This is a DIY for adding an aftermarket subwoofer and maintaining the stock look of the Infinity enclosure. I would not recommend using the stock amp for an aftermarket sub, as it only puts out something like 40 watts to the sub. I chose a Kicker CompVR, and it’s pretty damn impressive for an 8” sub in a plastic enclosure. If you need wiring help see my Infinity wiring diagram.
Materials:
-Dremel with cutting blades & sanding wheel, or some other small saw & sandpaper
-Silicone
-Flathead & phillips screwdriver
-10mm socket with extension

01. Remove the stock subwoofer enclosure from the hatch (3 bolts).




02. Take apart enclosure. The front carpet cover should pull right off. Use a flathead screwdriver to pop off the grill. Use the 10mm socket with extension for the bolt going through the back of the enclosure into the back of the sub. Then a phillips head for the screws securing the front of the sub.




03. Remove the stock wiring and run your wire through the stock grommet





04. Compare the mounting depth of the stock sub to the aftermarket one and make a note of how much additional mounting depth the new one requires.




05. Use your dremel with a cutting blade to cut the plastic tube that sticks into the enclosure, about 2-3 inches in from the base, or however deep you need for your sub’s mounting depth. If you have a sub with the same or smaller mounting depth than the stock sub, which is unlikely because it’s extremely shallow, you can skip this and the next few steps (just make sure you seal the bolt hole with silicone).





06. Now use the dremel’s sanding attachment to shave off the edges sticking out from the cone you just cut out.




07. Cut the cone down so it is just long enough to fill in the open tube left in the enclosure.




08. Insert the tip into the enclosure from the back, checking for a snug fit. Make adjustments if necessary with the dremel and then proceed to glue it in place.






09. Use silicone on the cut area from front and back to ensure an airtight seal. Don’t be afraid to use too much, it needs to be 100% airtight, and you won’t see this area. So slather it on. Make sure to get the small hole in the middle from the bolt and around the wire grommet as well.





09. Stuff the enclosure with polyfill if you like, it’s just a trick to make the sub act as though the enclosure is larger, then wire up your sub and put it in place. Screw it in around the edges.




10. Most likely the surround of the aftermarket sub would hit the stock Infinity grill, so it is unusable. Put the carpet cover back on the enclosure, and you’re all set. I put a ring of grey felt around the sub to match my amp, and used an aftermarket Kicker grill.





And the finished product:




Easy as that. Any comments/suggestions welcome. See my sig for other DIYs.

Looks great! Good job!

Thank you sir

very nice!!!! but i wanted to do it before but did not find any way to remove the sub as ican see it was attached to a bolt on the box , where is that bolt, did not see it.

never mind man, just got it.

but one question how much power the stock amp can handle

The bolt goes through the end of that tube that has to be cut and screws into the back of the stock sub.

How much power can the stock amp handle? Do you mean the stock sub or how much power does the stock amp put out?

The stock amp puts out something like 40w RMS, so I would assume the stock sub cannot handle much more than that. You def want to power the replacement sub with an aftermarket amp.

This DIY is just to keep the clean look of the stock enclosure, I wouldn't recommend replacing the stock sub without replacing the stock amp too.

I'm interested in doing this, but how does it sound since there's really not all that much airspace?

Sounds amazing with my CompVR. The airspace is something like .5 or .6 I remember someone saying, so just get a sub that works with that. Most 8" subs are within that range. I've had a lot of systems in different cars, and I would say the single Kicker 8" in a Tiburon is comparable to a 12" or even two 10"s in many other cars. It easily bumps as loud as the two Kicker Comp 10s I had in my neon.

It's getting 300 RMS from a HiFonics 5-channel amp.

nice man, ive been wanting to do this, the only thing is that my stock sub looks a little different? Do you have to cut the carpeting? Thats the thing thats throwing me off haha. Is there a seam on it or somthing that i am overlooking?

kudos to this thread, well put, and the best part was the pictures where self explanatory. also clean trunk i like it. good job.

doing this within the next few months, i appreciate this. thanks!

Don't have to cut carpet, the carpet on the front of the box comes off entirely, I think it's just glued in a couple spots. The grill might be whats throwing you off.

Thanks!

Happy to help, your welcome.

so im sure my car came with the stock sub in the back but the carpet and enclosure nd everything is gine so i guess someone took it out before they sold the car..

Nice job, great pics too. You make it look simple. I plan to do this soon and was hoping there was a good DIY out her. Thanks!