Aftermarket amp placement and Firewall through

[Jolbaru_LGT]

So, I’m installing an aftermarket amp for a rear sub. It’s only a modest 250 watt mono amp. Anyways, what’s some of the best places to put an amp, and where can I get through the firewall cleanly to install the power to the battery post? It’s an 05 5MT LGT wagon. Thanks!

[JohnDeere714]

if you got small enough hands or are really goot at contorting yourself there is a little grommet behind the driver side fender. Not the main harness but just behind it. Thats what I tapped into for a boost reference line. Theres grommet kits you can use that allow wires to pass through if you dont want to cut a hole in it. 

[GearJamr]

I routed my wiring through the grommet in the driver side fender.  I pulled back the liner and it's pretty easy to get to from there.  You could also go through the large wiring grommet just in behind the turbo.  Depends on where you want the amp.  I got a small profile Alpine amp that I put under the driver seat.  I wanted to go passenger side but there is not much clearance there.  Depending on size, if you wanted to get really creative you could mount it to the back of one of the removable panels near the rear hatch.  Or mount it underneath the spare tire cover or on top of it.   

[NORULZleggy]

I would run the wire through the grommet on drivers side, and then install the amp off the Box so you can remove the sub. Don't do anything by that turbo.

[Jolbaru_LGT]

2 minutes ago, NORULZleggy said:

I would run the wire through the grommet on drivers side, and then install the amp off the Box so you can remove the sub. Don't do anything by that turbo.

Oh, I should have mentioned I'm installing the OEM '09 Outback HK sub.

I have the rear speaker bracket and HK 2 ohm dual voice coil subwoofer, and OEM HK speaker cover, which is going in the rear cargo area. The amp in question is a 250 watt mono amp(Alpine MRV-M250) so, it's 1 and 2 ohm stable. Now I know it's maybe not the best speaker it's attaching to, but it's easily replaceable and plug and play with a different sub. Probably that Pioneer TS-A2000LD2.. But it's no rush, I'll see if I can live with the HK. I've also got the Alpine iLX-207 HU and Alpine KTP-445A Power Pack to handle the 2 ohm 09 HK outback speakers all around.

I just have to find a nice place to hide that amp, yet still access the controls.

 

[Phillyballs79]

On 10/17/2022 at 11:11 AM, GearJamr said:

I routed my wiring through the grommet in the driver side fender.  I pulled back the liner and it's pretty easy to get to from there.  You could also go through the large wiring grommet just in behind the turbo.  Depends on where you want the amp.  I got a small profile Alpine amp that I put under the driver seat.  I wanted to go passenger side but there is not much clearance there.  Depending on size, if you wanted to get really creative you could mount it to the back of one of the removable panels near the rear hatch.  Or mount it underneath the spare tire cover or on top of it.   

Im doing the same this weekend, havnt looked for a good spot yet. is this fender grommet big enough to get a 0 gauge wire through? i bought a small 2k watt amp to drive 3 8's. was trying to keep things small, but this 'small' amp needs 1.21 gigawatts and a big 3. (dont shop on amazon while drinking) no buyers regret, its gonna be amazing but i made lots of extra work for myself..lol thanks in advance 

[Jolbaru_LGT]

7 hours ago, Phillyballs79 said:

Im doing the same this weekend, havnt looked for a good spot yet. is this fender grommet big enough to get a 0 gauge wire through? i bought a small 2k watt amp to drive 3 8's. was trying to keep things small, but this 'small' amp needs 1.21 gigawatts and a big 3. (dont shop on amazon while drinking) no buyers regret, its gonna be amazing but i made lots of extra work for myself..lol thanks in advance 

Yes, it’s big enough. I found I didn’t even need to take off the inner fender cover off all the way. I removed 3-5 clips closest to the driver and was able to get in there and see what I was doing. You also have to remove some clips and a cover by the windshield wipers. I would also have some extra fender clips ready, because mine just deteriorated and broke off. 
But you can see the rubbery part that you’ll need to poke through. There’s another bunch of wires or whatever passing through it. I poked through right above it. But I did a sloppy job. Now that I think about it, you might want to have a right angle drill attachment and a decent sized bit to get through there? I’m not sure if there’s enough room to work, because I did it the wrong way and chewed my way through, and the grommet I used doesn’t sit properly now. Oh well. Good luck though! It’s really not as hard as you think it’d be. 

