I'm in the process of doing the big 3 in my '99 Grand Am; problem is, I only have 2 ring terminals to work with right now.

Question: If I do the run from my alt to the battery with 1/0 and leave the grounds with the OEM cables until the rest of my terminals come in, will that cause any issues? The current flow to my battery will be improved, but the grounds from the battery to chassis, and engine to chassis will be the same as before. Will this be ok, or should I just wait til I get all my terminals in to do the entire upgrade at once?

Thanks in advance

You will be fine just upgrade the other connections when you get the terminals.

I'm not an expert, at all, but I noticed a better voltage when I upgraded the wire from batt to ground.

when I added a bigger wire to ground the engine block, my voltage did not went up, but I had less voltage drops.

I still need to add a wire for alt to batt (+). This one was very helpful for a friend of mine : he runs +4000 rms on a 120 amp alt (stock was 60) with no voltage drops when driving (stays at 14.4 - 14.6 v !!!). At iddle it can go down to 12.something at full tilt for a few moments.

Good luck !

I'm not an expert, at all, but I noticed a better voltage when I upgraded the wire from batt to ground.

when I added a bigger wire to ground the engine block, my voltage did not went up, but I had less voltage drops.

I still need to add a wire for alt to batt (+). This one was very helpful for a friend of mine : he runs +4000 rms on a 120 amp alt (stock was 60) with no voltage drops when driving (stays at 14.4 - 14.6 v !!!). At iddle it can go down to 12.something at full tilt for a few moments.

Good luck !

I don't believe that... 120amp alt isn't going to produce ~285amps to an amp that's not very efficient in terms of power output...

Even if you had a huge battery bank, voltage would drop to batteries resting voltage (12v-13v), unless it's a 16v setup with a ton of stepdowns for stock electrical.

You have to pull the skin voltage off the battery to get to resting voltage. How much current that takes depends on the battery.

The real answer there though is that the guy isn't getting 4kW for any length of time or likely at all. Music is very dynamic and you're usually looking at 10dB or so of dynamics which means that 4kw max averages out to around 400w for real.

If you could only do one right now I would actually do the ground first. am also a firm believer of 0 GA wire or thicker