BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > DIY Guides/ Discussions
 
Evolve Automotive
Post Reply
 
Thread Tools Search this Thread
      01-10-2012, 03:48 AM   #1
IrishCoffee
First Lieutenant
IrishCoffee's Avatar
7
Rep
370
Posts

 
Drives: '11 E92 M3, '14 328i, '14 1LE
Join Date: May 2011
Location: San Diego

iTrader: (0)

DIY: Fiberglass Subwoofer Enclosure

Hello Everyone

I just built a fiberglass enclosure for my E92 M3 and thought I'd do a DIY for those interested.

I have the premium audio and think it sounds great. I just wanted a little more low-end to round it out. I decided to add a JL Audio 10W6-V2 in a small sealed enclosure in the left corner of the trunk. Trunk space is important to me so it needed to be out of the way and not cause any problems with accessing any areas of the car. Also, I wanted to make sure it was easily removable for days at the track or if I really needed the extra room on a trip.

I worked in a car audio store as a teen and have done a couple of these before. They aren't necessary difficult to build, but there is a lot of work involved, and a lot of chemicals. You need to have an area available to you that is fairly well ventilated and allows for a mess to be around for a few hours at a time. Don't do this in your house or on your balcony... your wife/girlfriend will kill you due to the mess and the fumes.

Overall this project took me about 20-25 hours of labor. There is a lot of time waiting between coats of fiberglass and you need to make sure you do things properly otherwise it will be a mess. You need patience for this.

A few words about fiberglass work if you've never done it before. Avoid contact with fiberglass resin and cloth/mat. It has a tendency to get all over you hands and arms and is a pain to clean off. I wear a sweatshirt and latex gloves when working with the stuff. Also, I recommend a dust mask at a minimum for fumes and while sanding. Acetone will clean up any resin that gets on your hands, but rubbing acetone all over your hands several times a day causes some pretty serious irritation to your skin.

Please use safety glasses when cutting and sanding. I've had shards of wood and fiberglass hit my glasses before. I can't imagine losing an eye over something so stupid. Just do it.

Hardware Store Supplies ~ $125 total
  • 1 small piece of MDF for the baffle. No need to get an entire sheet. Don't use crappy particle board. Get the MDF. I think the small sheets at home depot are 2'x4'
  • 1 small piece of 3/8" or 1/2" MDF for the baffle cover.
  • 1 gallon fiberglass resin
  • 1 small can of Bondo
  • 1 pack of fiberglass cloth
  • 2 packs of fiberglass mat
  • 1 medium container of Acetone
  • 5-10 disposable paintbrushes
  • 1 bag of ~50 disposable gloves
  • 1 pack of disposable masks
  • 1 pack of sandpaper 80 grit
  • 1 large roll 3.5 mil plastic
  • 1 large roll of masking tape
  • 1 putty knife
  • 4 medium disposable mixing cups/containers
  • 4 paint stirrers
  • 1 roll of tin foil
  • 1 bottle of wood Glue
  • 1 pack of basic 1.5 wood screws
Upholstery Store ~ $35 total
  • 2 yards of backless trunk liner to closely match the BMW fabric. I used Keyston Brothers trunkliner TL04
  • 1 can of spray adhesive

Tools needed:
  • Jigsaw
  • Power Sander of some sort
  • Safety Glasses
  • Razor
  • Scissors
  • Tape Measure

OK, let's do this. First I pulled the left trunk trim panel out. There are a couple of black clips that need to be popped out and one torx screw near the rear seats. After that the whole thing can be worked out with a little force.


First I make some templates out of scrap cardboard to fit the trunk liner bottom and side profile. Then I trace them on the MDF and cut them out with the jig saw. Here they are during a test fit.


After the baffle is done I use the 3.5 mil plastic and cover the entire piece using masking tape to hold it down. This is difficult and may require using several layers and a lot of tape. This will be frustrating trust me.


Once completely covered I add aluminum foil and more tape as a easy release layer. It also adds extra protection to the trunk liner. If you get resin on the trunk liner it's pretty much done for. I also slipped the bottom piece in for a test fit.


Now, it's time to get messy. First I cut the fiberglass cloth into strips about 4 inches wide by 10 inches long. Then I use spray adhesive to adhere them to the inside of the tin foil. This allows them to stay in place better while adding the resin. Then I mix about 12 ounces of resin in one of the disposable cups and stir it up with the catalyst. Use one of the disposable paint brushes to lay it onto the fiberglass cloth evenly.


