BMW Z3 Model 68 Subwoofer  Installation Instructions
BMW Z3 Model 68 Installation Instructions
IMPORTANT:  Read these instructions from start to finish twice before you even go near the car!  Professional installation is recommended for those who are unfamiliar with car audio.  These instructions assume you have already installed your new amplifier.
What’s Included:
1. The Model 68 enclosure cabinet
2. 6” x 8” neodymium subwoofer
3. Foil-backed damping sheet
4. Gold-plated wire terminal cup
5. 1/16” grey self-adhesive gasket foam (26”)
6. 1/4” black self-adhesive gasket foam (30”)
7. 1/4” x 4.5” hex bolt
8. 1/4” x 1” hex bolt
9. 1/4” flat washer
10. Rivet nut
11. Rivet nut installation wrench
12. (4) #8 x ¾” phillips pan-head screws
13. (4) #8 x 1/2”phillips screws
14. 14 AWG speaker wire (18”)
15. (4) 1/4” wire terminals
What You Will Need:
1. Power drill
2. 1/16” and 7/16” drill bits
3. Philips screwdriver
4. 7/16” socket driver or wrench
5. Stiff-blade putty knife or similar flat bladed tool
6. Utility knife, diagonal flush cutters, or small hacksaw
7. Center punch or marking pencil
8. Wire strippers/crimpers
1. Carefully remove the subwoofer enclosure cover by first
lifting the rear edge of the cover and then lifting entire
cover straight up. The cover should lift out with minimal
effort, but may require some additional effort to release the
rear snaps. Take your time and be careful when removing
the sub lid! The easiest thing to do is to insert a flat, metal,
handled-tool like a stiff putty knife and carefully pry each
side up from the back.  NOTE: If you have the storage
compartment, you may find it easier to temporarily remove
the storage compartment lid while performing the install.
Remove the old enclosure
2. Remove the 4 mounting screws (2) from the existing speaker
enclosure (1).  If you have the storage compartment, remove
the screws holding the compartment liner and lift out the liner.
3. Remove the old enclosure (1) by pulling upwards. Disconnect
the wiring harness connector (2) and remove the entire enclo-
sure from vehicle.
4. Using a knife, diagonal flush cutters or small saw, carefully
trim away the 4 plastic extrusions (2). If you have the storage
compartment, remove the (4) center extrusions—Do Not re-
move the extrusions the storage compartment lid hinges
mount to.
5. Remove the old foam insulation from the rear panel of the
sub compartment.  Remove the backing from the sound mat-
ting and apply in the upper center portion of the rear plastic
panel. Press matting firmly against panel to ensure complete
adhesion.
Prepare the Subwoofer Compartment
Overview: The Model 68 enclosure is designed with the speaker facing toward to the rear of the vehicle.  The “L” shape in the back/bottom of the enclosure faces the front of the vehicle, and rests over the beam that runs sideways through the enclosure compartment.  The protru-sions on the speaker side of the enclosure are standoffs to ensure proper clearance between the speaker and the plastic panel at the rear of the subwoofer compartment.  The round hole drilled from top to bottom in the back of the enclosure (the part towards the front of the vehicle) accommodates the mounting bolt.  The wire terminal cup mounts in the rectangular hole in the driver’s side of the enclosure.
1. The Cut (2) 12” and (2) 3” lengths of the Black Foam Gasket Tape.  Remove the kraft pa-
per backing and attach one 12” length to each downward facing horizontal section of the enclosure.  Be sure not to cover the hole for the mounting bolt—place that length of gasket between the mounting hole and outside edge of the enclosure.  Attach the two 3” lengths to the front of the standoffs on the speaker-side of the enclosure.
2. Place the enclosure in the subwoofer compartment.  Push the enclosure down and toward
the front of the vehicle—you want to make sure the “L” shaped notch in the enclosure is as close to flush against both sides of the beam as possible.  Make sure the enclosure is cen-tered side-to-side as well.  While holding the enclosure in place, use the center punch or marking pencil to mark the center of the mounting bolt hole on the top
of the beam.  The accuracy of this mark is critical, so take your time
and be certain you’ve got it marked correctly—double, triple, quadruple
check it!!
3. Remove the enclosure and drill a 7/16” hole in the location marked in
step 2.  A good quality Cobalt metal drilling bit will make this step eas-
ier.  The beam is hollow, just drill a hole through the top and stop.
4. Insert the Rivet Nut into the hole drilled in step 3.  Insert the 1/4”
x 1” hex bolt through the Rivet Nut Installation Wrench and
thread the hex bolt into the Rivet Nut.  You want the Rivet Nut
Installation Wrench oriented with the “grip dots” facing the Rivet
Nut.  Use a 7/16’ wrench or socket to tighten the hex bolt until the
Rivet Nut is securely fastened in the hole.  (NOTE:  The picture
at right shows a thumbscrew threaded into the Rivet Nut rather
than the hex bolt included with your kit).  Remove the hex bolt
and installation wrench.  The Rivet Nut should remain secure in the hole.
5. Using the (4) #8 x 1/2” screws, mount the wire terminal cup in the rectangular hole in the
driver’s side of the enclosure.  You may find it helpful to drill pilot holes using a 1/16” drill bit.
6. Using a stripper/crimper tool, strip the ends of the 18” length of speaker wire and attach the
(4) wire terminals.  Attach one set of terminals to the back of the wire terminal cup.
7. Remove the kraft backing from the Grey Gasket Foam and affix it around the front face of
the enclosure immediately adjacent to the speaker hole.  Trim the excess with scissors and be sure you have no gaps in the seam where the ends meet.  This thin gasket tape will make an airtight seal between the speaker and the enclosure.
8. Attach the speaker wire/terminals to the speaker and place the speaker in the enclosure.
Mark and drill 1/16” pilot holes for the (4) #8 x 3/4” pan head screws.  Attach the speaker using the screws.
9. Place the enclosure back in the vehicle and connect the wiring from your amp (installed
previously) to the terminal cup.  Place the 1/4” washer on the 1/4” x 4.5” hex bolt.  Attach the enclosure to the vehicle by inserting the 1/4” by 4.5” hex bolt through the mounting hole in the enclosure and threading it into the Rivet Nut.  Use the 7/16” wrench to tighten the hex bolt until it is snug.
10. Adjust the gain on your amp keeping in mind the 80 watt RMS max of the sub , and enjoy! Mount the Speaker & Attach the Enclosure