I have an '04 accord dx 5 speed and cant find a hole in my firewall.. Any suggestions?

 

hmmmmm, there should be plenty of little holes in your firewall. I have an 03 and they are generally easy to spot. look for where the other wires are going and it should lead you to a hole easily.

 

first question - what size power wire?

if the wire is small enough, you can get by with routing it along with factory wiring.

sometimes you can find an unused plastic grommet cap that can be drilled out or replaced. usually above the gas pedal.

note that you need to remove the factory sound deadening material and look at the metal fire wall to see anything. make sure to replace this material when you're done.

if you can't find a grommet you can or want to use, you then locate a place on the fire wall that is free and clear on both sides, and drill a hole for a firewall grommet sized for your power wire (Streetwires makes a nice one for cheap).

 

I have an 03 coupe and the same problem. Has anybody found a good place to run a power wire through the firewall?

 

every vehicle is different. sometimes you need to drill a hole if you can't find an unused grommet.

the first step is to pull back the factory firewall sound deadening so you see metal. sometimes there are pieces of the vinyl barrier that are removable so you don't have to remove the whole thing. those pieces usually line up with passageways through.

when drilling through a firewall you need to be VERY CAREFUL so you don't damage something on the other side (obviously). i usually spend an hour on a firewall grommet for a new vehicle - making sure i've got the right spot, getting the hole the right size, using a proper waterproof grommet, etc. i'll also drill a small 1/8" pilot hole first to verify i'm in the right spot, it also helps the larger drill stay centered.

 

funny, i said the same thing twice without even realizing it.

that just goes to show how important those steps are.

 

I have yet another question regarding my audio system. This one will seem like a no brained but here we go:

I'm running a two amp system in my car which is detailed in my signature, with those two amps what size power wire would I need? I'm currently running 8 gauge wire from the battery up front to the trunk. What side effects would my system suffer with this smaller gauge of wire?

 

If you are running 8ga sharing off of 2 amps. NO! If you want to share 1 power wire to 2 amplifiers use the IASCA chart for wire guage compared to current draw. Use power wire that the amp was designed for. 8ga inputs on an amp use 8ga wire, 4ga inputs use 4ga wire and so on. Most likely your amps are 4ga inputs. If that the case then 1/0 may be the way to go unless seperate power.

 

agreed - 8awg is too small. if it is fused at 60A, then it's safe, but it also is telling as to how much power you actually draw. if you don't have a fuse, then you have a fire hazard. always fuse as close to the battery positive terminal as possible.

The most important thing about wire sizing is protection - both overcurrent and short circuit. in car audio, we use fuses for protection. AGU (round, cylindrical) are the least reliable fuses. MAXI, ANL, AFS, etc. are more reliable, and their usage depends on the size you need.

a wire sizing chart is in my signature, and is based on distance and current draw. you won't know the actual current draw of your system without measuring it, or estimating it based on impedance loads, gain settings, and volume usage. you can estimate power draw by looking at rated RMS power output of each channel based on impedance load (or based on DMM-measured gain settings). then sum the total RMS power from each channel of each amp that is expected at any time. For each amp, factor in the rated efficiency of the amplifier to determine the power draw of each amp. then apply ohm's law to determine what current is required for that power draw. this is more accurate than just adding up amp fuses, as most people aren't operating at that extreme case.

With the amps listed, and our previous conversations, 4awg fused at 125A is probably enough. If you're actually drawing more than that, then your stock electrical system will not be adequate.

1/0 power and ground wires are recommended for systems over 1000W RMS. Larger wire reduces voltage drop at the amps, and helps you to actually make rated power. Each connection is crucial, as the added resistance of the connections results in more lost voltage, and more lost power. A fused distribution block by the amps is recommended for power (unfused for ground) with those fuses sized for the wire into the amps. As recommended above, you should use wire sizes recommended by the manufacturer for their amps - 4awg or 8awg. If your amp has <60A of internal fusing, you can use 8awg.

 

I went ahead and got a length of 4 gauge wire to connect to my battery then run to the trunk. One thing is I don't know about is what kind of fuse and distribution block to use. Sounds like 125 amps is a good estimate for my "blow point" but what's the most reliable yet cheap type I should get?

Also what site online sells fuses and distribution blocks that's reliable. This town I live in does not have a local shop that sells them alone. Crazy I know.

Thanks