This may be a useless question...
 

With regards to the "big 3" upgrade, would this really help...

Since I only have 2 guage wire available here locally, do you guys think that leaving the current 4 guage cables intact and adding the 2 gauge cables along side them would help do the trick? I'm not worried how tacky it would look.

Just FYI, I'm not worried about future upgrades as I won't be replacing anything unless it burns out or breaks down haha.

well look at it this way, it cant hurt

I always leave the factory wiring intact when doing the big 3 and simply add the new wiring to it. I route it differently and use a few different locations then factory to keep it neat however.

Or order in the 0 gauge and do it right.... I stock it by the foot.

thanks guys for the input. MR2NR, what do you charge per foot for 0 guage?

if you go over the existing factory wiring, your new wiring will override it cause it can handle the great amount of amps going thru it. but be carfully cause the factory wiring may start to get hot and melt the insulation if your running an intense setup.

You're tight and wrong. Right on as the bigger wire will override, cause the current likes to travel through less resistance. As for factory wiring getting hot, that is way off, as there will actually be a lot less current travel there, as the current will choose to travel through the bigger wire.

Sasha your right and wrong also. Your are correct that the bigger wire will have less resistance in theory, but the difference is so small that a significant amount of current will still flow through the smaller wire. If you have enough load to require a bigger wire, then add say a 1/0 cable parallel with a 4ga the load will more or less be divided between the two wires and the 4ga may end up with too much current flowing through it (1/2 of peak load).

Running two different sizes of wire in parallel is a bad thing. Always run the same gauge wires when doing parallel runs and make them all the same length (within an inch).

Shawn76, I don't know how many 4ga wires you have running right now but if you need to upgrade put a couple 2ga or even 1/0 wires in there.

Maybe jalat, sasha, and bizkit are all right/wrong? :) hehe

Anyways thanks guys for the help. Oh and bizkit, I have 3 4ga cables running so far. 1 for amp, 1 for battery (-) to chassis, and the other for the chassis to engine. Not going to upgrade this system so I'm hoping the 4ga will be sufficient enough. Still a slight lights dimming issue when vol. is cranked... hopefully the last cable added will solve the rest.

Hooking up the alt cable is going to royally suck. Tight spot to work in. *blah*

I could be wrong... I've been wrong before... But I like my story best, and I stick to it...

Uhh typos... one 4ga wire for amp. other two cables are 2ga. Typed wrong gauges in earlier :P

I could be wrong too. but i know i had an issue with my factory ground on my car getting hot even though i had 4 gauge ground there too. so i got rid of the factory ground and its fine now. but that may only go for the ground wire.

Yes I've tried it with and without original ground. made no difference for me unfortunately.

why wouldn't 4 guage be sufficient underthe hood. the guage of the wire is determined by the current draw AND the length of the wire. check this link for more info

Recommended Power and Ground Cable Sizes

a 4 guage wire that is 4 feet long can handle 188amps of current which equals about 1400rms power. That's assuming that the amp is 50% efficient. 0 guage, or 2 guage even is over kill for the big three under the hood.

If your getting head light dimming it's because there's not enough power in your electrical system. That means the problem is your alternator as it is the real power source of the car.

Thanks for the info and link.

Based on the charts, it appears I should be upgrading the alt. to at least 172amp (1200W RMS of amplifier) from 105amp, and running 2 ga power wire to amp since length i am currently using is over 14 feet? Right now it's 4ga cable to the aq1200d. And yes it looks like 4ga cable will be suffeciant for the big 3 like you said.

If I'm wrong, feel free correcting me! :)

if your lights are dimming you should get an alternator but you don't nessarily need a 172amp alt. Remember those ratings were for a amp that operates at 50% efficiency if your amp is more efficient(which is should be if it's a D-class amp.should be upwards of 70-85% efficient) you would need less current which means smaller alternator. However it's always best to get more than you need so you can upgrade.

.... on the parallel run of cable resistance debacle... why would factory 4 or 8 gauge have more or less resistance than the additional cable? It could very well have less (probably determined by terminal connection quality)! And BTW the current would be shared by parallel runs of copper with the cable with the lowest resistance carrying the most current silly gooses.... current in a cable determines heat produced by the cable, but connection quality determines heat produced at a termination point (poor quality termination means more resistance to current flow) = more heat. AND this is why I recommend ring terminals over compression fittings.

So Shawn76... how big a cable can your amplifier accept? As far as cable size goes the sticky on this web site is pretty good for that stuff

The amp is D-Class. The efficiency @ 4ohm is 84% based of their website, but I am running it at 1ohm so I'm not sure what it would be at that amperage. Maybe roughly the same? BTW thanks for your reply back and for the help you've provided. Much appreciated.

Not sure what the biggest ga cable the amp accepts, but I do know a 2ga cable would work. MAYBE a 0/1 ga but honestly I don't know. Right now I have about 14ft of 4ga running to it from my battery. The terminal connection may be an issue.... it's using standard lead connectors.

I'll check the sticky out to... must have overlooked it. Appreciate your help this far... :)

most likely the efficiency will go down a little but not enough to really cause any problems. JohnVroom's statement about the terminal ends is the best one I've seen in a while. There's no point in using a big ol' wire if the connection at the end is chit. If I remember correctly 0ga. is quite a bit bigger than 2ga. If the holes arent big enough you should find a distrobution block that goes from 0ga to 4ga or something like that since we've already established that 4ga. is more than enough for short runs.

Good advice guys... terminals are the next thing I'll be working on.