Installing your Amplifier

Installing your own amplifier:
This howto is mostly complete. I have photos that will be uploaded soon.

Start with a quality amp wiring kit available from Strathfields or tonkins. Make sure the wattage rating is equal or preferably greater than the wattage of your amp. These are expensive but do represent good value. Unless you really know what you are doing, do not skimp this step. If you do really know what you are doing, then you would not be reading this how to anyway!

Mounting:

WARNING:
Do NOT mount your amp upside down! When amps get hot, heat rises. You do not want the heat rising upwards from your power transistors because the heat rises upwards into the solder. I have heard of cases of power transistors in amps literally desoldering themselves. A well built amp should not do this, but placing amps upside down is not recommended.

There are two main places to mount the amp in an s13. On the right side of the boot (or immediately behind a back seat) or under the front drivers or passengers seat. The boot is best for cooling as you will get maximum airflow happening. If bolting it into the boot floor, be careful of the location of the fuel tank. If you are not sure of how to determine where the fuel tank is, get a professional or someone who knows what they are doing to do this install for you. I suggest in obtaining security screw to mount the amp. Security screws are like standard screws but have a different head and require a tool other than a screw driver to remove them. This will not prevent theft, but it will delay the casual thief.
Because my amp would not fit under a seat, I will describe how to mount it into the boot. Mounting underneath the seat can be a good preventative security measure as if done correctly, removal of the seat may be necessary to be able to remove the amp, this will make the amp too difficult to remove for the casual thief.

Power:
You need at least 4 or 6 gauge wiring. Big stuff approximately the thickness of your thumb. It comes as part of the amplifier wiring kit. Ask when you buy it, what wattage it will support.
The power cable must have an in line fuse close to the battery, failure to do this can result in fire! I have seen this happen.

(Pic 1 - In-line Fuse)
Do not connect the cable to the battery yet. Run the cable down the inside of the quarter panel, across the back of the engine bay along the firewall, as far away from the engine and hot components (such as turbo and exhaust) as possible.

(Pic 2 - Engine bay wiring)

(Pic 3 - Through firewall)

The hardest part is getting it through the firewall. Find a grommet in the firewall that has a cable going through it and push your power cable through there. I found a good one on the passenger side of the firewall that came out behind the glove box. I then ran the cable below the computer (remove the left kick panel to do this) and down the side of the car underneath the trim that rests underneath the door. It then goes underneath the back seat. To remove the back seat, there are two black tabs, poking out underneath the seat. Pull the right tab forward, and lift gently on the seat. Do the same with the left side and the base of the seat will be unclipped and able to be lifted out to remove it. Run the cable to the boot by running it up underneath the backrest of the rear seat. Run this to the amp and wire it up.

Ground:
The ground wire is just as import as the power wire. 90% of car electrical problems are caused by insufficient / incorrect grounding. I connected my ground wire to the child safety seat mounts. Any bolt that is bolted to the chassis will be sufficient. Ensure that there is no paint between the ground cable and the bolt. An o-ring connector on the end of the ground cable will give a better connection than stripped wire.

Signal:
If your using the stock head unit, or a unit with out RCA connectors, you will need impedance converters unless your amp has this built in. If your amp has them built in, just take the wires from the rear speakers and extend them to connect to your low impedance (speaker input) connectors of your amp. This is not ideal, but it will work reasonably well.

(Pic 4 - Console and head unit screws)

RCA connectors are the preferred approach. Remove the gearnob by unscrewing it anti clockwise. Then remove the surround around the gearstick and radio console. This unclips by the base of the gearstick and simply pulls out. Remove your centre console. This is held in by 6 screws. Two are on the side of the console the drivers and passengers front seat bolster cushions. Two are in front of the gear stick on top of the console, and two are on the sides of the console approximately level with the gearstick. Once all undone, it simply lifts up from the floor. Remove the connectors for the ashtray light and put the console out of the way. Four screws are visible on the bracket around the stereo. Undo all of these. (You may wish to replace these screws with security screws as well.) The stereo will slide out. Plug your RCA signal cable into the RCA out ports of your head unit. You also need the remote turn on wire. Find your head unit manual to connect the turn on wire provided with your amp wiring kit to the required power on wire.

(Pic 5 - Rear console bracket)

Run the two cables (RCA and amp remote turn-on) down the middle of the console section, around the gearstick and underneath the rear console support bracket. Run the cable underneath the carpet, to underneath the back seat. Keep the RCA wires well away from the power cable. The power cable will induce noise into the RCA cables and this is to be avoided. The wires will go underneath the back seat to the amp. Plug them into the amp. If you have 4 RCA inputs on your and, and only two RCA outs from your head unit use a couple of RCA y-splitters to give you 4 RCA connectors for your amp.
Wire your speakers into the amp. This is fairly straight forward. Ensure that positive goes to positive etc. Speakers will work when wired backwards but not as well, and it may shorten their life depending on their design. I will let you work out the best way to get your cables there.
Put everything back, ensuring that all cables and wires are laying flat and are not crimped by any seating or panels.

The last thing you do is connect the power cable to the battery and connect the fuse. Turn your stereo on and listen to some beats.

thanks to sr180 nissansilvia.com