Car Stereos: Audio Installation, gauge wires, pioneer head unit

Question
I am new car audio installation and I need alot of help before I buy anything.

1. What amp kit (gauge wires specically) should I use for 2000 watt amp and 2K sub

2. Same question but regarding 2 sets 85W speakers/tweets with 500W amp and Pioneer head unit

3. I know I should get a better battery and/or upgrade the alternator but could you explain "the big 3"

All going in a late model Altima r Impala
Thanks in advice

Answer
Hi,

1.  Assuming the "2000 watts" is an RMS power rating, and not a "peak" or "max" rating, then you should use a 2-gauge or larger power wire.  

2.  For the 4-channel amp, an 8-gauge wire should be enough.  

In both cases, I'm assuming a power wire run of around 15 feet.  If the power wire needs to be much longer, then it might need to be thicker to avoid an unacceptable level of voltage drop.

3.  The "big 3" refers to an upgrade of three wires in the charging system: the wire from the alternator's output terminal to the positive battery post; the wire from the negative battery post to the vehicle's chassis; and the wire from the engine block to the vehicle's chassis.  

A "big 3" upgrade just means installing heavier wire runs than the stock wiring.  You don't need to remove or replace the factory wires, or route the wire the same way; you can add your new wiring in addition to what's there.  The purpose of a big 3 upgrade is to reduce voltage drops caused by undersized factory wiring (which wasn't designed to support the current draw of a high-powered audio system).  The reason that the engine block to chassis wire should be upgraded is that the alternator's ground path runs through the engine block.  

If you upgrade your alternator, a "big 3" upgrade is a must because the factory wiring is designed to support the current output of the factory alternator, not the higher output of an upgrade.  Without an alternator upgrade, a big 3 wire upgrade can be helpful, but it's not a magic bullet.  If your stock alternator can't support the current demands of your new audio system, upgrading the wiring won't help the situation.

Hope this helps!

Brian