Amp Wire Through Firewall?

[DiGiornoRisingCrust]

Before I get an amp for my speakers I figured I’d find out how I’m gonna install it, but I’m having trouble finding a firewall grommet. I used the search feature, but I couldn’t find any of the grommets they listed and the grommets I did find were so hard to reach that I couldn’t possibly use them.

sorry for the repeat thread, but I’m hoping somebody can provide pics of how they did it. Thanks!

 

[MotorCityFats13]

been there tried that.... I used the floor drain plug under your left foot

i dont know what size wire you are going to be running but that hole easily fits 4awg and possibly 1/0awg

 

[DiGiornoRisingCrust]

So I found the drain plug, and poked some string through to see where it would end up, and from what I found, poking it towards the front resulted in the string going right over the cat, which is not good, and poking it towards the rear of the car made it pop out behind a body mount. The actual spot where the wire exits the cabin is hidden, and I’m a little worried that the wire will either mess something or get messed up if I poke it towards the rear.

Sorry if that’s a little vague or hard to understand, and thanks for the help! The floor plug is definitely the top option.

 

[bobditts]

Tip for ANY vehicle.....follow the stock wiring. There is a gromit that leads to the engine bay on the left side under the dash where your foot rests. NEVER drill holes if you dont have to.

 

[With_him]

So I found the drain plug, and poked some string through to see where it would end up, and from what I found, poking it towards the front resulted in the string going right over the cat, which is not good, and poking it towards the rear of the car made it pop out behind a body mount. The actual spot where the wire exits the cabin is hidden, and I’m a little worried that the wire will either mess something or get messed up if I poke it towards the rear.

Sorry if that’s a little vague or hard to understand, and thanks for the help! The floor plug is definitely the top option.

Image of where you went through I am looking to do the same thing soon.

 

[corkey]

i ran 4 gauge through the firewall in the grommet for the brake pushrod,, it`s fairly big, and comes out under/behind the booster, and than routing up to the battery was easy,,
i ran the cable from inside to outside, it was easier that way,,

 

[DiGiornoRisingCrust]

Image of where you went through I am looking to do the same thing soon.

It’s pretty simple, I just cut a hole in the grommet and ran the wire through. There’s what appears to be a hollow cavity in between the top and bottom layer of floor, and the bottom layer doesn’t have a grommet where the hole is, so make sure to protect the wire from rubbing against the metal. I used a loom and then for added security, I wrapped the part that would be contacting the metal hole in foam tape.

the carpet is already pretty thick, and I have rubber floor mats so I wasn’t worried about the wire causing a bump in the floor, but I’d definitely make sure to get a high quality, flexible power wire to ease with the bending after it exits the grommet. I’m using crutchfields 8awg kit and it works just fine.

the little blue wire is the remote turn on wire, it fell out of the speaker wire loom I had it in so I just wrapped it around the power wire until I have time to clean it up

 

[MotorCityFats13]

It’s pretty simple, I just cut a hole in the grommet and ran the wire through. There’s what appears to be a hollow cavity in between the top and bottom layer of floor, and the bottom layer doesn’t have a grommet where the hole is, so make sure to protect the wire from rubbing against the metal. I used a loom and then for added security, I wrapped the part that would be contacting the metal hole in foam tape.

the carpet is already pretty thick, and I have rubber floor mats so I wasn’t worried about the wire causing a bump in the floor, but I’d definitely make sure to get a high quality, flexible power wire to ease with the bending after it exits the grommet. I’m using crutchfields 8awg kit and it works just fine.

the little blue wire is the remote turn on wire, it fell out of the speaker wire loom I had it in so I just wrapped it around the power wire until I have time to clean it up

View attachment 177279

i used the large oval plug when I ran my over sized 4awg I didnt even notice the small plug.... depending on where you put the amp the run can get quite long and its good to just avoid 8awg unless you are only pushing a couple hundred watts

 

[DiGiornoRisingCrust]

i used the large oval plug when I ran my over sized 4awg I didnt even notice the small plug.... depending on where you put the amp the run can get quite long and its good to just avoid 8awg unless you are only pushing a couple hundred watts

Wow, I saw the big oval plug but didn’t even think to try pulling it off. I’m loving the new setup, but it’s definitely exposed the weak stock subwoofer, which will need to go. I’m looking to get a separate mono amp and a 12” sub, so I’ll most likely have to update my main power wire before the distributor to 2 or even 1 awg, so I might switch over to the oval plug for better fitment.

as long as you’re here, how do I calculate what size of fuze to use on the main power run? My 4 channel is rated for a 40 amp fuse which will be installed on the 8 awg going from the distributor to the amp. If my subwoofer amp needs a 50 amp fuse in between it and the distributor, do I just add them and use a 90 amp fuse right after the battery?

one more thing: do you have any subwoofer recommendations? I’m currently looking at an infinity kappa, JBL W3, or a sundown SA. Most likely a 12”. I understand that the SA is spl oriented, the infinity is sq, and the JL should be somewhere in the middle. But having never really heard a quality aftermarket sub in a car, I don’t really know what the difference would be between the sundown and the infinity. Both of them would probably be better than stock, but I’m not sure how drastic the difference is.

 

[MotorCityFats13]

you size the fuse based on the wire but a good rule of thumb is start with 80 amp which will pop if you pinch a wire... i have always used a 100 amp and never popped it while playing music and easily protects the car from a fire

before picking a brand of sub figure out the end goal and space you are willing to sacrifice for the enclosure and amp placement the secret to bass is the enclosure and pretty much anything will be night and day when compared to the stock unit and i dont suggest replacing the stock sub inside the plastic factory enclosure

you can do some pretty insane things these days with 8" subs and now those new 6.5" subs although you need a few more of them but enclosure size will still be smaller

 

[DiGiornoRisingCrust]

Ok thanks, I actually found a 12” JL Audio W6 in JL’s high-output box with a JL 500/1 amp on Facebook marketplace for $500, which seems like a good deal (I’ll have to test it first). To my understanding JL’s box is ported, so I’m thinking I’ll keep that box for now, and if I want to I’ll build a sealed box later.

unfortunately the ‘Ex is in the shop for a bad transmission, and I’m currently trying to decide if it’s worth fixing. I bought it 2 years ago with 146k, the timing chains broke last year which I fixed for 3.6k, and now the transmission is gone which is gonna be another 4. It also needs new tires and bearings soon which will be around 1k, and the rear axle seal is leaking. Currently looking at a Nissan Pathfinder. I would think about a 4th gen with a V8 but none are ever for sale. It sucks but I really need a reliable car right now.

so it’s TBD if my plans for the ‘sploders stereo will ever be finished