I recently installed an 1100w amp in my 2002 Mazda protege. The wiring is 4 gauge and the amp is pushing 2 800w 12's. when I turn on my lights my amp cuts off however when I turn the dimmer all the way down with the lights on the amp turns back on but the subs sound horrible. Any suggestions as to what to do?

 

What size alternator?

 

It's the stock alternator I believe it is only 80 or 90 amps

 

an 1100 watt amp with a huge fuse is just stupid. the 4 gauge wire may not be thick enough for that power either unless it's under 10 feet long. As per chart, if your fuse on your amp (or all fuses added together) is less than 175 amps and your length is less than 10 feet then 4 gauge is ok.

Yes you will need a second alternator and probably a second battery. I avoided this issue with a 600 watt mono amp capable of going down to 2 ohm which powers my 2 15" subs and it shakes the sh.it out of my car to the point of extra spray foam insulation. However i can get away with 1 alternator. You just dug yourself in to a money pit. Due to your power requirements you need 2 alternators ($$$$$). You should also have 2 batteries, 1 for the car and 1 for your stereo with also an isolator which prevents cross draw of running devices.

You also need to run extra thick ground wires from the negative terminal on your battery to the ground body on the car. Just running a ground wire from your amp to the body is a fire hazzard------your stock ground wire will fry!

The pic is an example of a battery isolator: you run your positive wire from your alternator to the middle. From each outside pole, you run a positive wire from there to the positive terminal on your battery. 2 outside terminals = 1 for each battery. Now your headlights won't be affected by your stereo as it is drawing from a separate battery. The size of your isolator depends on the size of your alternator. The size of your alternator depends on fuse on your stereo!

 

Also, I had a 4 gauge wire almost 20 feet long when i had my amp at the back of my wagon. I had to move it up behind my front seat (less than 10 feet) to get my bass back. Also bass speakers sound better pointed towards the back than the front (if you have a large open space). Mine are right by rear hatch as you saw in previous pic.

Even though thickness may be ok for charging, it may not be thick enough for proper bass response. (as problem i was having).
So you may have to thicken and/or shorten up your wire.

 

Lol all I did was install a high output alternator and it did the trick

 

I'm not laughing. I've been through many systems and set-ups and recently experienced loss of bass due to power wire length, but i have an ear for quality sound.
Do you have a second body ground? or did you just ground your amp to body? Add a ground wire to your engine block?
Did you clean your stock ground as well?
How long is your power wire from amp to battery?
What size is your fuses on your amp?

Sounds like you are taking the cheap way out and not getting max bass from system.
Your headlights will flicker to the beat of your bass with your current set-up when bass is cranked.
Ever hear your car when your outside with bass cranked? Rattles?. This is embarrassing, not impressive.

below is Recommended Cable Size by Power and Distance from: http://www.the12volt.com/info/recwirsz.asp
Total RMS
Power (total watts) Distance
watts 4 feet -8 feet - 12 feet - 16 feet - 20 feet
100 10 gauge 10 gauge 8 gauge 8 gauge 4 gauge
200 10 gauge 8 gauge 8 gauge 4 gauge 4 gauge
400 8 gauge 8 gauge 4 gauge 4 gauge 4 gauge
600 8 gauge 4 gauge 4 gauge 4 gauge 4 gauge
800 4 gauge 4 gauge 4 gauge 2 gauge 2 gauge
1000 4 gauge 4 gauge 2 gauge 2 gauge 2 gauge
1400 4 gauge 2 gauge 2 gauge 2 gauge 2 gauge

According to above chart, power wire thickness for your amp must be 2 gauge beyond 8 feet.
Quote from site: If your measurement is between two measurements, use the higher one.

 

i installed a high output alternator and kept the same exact wiring. one ground from the amp to the chassis of the car. my trunk his insulation spray and has an aftermarket latch to hold it down tighter to prevent rattling. 4 gauge wire works fine i think you dug yourself into a money hole not me. All you have to do to prevent headlight flickering is add a capacitor i did it to mine. 2 gauge wire? seriously?

 

If you are planning on keeping the car, you will be subjective to wireing issues. Feeding 100 amp or so through factory wireing over extended time is going to cause issues.

 

This is just stupid. The wiring on cars these days are minimal and are not meant for huge aftermarket amps. Not putting an extra body ground to battery, really?----go ask a proper aftermarket stereo install place!
Again, you saw the chart for 2 gauge wiring and you still never said your power fuse size or power wire length, but i already know the answer to this due to your neglect on responding to my questions. You may think your bass is OK, but it more than likely could be better----like i said before been there done that.
Good luck, you're gonna need it!