Dedicated Vs. Chassis

[panda 10+ year member]

my bro is going to run 5k rms at 1 ohm he has 2 runs of 0 gauge wire one for negative another for positive...

ok then since he wants to run that much amount of power what is the best option???

the 2 runs for positive power and ground to the chassis

or save alil more and get two runs of positive and two runs of negative.

what will be the diference from the two.

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[audioholic 5,000+ posts]

I dont see how an arguement can be made that dedicated runs would be worse, many times it would display less or a negligible change in resistance within the circuit. This is dependant on many things however, is it a full frame car or unibody, how well is the body and chassis isolated from each other, etc. To know for sure, use dedicated runs. With that much power on tap, Id hope your friend would be running additional batts anyway, mounted close to the amplifier(s).

The only real disadvantage I see to dedicated runs is cost, and the pita factor.

 

[DBDRAGGUY 10+ year member]

I was never a big fan of a dedicated neg run, However I always ground my batteries to multiple points on the frame.

 

[audioholic 5,000+ posts]

I was never a big fan of a dedicated neg run.

Why?

 

[Lakota 5,000+ posts]

I was never a big fan of a dedicated neg run, However I always ground my batteries to multiple points on the frame.

sarcasm?

 

[savagebee 10+ year member]

If its a body on frame car, I cant imagine how dedicated negative runs from front to back would be superior

I haven experimented with it, but I dont see how it could be worse.

Ive been rewiring my car, and plan on doing the grounding to the frame on my caprice, Ill take some measurements when I get around to it, and see If I have a measurable difference

 

[audioholic 5,000+ posts]

If its a body on frame car, I cant imagine how dedicated negative runs from front to back would be superior
I haven experimented with it, but I dont see how it could be worse.

Ive been rewiring my car, and plan on doing the grounding to the frame on my caprice, Ill take some measurements when I get around to it, and see If I have a measurable difference

Simple... mechanical joints never intended for passing current. Yes, the frame itself is one large piece of steel capable of passing large amnounts of current with very little resistance, but you also have to mount to that frame. Every break ina wire and every joint made (even soldered) adds some resistance. If you already had a dedicated ground cable back to your battery that was sufficiently large enough to produce negligible resistance, changing out to a chassis ground can't improve things... only has the possibility to be worse. Any improvement wouldn't be noticeable, the only possibly noticeable change would be negative.
The benefits of running a dedicated ground cable include known and calculatable resistance to the circuit, fewer connections to add resistance or corrode etc, and according to some people helps eliminate the possibility of induced noise into signal cables due to the entire chassis passing current through it.

So again it comes down to, the only real downsides to doing a dedicated ground cable are cost, and the pita factor.

 

[savagebee 10+ year member]

okay, thanks

but the pita factor is pretty big to me lol

how much of a measurable difference do you think there could be?

I have a large supply of very unflexible (but free) 2 ga copper.

Ive made 4 runs for battery to frame, and planned on doing the same in the back, to mount to a buss bar as a central grounding point in the rear.

I understand what you are saying about the possible noise in the signal cables, but do you think this would be a viable option?

Im planning on 4-6kwrms (at most, probably more like 3-4.5 kwrms) and thought with an overdone ground, with very short lengths of wire, I would eliminate the advantages of using the front to rear negative runs)

I figured since the ground cables are 2 ga (large 2 gauge, they measure between 0/1 and 2/0) and I have 4 runs of less than a foot to the buss bar, Id make things a little more comprable, since this cable is so unflexible it wont really work for multiple undercar/in car runs.

like you stated, its a cost-pia compromise, but I dont want to build this up, only to find out its inferior to going the other direction

I would only be out the cost of the solder and the terminals (the cable was free to me) and the time spent soldering and drilling into the frame for the self tapping screws, so its not a big deal. But, if Im wasting my time, Ill just stop and wait till i get some flexible cable

 

[audioholic 5,000+ posts]

Full frame vehicle or unibody? If full frame, definitely run your ground to that, and call it done. If its unibody, Im not sure which way id go. A few years ago I read where David Navone or Richard Clark tested the resistance of several (at the time) modern vehicles and found quite a wide range of varying resistances. I wish I still had a link to that article. Maybe I'll try to dig it up, or someone else will chime in who remembers it.

 

[savagebee 10+ year member]

full frame baby

its a 92 caprice

Id love to see tht article as well

 

[lil_italy773 10+ year member]

u always want to keep the grounds as short as poss.. i chassis ground in the back my batts and i have for extra meausre a dedicated ground back up front to the big 3 chassis ground from the neg... it will find the path with least resistance in either way.

 

[Hintzyboy 5,000+ posts]

The only way running a dedicated ground would be a pita is if you install it after the power wire. If it's a new install, there really isn't any more effort required to run two wires than there is to run a single one.

 

[savagebee 10+ year member]

except fitting it all in a cramped space, I have 2 runs of 0 ga under the carpet, and its noticable if you are looking for it, theres no way I could run 4 runs of 0 ga through the car without it being a problem, and my car is huge, Im sure its more of a problem with smaller vehicles

 

[lil_italy773 10+ year member]

except fitting it all in a cramped space, I have 2 runs of 0 ga under the carpet, and its noticable if you are looking for it, theres no way I could run 4 runs of 0 ga through the car without it being a problem, and my car is huge, Im sure its more of a problem with smaller vehicles

i ran my 3 runs of 0awg under my jimmy with a shielding around it welding wire thoe more sujectable to the elements but thats a route u can go

 

[savagebee 10+ year member]

I know, thats the route Im in the process of going //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I was just playing devils advocate, a lot of folks will not go under the vehicle, I have no issues doing it, just pointing out how that doesnt work for everyone