Repeat this process several times allowing it to dry. I use the fiberglass cloth first because it's thin and easy to manipulate. After the first layer I use the mat because it's thicker and builds the enclosure up quicker. Once you've applied several layers and it has dried you can take it out of the trunk liner. Remove the plastic from the trunk liner and hope that no resin leaked onto it. If it did then I guess you'll be going to Tischer to order another because there is no way to clean it off. Here it is popped out of the mold from the front and rear.



Then I use the jigsaw to cut the excess off as square as I possibly can. This takes a few passes and some eyeballing. I then sand the excess resin off the bottom piece in order to prepare to attach the baffle.


Using wood screws and a countersinking drill bit I attach the baffle to the MDF base. I then use more resin and fiberglass cloth to seal the gaps around the edges.


Test fit... looking pretty reasonable


Next I add an extra baffle ring to add some additional mounting depth for the speaker. I also attach the second baffle (made of the 3/8" MDF) to original the 3/4" piece. This top baffle protrudes about a half an inch around the edges of the enclosure and really just fills the gaps around the edges. It is purely aesthetic.


I then add Bondo to areas that need a little filling in and areas that I want to smooth out. Bondo is great stuff and is very moldable. You'll be tempted to use your hands to mold it. Use gloves. This stuff is really hard to get off your hands.


I then use my palm sander to sand all the rough areas smooth. I then hand sand it until I am happy with the result. It doesn't have to be perfect; the fabric will cover up small imperfections.


Test fit


Next I use the spray adhesive and a razor blade to apply the finishing fabric. I also add a ring terminal for easily disconnecting and reconnecting the speaker. A bag of poly fiber fill is added to the enclosure for acoustic purposes.


I then screw in the sub and the grill


And it fits! The fabric is about a 90% match which is excellent.




I added a JL Audio XD 600/1 to power the sub. I am in the process of finalizing the install for that and the Audio Control LC2i and will post pics when finished. I hooked it all up and it sounds great. It looks stock and is easily removable so I am happy.

The weight and the snug fit alone keep it in place really well. However, I am looking into adding a small bracket of some sort to make sure it stays in place in case of a hard left turn or something worse. I'll update the thread when I finish that too.

Many thanks to everyone who has posted other audio installs for ideas and info. Particularly, thanks to Technic for his hundreds of useful posts regarding wires, pin configurations, etc. These are really what forums are great for.

Also, I did something very similar in my 2008 Infiniti G37 there are more pics and instructions for that project here: http://www.myg37.com/forums/audio-vi...r-install.html
Appreciate 0
      01-10-2012, 07:06 AM   #2
NYCM3ryder
Razzor
United_States
6
Rep
514
Posts

 
Drives: JB E90 M3
Join Date: Aug 2010
Location: New York City

iTrader: (0)

wow, looks great snug fit and clean. This is something i would like to add to my car.. good job.
__________________

2011 E90, 6 speed, technology package, black 220 rims , EDC, moon roof, matt black grills, matte side grills, 15% carbon tints, carbon fiber M pedals, ACS roof wing, IND painted reflectors, mfest black gloss m3badges, Mfest side window stickers, Tuner MS 15mm spacers, Carbon fiber M foot pedals, MS air filter, RPI air scoops, euro switch mod
Appreciate 0
      01-10-2012, 09:34 AM   #3
THE TECH
BimmerPost Supporting Vendor
THE TECH's Avatar
United_States
157
Rep
13,121
Posts


 
Drives: BPMsport 2012 E92 M3
Join Date: Jun 2011
Location: Kansas

iTrader: (45)

Garage List
Send a message via AIM to THE TECH Send a message via Skype™ to THE TECH
Very nicely done!
__________________
Appreciate 0
      01-10-2012, 10:50 AM   #4
Ken37.73
Private 1st Class
Ken37.73's Avatar
7
Rep
473
Posts

 
Drives: E92 M3 Jet Black
Join Date: Jan 2008
Location: Ireland

iTrader: (0)

Wasn't sure what to expect but that is a tasty job - fair play.
__________________
Appreciate 0
      01-10-2012, 12:33 PM   #5
bigjae1976
That's what she said...
bigjae1976's Avatar
84
Rep
5,651
Posts

 
Drives: 11 E90 M3 Individual
Join Date: Mar 2006
Location: Milwaukee, WI

iTrader: (12)

