Audio Amp Installation

Common wisdom says *NEVER* bore a new hole in the firewall! I have been told it can make a 'rip' point if the car is in an accident.

Look for an unused rubber plug or pass-through, or find an existing one, and either poke a hole in the plug to pass the wire (being *REAL CAREFUL* not to damage any other wires in the bundle!!!) or heavily insulate the new wire at the point where it will pass through the fiewall and 'bypass' the plug by shoving the wire into the hole.

If you're *REALLY* paranoid about water, etc, get some black RTV, pass the wire, and goop it where the wire goes through. The rubber they use is sort of 'self-closing', so if you do poke a hole I don't think you'll have any problems.

Done this about a dozen times...works for me!

Now, in the good old days, Toyota used to make all the firewalls the same, so if you had an Automatic, there was still a hole with a plug in the FW for the clutch cylinder. My Supra has this, but a '95 Tercel I had didn't. Look to see (if you have an A/T) if there is a plug near the brake master cylinder. If you do, it's a snap!

Use a suitable fuse at the battery end of your # 8 wire.

I do, but modern amps have their own fuses as well. But it's still a good idea, especially if there is ANY chance the insulation may break down and the wiring touches bare metal!!!

With #8 wire, a 30A fuse is spec. Subs are known to blow "spec-size" fuses once in a while. You can go up to a 40A if this happens, with the amp fused itself all the batt-end fuse is doing is protecting the wire if it does short to the body. If this happens, a 40 will blow just as fast as a 30.

If you are using those 10-50 farad capacitors with your sub. you may have to go to a 60A fuse. Them puppies do suck some serious juice when charging up!

I misremembered the reason (and I do wire/fuses to the battery all the time at work... ??) there's a fuse at the battery....

IS PREVENTING UNDER-HOOD FIRES........

You mean, like AMC Eagles and Gremlins? ;)

If anyone wants to know...

I ended up using the hole the air-conditioning drip line goes through. It's located on the passenger side, and I was able to get to it from under the car. It's located about half way up the firewall, and you will see a hose about 1/2 inch in diameter hanging down with nothing connected to it. I was able to push the #8 wire between the grommet and hose very easily.

Thanks for the info!

I added to the subject line for better googability. This is something that can be used by CB'ers, ham radio operators, and others needing a way to poke that important wire .....

It can be an absolute pain to find these holes, been dere, dun dat.