Rewiring the "Big 3"

[kimokalihi]

My engine is somewhat apart again and while I have easy access to everything I would like to upgrade/replace my power and ground wires under the hood. The power wires are too short to reach my new optima anyways so now is the perfect opportunity. I did this on my 89 toyota pickup truck and it made a drastic difference with my dimming problem while using my stereo and amps. It was dimming badly and after upgrading the corroded and small gauge power and grounds the dimming problem vanished completely. I've also done it in my metro which only has something like 45amp alternator and there's no dimming problems whatsoever.

Before I used 4gauge amp wiring cable. It can be expensive and I'm not sure it's the optimal type of cable to use for this sort of application. It did work very well though and still working today.

What kind of cable have you guys used and which is best? Where did you buy it and how much did it cost? I've heard a lot of people buy cable from welding supply stores. Is that cable flexible enough? It's gotta be able to bend around things and stand up to the element.

[Legacy777]

I would recommend using stereo power/ground wire. It's much more flexible and easier to route and use. I went with the cheap wire initially a couple years back and ended up replacing it.

I used generic 8 gauge stereo wire and ran a lead to the alternator from the pos lead on the battery. Then ran another 8 gauge lead from the neg of battery to the starter and the chassis. I also ran a 10 gauge ground lead from the neg of battery to the ground point on the intake manifold. This is where the ECU and all the sensors ground to. This is an important ground spot. I had found that there was a difference in potential between that ground spot and the negative side of the battery. This is what led me to add that additional ground lead.

[kimokalihi]

I forgot to mention on my metro I and the toyota I added extra body grounds in a couple different locations and I replaced every ground and power cable coming off the battery and from the body to the block.

So you only used 8 gauge? I went with 4 gauge. Are you running an amp?

[PhyrraM]

Welding cable and basic amp cable (not very high end) basically only differ in jacket construction. Welding cable is also pretty flexable and usually has a very durable, heat and abrasion resistant jacket. But you will find the price is close to decent amp cable.

Good, solid, corrosion-free crimps and connectons are far more important than the size. If everything is 100% the factory size is more than sufficient. Of course, going a size or two up won't hurt.

Don't go too big-- in the unlikely event of a short, a large unfused cable can do alot of damage before something melts away and opens the short. The factory cable size is a carefully thought out comprimise between "big" enough to do the job, and "small" enough to melt away (like a fuse) in a short circuit situation (i.e. an accident).

[Legacy777]

Yeah...8 gauge should be plenty good.