Yes, but no. I am grounding my engine from the head to the firewall. That thread is what got me thinking about whether I should switch to a strap. Now granted Im not a electrical guru like some of you on this site, but to me as long as it has a path to ground and a good path you shouldnt have any issues at all. Im curious as to the reason they used straps, and what everyone is using in there car.
straightlinespeed
Sometimes I pretend to be normal
I suppose that makes sense since they are a more flexible for the opening and closing of those areas.
straightlinespeed
Sometimes I pretend to be normal
Shoot I hope I didnt add any confusion, if I did sorry. I intended this thread to be focused on the Engine to Firewall.
My battery Neg was grounded to the core support, when I bought my car and stripped it down, it had a very small (1/2" wide) ground strap from the engine to firewall. I felt that wasnt good enough that is why I went to the large cable
Oklacarcollecto
Life is an experiment
My early to mid 2000s model Fords are still using ground straps. Personally I have only seen cables on imports but I don't work on that many newer cars either. I am talking about the ground strap between the engine and body.
Yeah flexible is their advantage but a 3/4 wide strap at both hinges seems overkill.
nm9stheham
Well-Known Member
Yeah, seems like some discussion on different things here.
For the head to firewall, the flat braid is most common in my experience, but either works fine electrically. Flexing is the thing to consider there, since the length is ususally short. I have seen some older Jap cars with a small group of paralleled insulated wires and crimped into the same lug for a flexible ground.
For the main ground wire, the large stranded wire is the common thing. But, I have used large flat braid for that on a race car for many years with fine results. For DC and low frequency, the electrons do not care.
For the head to firewall, the flat braid is most common in my experience, but either works fine electrically. Flexing is the thing to consider there, since the length is ususally short. I have seen some older Jap cars with a small group of paralleled insulated wires and crimped into the same lug for a flexible ground.
For the main ground wire, the large stranded wire is the common thing. But, I have used large flat braid for that on a race car for many years with fine results. For DC and low frequency, the electrons do not care.
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