This is a long post with a lot of pictures.
After burning up the original factory size subwoofer it was time for an alternative.
The research I've done on this is extensive and has been going on for more than a year.
I never noticed that some had a post here of an under dash subwoofer enclosure ten years ago.
Nevertheless this is what I made and the continuation of that project that is still under way.



Her is where I started.


When I bought this factory box on eBay it had a pyle woofer in it. I blew it up easily.
Then I bought a Kicker woofer at Walmart. It was a joke. I took that back.



I was looking at the space around the factory box and noticed a large amount of wasted space I could occupy with a larger box.

I just have remove and relocate this relay/chime box mount to do it.


I bought a Scar Audio 6.5" to get an idea of what needed to be done.
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The little Tang Band subwoofer. For it's size it does really well.

The Scar 6.5" is just a bit too large. Time for a new box.

I started with shaping one from polyurethane hard foam.




After hard surfacing the plug it's time to make a mold.
This isn't the best way but I was learning.


[img]http://images.fieroforum.com/userimages/Caj un%2520Road%2520Warrior/IMG_20200519_095231450_HDR.jpg[/img]

Testing the fitment of the Scar subwoofer.

Lesson learned here. DO NOT use any kind of paint to coat a mold surface. The chemicals of fiberglass resin will delaminate paint.


First box is beginning.


It's ugly but at the time I was just considering only making one.

Comparing to the original plug.

Test fitting the Scar subwoofer. I still have a lot of work to do before it's ready for install.

Comparing factory box to mine. There's quite a difference.

First time in the car. This is the Scar 6.5" it perfored pretty well but I had to be careful how much to push it. It bottomed out pretty easy. However the bass was AWESOME! Way more than I expected.


This is what I did for amps. One Amper Audio 250 watt amp and one 800 single channel amp. Because the 10" head unit has no massive box behind it I used that space for amps.


This is where the fun happens testing subwoofers and porting.
From left to right: Tang Band, Scar, Rockville, and Amper Audio.


Amper Audio performed the best. It had the most excursion and the loudest sound output.
I got a 110 decibels at 34hz ported and about a 101 sealed.


This is where I started improving my mold. I had to strip out all the paint and apply tooling gelcoat.
While I was at I made a delrin insert to better protect the subwoofer. No one makes a cover for the 6.75" subwoofer.



Box number 2



Nice tight fit.

Bond the two parts and clean up the seam.


All done?


Not even close.

After many talks with other enthusiasts it seams bigger as far as diameter so I started modifying my second box turning it into a plug for a new mold.
I can still use my old mold so I may make a few boxes from it.
The goal is to fit any 8" subwoofer and the Kicker Solo beric.



This is where I was two weeks ago. I'm done shaping and sanding. Now it's ready for gelcoat. After that it's smoothing and polishing.

Then the next step is making mold #2.



Latest pics. Just waiting on warmer weather for gelcoat. The little notch at the right side corner is made to clear a relay on some models.





For comparison.

Scar 6.5"


Kicker 8" Round.


Kicker Solo beric

[This message has been edited by Cajun Road Warrior (edited 01-15-2021).]