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Discussion Starter · #1 ·
Hey All

Anybody do stereos in here?

Short version: need to find best spot for 4awg penetration in 1st gen firewall. Anyone have any gotchas or recommended locations they'd care to share? I'd prefer to stay on the passenger side (details below).

Long version:
Overall theme of this build is to squeeze as much out of the small electrical system the first gen CR-V as possible.

I finally gotten around to building a box for my 2 - JL 10tw3s (slimline subs) and have a Rockford T750x1bd (750w mono) amp on the way.

These poor little 1st gens don't seem as if they were designed with much electrical headroom. They come with a 95A alternator (for automatic trans).
I may have the alternator rewound for more amperage if it becomes an issue but currently just trying to get some beats going. I've seen some references to some Hondas regulating the output of the alternator, not sure if that applies to the 1st gen Cr-v or not.

Anywhoo, each 10tw3 can take 400w, 800w total.
Based on box size and air velocity (and that I thought I'd be using a Alpine PDX-M6 amp originally), I designed the box around 600w of power. The Rockford T750x1bd is 75% efficient at 1ohm (at full tilt, 1082w).

That's worst case; the amp will be more efficient at lower output levels, but extrapolating from those numbers...@ 600w that is 57A of current draw from the electrical system.
That's about as much as I can comfortably pull from this piddly alternator.

To fight voltage drop (an thus efficiency losses), I'm going to try to keep the battery-to-amp power run as short as possible. Going to attempt to locate the amp under one of the front seats. As the battery is on the passenger side, if I can get through the firewall on the passenger side, I think I can keep the run to somewhere around 8-10 feet.
So, sticking with my build theme, I've constructed custom ported box based upon JL specs, I'm using a newer amp with regulated power supply, and keeping short-as-possible power run with 4awg OFC wire.

I've included some pictures of my build here. To design the box I 3d scanned the trunk area with a 1st gen Kinect and ReconstructMe and cleaned it up in Meshmixer. Then imported that .skp into sketchup and constructed the box from there based upon WinISD parameters. My goal was to keep it as thin (depth-wise) as possible while staying within volume limitations of the 10tw3.

Any thoughts or recommendations are appreciated!
 

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Discussion Starter · #2 ·
Adding pictures here

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initial scan with ReconstructMe

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Cleaned up in Meshmixer
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Imported into sketchup
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Initial Shape
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prototype
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finalize dimensions and porting
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138610
 

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Discussion Starter · #3 ·
138611

test fit

138612

Back and sides glued. Test fitting top and braces.

138613

All glued up

138614

sub-par upholstery work

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secured by turnbuckles to the tie-downs
 

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'07 CR-V EX-L AWD
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Welcome to the forum! A key part of this, electrically, is going to be a bigger battery. I'm going with a Group 24F in my '07. There are plenty of battery upgrade threads here to help with that. The little lawnmower-sized Group 51R is woefully inadequate. Keep us up on your build! Looking good!
 

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Discussion Starter · #6 · (Edited)
Apologies for the delay, been busy lately.
I did finish my install a couple days ago, it sounds great. Here is the imgur album, or I'll attach some pictures below.

Found the best place to penetrate the firewall is a grommet located just underneath the battery tray. Remove battery, remove fuse box bolts and shift out of the way, remove battery tray and grommet access is pretty straightforward.

After that, I used a circular punch made for eyelets in order to make a circular hole and the 4awg went through with a fish, no problems.

Running the wires inside the cabin is pretty easy, just shove a fish under the carpet wherever.
Removing the trim pieces around the doors is sort of a pain as you need to remove the front passenger seatbelt bolt and B-pillar trim, but not a huge deal in the grand scheme.

It was a chore to get a speaker lead from under the passenger seat to the rear of the vehicle but I managed to sneak it in underneath the rear seat somehow.

kloker, in relation to the battery comments, I thought it'd be an issue but these newer Rockford amps are super efficient (I went with the T750X1bd).
I was worried about headlight dimming and the like, but I've experienced none of that running 750w at 1Ω.
I have a 80A fuse at the battery and a 60A fuse at the distro block (not necessary, just what I had) and the 60A fuse has not popped.
That is a cheapo O'Reilly battery...if it goes kaput, so be it. Hopefully it happens within 2 years so I can warranty it, heh.

Hope to install a voltage display soon so I might get a better idea of how hard I'm stressing the little alternator.
Not shown is an upgraded ground cable from battery-to-frame, 4AWG.

Anyway, I picked up some A-pillars from a junkyard to do a test run of some fiberglass tweeter pods sometime, probably in the fall.
End all goal is to add amped front components + DSP but that'll be a bit off in the future :)
 

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Discussion Starter · #7 ·
138930

Battery removed

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Battery tray removed, exposing the grommet

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Grommet close up

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Grommet penetration

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Close up

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All finished and put back together. Fuse on the left.


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Seat removed for amp install

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Holy cow this thing is small! (Rockford T750X1bd)

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Small amp is small

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Test fitting under the seat
 

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Discussion Starter · #8 ·
138948

Test fitting ideas

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Small amp 'rack'

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More test fitting

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Paint 'er up (mostly just in case of water ingress to the under-seat area)

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test fitting some more

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Wiring it in, setting levels etc

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Mostly buttoned up!

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Bonus sub wiring pic
 

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'07 CR-V EX-L AWD
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Wow - that little amp puts out 750 watts? Hmmm. Clean install, but I think I'd fix some sort of cover plate over it to prevent damage from back seat feet. Looking good so far.
 
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