Garage List
2004 BMW M3  [4.50]
2011 BMW E90 M3  [5.00]
2013 BMW 328i  [5.00]
Good job. Only comment is I would have added some bracing - front to rear.
__________________


Sponsored by Momentum BMW #593...We Bleed BMW BLUE!
Appreciate 0
      01-10-2012, 03:13 PM   #6
chili cheese
Captain
chili cheese's Avatar
17
Rep
960
Posts

 
Drives: '13 E92 M3, Santorini Blue
Join Date: Jul 2007
Location: Southern CA

iTrader: (6)

Hey man, nice job and nice thread. I've seen and heard this and it's great! It looks OEM to be sure. He knows what he's doing here folks.
Appreciate 0
      01-10-2012, 04:00 PM   #7
Orange fever
Lieutenant Colonel
Orange fever's Avatar
Thailand
33
Rep
1,660
Posts

 
Drives: E46M,E90M,X5M,135I
Join Date: Dec 2007
Location: in the hood!!!

iTrader: (5)

I love it
__________________

X5M E70 Black Sapphire Metallic,VF Engineering Hex Flash Software,Vorsteiner-FrontSpoiler/RearDiffuser
2012 135i/E82 N55 LeMans Blue ///M-SPORT
Appreciate 0
      01-10-2012, 04:10 PM   #8
tlp
Colonel
tlp's Avatar
United_States
70
Rep
2,066
Posts

 
Drives: '11 e92 M3 SG/FR
Join Date: Jul 2005
Location: Huntington Beach, CA

iTrader: (6)

Garage List
2011 BMW e92 M3  [4.55]
Nice. Next time make a few sets in parallel, I'm sure they would sell.
__________________
My Coding Journal
Current - '11 e92 M3 SG/FR ZCP|ZCV|ZP2|2MK|494|415|6NR|752
Appreciate 0
      01-10-2012, 08:20 PM   #9
Brucewonder
Lieutenant Colonel
Brucewonder's Avatar
17
Rep
1,544
Posts

 
Drives: 2011 E92 M3 yea boi
Join Date: Nov 2007
Location: Socal

iTrader: (4)

me likie
__________________
2011.5 E92 ///M3 SSII/FR
Appreciate 0
      01-10-2012, 08:26 PM   #10
GIdriver
Major
GIdriver's Avatar
United_States
17
Rep
1,353
Posts

 
Drives: 2014 E63 AMG-S
Join Date: Dec 2010
Location: Somewhere in Time

iTrader: (0)

Good job!
Appreciate 0
      01-10-2012, 09:17 PM   #11
kmarei
Major General
kmarei's Avatar
Egypt
130
Rep
6,481
Posts

 
Drives: 1988 E30 M3 Evo II
Join Date: Jul 2008
Location: Reston, VA

iTrader: (33)

Garage List
damn impressive
the mounting hole for the 10W6-V2 is 9"
you think you could fit a 12.5" hole to use the 13TW5?
that sub is good as it only needs 2.5" mounting depth and only needs a 0.8 cubic foot enclosure

i wonder how it would sound if i was only using the baffle
sealed against the trim with weather stripping
hmmmm
__________________
This user has been banned from the 4 series forum because he doesn't sing its merits like the admins want us all to

Appreciate 0
      01-10-2012, 11:11 PM   #12
IrishCoffee
First Lieutenant
IrishCoffee's Avatar
7
Rep
370
Posts

 
Drives: '11 E92 M3, '14 328i, '14 1LE
Join Date: May 2011
Location: San Diego

iTrader: (0)

Quote:
Originally Posted by kmarei View Post
damn impressive
the mounting hole for the 10W6-V2 is 9"
you think you could fit a 12.5" hole to use the 13TW5?
that sub is good as it only needs 2.5" mounting depth and only needs a 0.8 cubic foot enclosure

i wonder how it would sound if i was only using the baffle
sealed against the trim with weather stripping
hmmmm
The extra mounting ring in the photos was right around 12" so it seems like it could fit!
Appreciate 0
      01-10-2012, 11:13 PM   #13
IrishCoffee
First Lieutenant
IrishCoffee's Avatar
7
Rep
370
Posts

 
Drives: '11 E92 M3, '14 328i, '14 1LE
Join Date: May 2011
Location: San Diego

iTrader: (0)

Thanks for all the compliments guys! I hope someone finds the post useful at some point!