Edited November 16, 2022 by Jolbaru_LGT

[Phillyballs79]

On 11/16/2022 at 9:33 AM, Jolbaru_LGT said:

Yes, it’s big enough. I found I didn’t even need to take off the inner fender cover off all the way. I removed 3-5 clips closest to the driver and was able to get in there and see what I was doing. You also have to remove some clips and a cover by the windshield wipers. I would also have some extra fender clips ready, because mine just deteriorated and broke off. 
But you can see the rubbery part that you’ll need to poke through. There’s another bunch of wires or whatever passing through it. I poked through right above it. But I did a sloppy job. Now that I think about it, you might want to have a right angle drill attachment and a decent sized bit to get through there? I’m not sure if there’s enough room to work, because I did it the wrong way and chewed my way through, and the grommet I used doesn’t sit properly now. Oh well. Good luck though! It’s really not as hard as you think it’d be. 

Thanks! So I failed at attempt #1.. First I tried the big wire loom on the passenger side, I made a small slit and fished some 14 ga thhn in. was super tight but i made it, never getting 0ga in there without possibly damaging wires in that harness. then i started scoping out the driver side footwell you suggested. there is an unused grommet with a cover that is the perfect size above the door wire boot. i tried fishing same wire through and it seems to be landing inside a void in the sheet metal. after getting my hand stuck up in there like some kind of bear trap and freezing my ass off, i threw in the towel for the day. My question to you is, behind the fender liner (which i didnt remove yet) is there a better view / path to the inside? If thats the case im sure this will be wayy easier and will be able to use a proper grommet. Im too old and slightly wiser to take chances with 150+ amps and a rub through! lol! thanks again for your help!

[Jolbaru_LGT]

21 minutes ago, Phillyballs79 said:

Thanks! So I failed at attempt #1.. First I tried the big wire loom on the passenger side, I made a small slit and fished some 14 ga thhn in. was super tight but i made it, never getting 0ga in there without possibly damaging wires in that harness. then i started scoping out the driver side footwell you suggested. there is an unused grommet with a cover that is the perfect size above the door wire boot. i tried fishing same wire through and it seems to be landing inside a void in the sheet metal. after getting my hand stuck up in there like some kind of bear trap and freezing my ass off, i threw in the towel for the day. My question to you is, behind the fender liner (which i didnt remove yet) is there a better view / path to the inside? If thats the case im sure this will be wayy easier and will be able to use a proper grommet. Im too old and slightly wiser to take chances with 150+ amps and a rub through! lol! thanks again for your help!

Yes, Um... Do you have a manual or Auto? I have a manual, but I was told if you have an automatic, there's a firewall access where the clutch master cylinder should be. If you're going the driver's side inner fender route, it's really easy. You won't know until you peel back that fender liner. But it's kinda just staring you in the face when you get to that point. Open it up and take a look, then it'll make sense. But yes, you have to remove that fender liner a bit, there's no other way around it.

Edited November 20, 2022 by Jolbaru_LGT

[GearJamr]

21 hours ago, Jolbaru_LGT said:

Yes, Um... Do you have a manual or Auto? I have a manual, but I was told if you have an automatic, there's a firewall access where the clutch master cylinder should be. If you're going the driver's side inner fender route, it's really easy. You won't know until you peel back that fender liner. But it's kinda just staring you in the face when you get to that point. Open it up and take a look, then it'll make sense. But yes, you have to remove that fender liner a bit, there's no other way around it.

I previously had a 2006 auto 2.5 wagon, and I ran my wire through the clutch grommet.  SUPER easy.  Imagine my surprise when I got a manual 2005 GT!  But yes, once you pull back the liner the grommet is pretty much staring you in the face.  And it passes into the cabin fairly high in the footwell so it's easy to route under the dash or down under the carpet along the door.  Same for if you have an auto, that one comes right out by the pedals, super easy to route from there.

[Phillyballs79]

Yeh, It’s a manual, so no extra grommets. Fender liner will be the first thing I rip into next time I get enough daylight to finally finish this. It was like 29 degrees and windy on Sunday, I restrained myself from trying to get those friction clips off the liner with numb hands. Lol, I would have broke every one of them! Thanks for the knowledge, I will post a pic  when it’s done this weekend. I’m using the indoor time to make a nice plexi amp/processor mounting rack.

[JohnDeere714]

You could always get sloppy and just run the cable out the fender and into the cabin via the doorway.