Best Way To Get Wires Through Firewall?
 

Hey guys, metra kit came today and i've been putting my new stuff in my car :D

Anyways, my question is what do you guys think is the best way to get the wire from the battery to the amp inn the trunk? I figured it'd be easy with this car since theres a center console the whole way through and I could just run it inside of that but I can't find any good places to get through the firewall (without and drilling). Every other car i've ever installed just had like, a hole or a rubber gromet i just popped out and managed to fish the wire into the vehicle. Either that or put it up on ramps and go under it.

I've searched alot on the forum and can't really find anything definitive except that maybe somewhere behind the washer fluid bottle?

Drilling behind the fluid washer bottle is the way to go. You can also try the grommet that is on the drivers side but I really think that is more of a hassle, it's easier just to drill, stick a coat hanger down from the engine bay until it hits the floor of the passenger seat then pull the power wire back through. There are some good pics in one of the DIY threads about running amp power.

edit - then run the wire along the passenger side and up behind the back seat. You'll have to remove a couple of panels and the rear set.

I went through the main wiring harness grommet. It was a bit nervewracking but it's the only place that will let you fit very thick wires through the firewall without taking a drill to the car.

What gauge did you use Socket? I'm guessing the main grommet would be too tight for guys running 4 gauge wire.

i dont know how big 4 gauge is, but you should be able to create a fair amount of room through there. tough to cut, but should be able to

you could always run it underneath the car

4 gauge is pretty fat like the width of a penny. If you decide to drill just take it slowly and stop right after you get through the firewall! Make sure you leave enough room for your cable's grommet too. I just like the drilling method because you don't have to stick you head up against the pedals to cut the grommet.

I have a single run of 4 gauge tunning through the main wiring grommet. You cant see it when you look at it from the side of the car, but there is actually a very large space below where the the grommet is molded to the wiring harness. if you take a pen knife to that and cut a slit into it, you'd probably have enough space to run two 0 gauge wires through it.

Having done it now, I'd reccomend cutting the slit from the inside of the car, while angling the blade downwards in order to avoid nicking the wiring harness. Some of the howto's here said "shove a screwdriver through it" I tried that, and ended up having the tip of the screwdriver come up in the middle of the wiring harness!:eek::Eyecrazy::banghead:

Thank god it didn't damage any wires. I've got a photo of my wire coming into the passenger compartment somewhere, I'll dig it up for you guys to see what i mean. If you do this, spend some time feeling around there with your fingers so you can get some idea of how much space is there.

You can see here the power cable runs just below the part of the grommet that's form fitted to the wiring harness.
http://isomerica.net/~fluffy/Ren/renpower2.jpg
In this shot you can see where it comes through the other side. I used a bit of cooking oil to lubricate the cable for easier insertion. :ky:
http://isomerica.net/~fluffy/Ren/renpower3.jpg

I drilled behind the washer fluid bottle for my 4g wire. Used a dime a dozen plastic grommet. Easy. Quick. Safe. Completely hidden.

There's already a hole between the washer fluid tank and the passenger side fender. It's just hidden with tape that is stuck from the inside and painted the same color as the body. The hole is an oval. All you need to do is poke a hole in the tape, put a rubber grommet in it, put some dish soap on your wire and then run it through.
I wouldn't use oil or WD-40, they attract dirt and won't dry up like dish soap. Next time I'm going to try KY since it's water-based.

BTW, from that hole the wire comes out behind the passenger kick panel, which you'll need to remove. But that's easy.

Socket 7's pictures are EXACTLY how i ran my 4 ga. through. It took like an hour just to get that f***er through; I ended up using the clothes hanger technique. Another easy way is to start from the inside of the car and push the wire under the grommet and through the firewall. Any more than 4 ga. and you will have to drill.

Good luck with the install and get some pics up when you're done

Thats the way I went too - I tried the big grommet, but my hands were way too big to get anywhere near that - I have the cuts on my wrists to prove it!

Also, my big grommet was filled with a solid glue like material - and with all those tiny wires there I didnt want to risk damage, so drilling a 10mm hole and sticking a new 10p rubber seal was the way to go - just be careful when drilling so you dont drill into the heatting unit (I think thats what it is - large white plastic box under the glove box).

I ran through the main grommet and I'm using 1/0 gauge. There is plenty of room.

:shocking: pics of this?

I have 4 gauge running through the main grommet like Socket7, but for both power as well as a return ground to battery. Took better part of the afternoon and lots of blood sweat and tears, but two 4 gauges will fit through. Damn, I wish I had thought of the cooking oil though!

Watch what you guys spread on your wires. Some petroleum based oils will degrade the integrity of the wire's insulation. I would just try using a little water.

4 ga. stinger wire ran through main harness giant rubber thing very easily. poked a hole with a small screw driver, then stuck in a larger screwdriver... used a razor to cut the parts away that stretched out and repeated 2x. then the wire went right through snuggly :)

Laying in the trunk awaiting capacitor, blocks, and amps (still need cap if anyones got one they want to part with)

There is a perfectly sized hole behind the windshield washer bottle for 4 gauge.

As requested.

https://www.rx8club.com/attachment.p...4&d=1237747447

https://www.rx8club.com/attachment.p...5&d=1237747447

Exactly the same thing I did with my 4 gauge wire! took a little while but I rather not drill

also make a nice water tight seal! no need for extra parts!

wiring
 

Good thread... glad you guys tackled this already. Was hoping I could avoid drilling. Thanks for showing me the easiest way to do this. :)

ya its a hassle goin through the grommet but i have two strobe and my amp power cord ran through there...

Wrong!!!! IZZYRX8's (formerly my set up) is running 0/1, or 0/2 Rockford Fosgate Cables

+1.....Izzys (formerly my set up)




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