Appreciate 0
      01-11-2012, 12:06 PM   #14
coogs08
Second Lieutenant
3
Rep
262
Posts

 
Drives: 2009 M3
Join Date: Aug 2011
Location: Pearland, TX

iTrader: (2)

Great job and thanks for the write up!
Appreciate 0
      02-08-2012, 03:06 PM   #15
Templar
Lieutenant Colonel
Templar's Avatar
United_States
40
Rep
1,824
Posts

 
Drives: 2011 E92 M3
Join Date: Feb 2009
Location: One of the coasts...

iTrader: (1)

Garage List
2011 BMW M3  [5.00]
Where did you put the XD 600/1 for power for the sub? Just interested in how you finished the project (if finished yet that is). Otherwise this is definitely something I'd like to do sometime! Looks great!
__________________
'11 BMW E92 ///M3 - ZCP and DCT
'13 Toyota Tundra - 4x4 Platinum CrewMax, 5.7l iForce V8
Appreciate 0
      02-08-2012, 03:08 PM   #16
THE TECH
BimmerPost Supporting Vendor
THE TECH's Avatar
United_States
157
Rep
13,121
Posts


 
Drives: BPMsport 2012 E92 M3
Join Date: Jun 2011
Location: Kansas

iTrader: (45)

Garage List
Send a message via AIM to THE TECH Send a message via Skype™ to THE TECH
Quote:
Originally Posted by Templar View Post
Where did you put the XD 600/1 for power for the sub? Just interested in how you finished the project (if finished yet that is). Otherwise this is definitely something I'd like to do sometime! Looks great!
It fits great under the trunk floor compartment.
__________________
Appreciate 0
      02-08-2012, 03:55 PM   #17
IrishCoffee
First Lieutenant
IrishCoffee's Avatar
7
Rep
370
Posts

 
Drives: '11 E92 M3, '14 328i, '14 1LE
Join Date: May 2011
Location: San Diego

iTrader: (0)

Quote:
Originally Posted by THE TECH View Post
It fits great under the trunk floor compartment.
Exactly... I put the XD600/1 and the LC2i in the shallow plastic area. I specifically chose this amp because it fits under there and I didn't want to waste space anywhere else. Works great with a tiny footprint.
Appreciate 0
      02-08-2012, 03:57 PM   #18
THE TECH
BimmerPost Supporting Vendor
THE TECH's Avatar
United_States
157
Rep
13,121
Posts


 
Drives: BPMsport 2012 E92 M3
Join Date: Jun 2011
Location: Kansas

iTrader: (45)

Garage List
Send a message via AIM to THE TECH Send a message via Skype™ to THE TECH
Quote:
Originally Posted by IrishCoffee View Post
Exactly... I put the XD600/1 and the LC2i in the shallow plastic area. I specifically chose this amp because it fits under there and I didn't want to waste space anywhere else. Works great with a tiny footprint.
+1
__________________
Appreciate 0
      04-02-2012, 07:43 AM   #19
RuthlessE90
First Lieutenant
No_Country
3
Rep
324
Posts

 
Drives: FAST
Join Date: Mar 2011
Location: NYC

iTrader: (5)

This is nice I want one for my e90
__________________
Appreciate 0
      04-02-2012, 09:11 AM   #20
Scrappy
Private First Class
5
Rep
166
Posts

 
Drives: E92 M3
Join Date: Oct 2010
Location: Jacksonville, FL

iTrader: (0)

AWESOME JOB!!! You should make and sell these because I'd surely buy one!
Appreciate 0
      04-02-2012, 12:53 PM   #21
IrishCoffee
First Lieutenant
IrishCoffee's Avatar
7
Rep
370
Posts

 
Drives: '11 E92 M3, '14 328i, '14 1LE
Join Date: May 2011
Location: San Diego

iTrader: (0)

If I had a good space to do it I probably would make several at once. I don't think my neighbors would be too happy if I was constantly stinking our common garage up with fiberglass fumes though! They were already looking at me like I was crazy while making this one.
Appreciate 0
      06-02-2012, 10:09 PM   #22
RuthlessE90
First Lieutenant
No_Country
3
Rep
324
Posts

 
Drives: FAST
Join Date: Mar 2011
Location: NYC

iTrader: (5)

So are you gonna make some of these or what. I want one
__________________
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 11:04 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST