Factory-Look Audio Upgrades

Tools Required

• Metric allen wrenches
• Tie wraps
• Bentley or Haynes service manual (optional)
• Heat-shrink tubing and misc. wiring accessories
• Other basic hand tools

---

Facilities Needed

• Work bench
• Level, dry surface

---

Parts Required

• BMW factory radio C33/C43/CD43, used $100 - $350
• I-bus data cable, p/n 65 12 8 369 830, $38.00 (optional)
• Factory replacement speakers/amp/subwoofer (optional), $60 - up

---

Getting Started

This write-up is for those who wish to upgrade their 92-95 audio system and retain a clean factory look, although some points apply to all 3 series cars and other BMW's. And there is good reason to upgrade.

For starters, most pre-'96 radio head units are beginning to have display problems (dim display or burned pixels). And by swaping in better speakers or an amp, you can improve sound quality. But most interestingly, by upgrading to a '96-on head unit you'll be able to use mp3 CD changers, iPod interfaces, or even the (discontinued) Phatbox digital media player.

I have organized this section into four different levels of upgrades with corresponding difficulty:

• Level 1 - head unit
• Level 2 - speakers
• Level 3 - data cable (for use with mp3 CD changer/Phatbox)
• Level 4 - amplifier (and/or subwoofer)

All removal and replacement procedures are in the Bentley or Haynes service manual, therefore I will only add additional procedures as necessary. REMINDER: when working with radio head units, be sure to have the BMW security code!

---

Procedure

Level 1 - Head Unit

If you're mostly happy with your factory system, replacing just the head unit is an easy upgrade. A good source for used head units is eBay.

'96-on head units are direct plug-in replacements for 92-95 cars and bring new features such as speed-sensitive volume, three banks of six FM presets, and in-dash CD. There are three models of interest:

1) C33: stock 96-on head unit. (about $100 used)
2) C43: deletes weather band, adds PTY to display program sound type, RDS for radio station ID, and increases voltage output for slightly louder sound. (about $125 used)
3) CD43: adds in-dash CD player. Supports random playback. No mp3 capability. (about $350 used)

None of these units operate 92-95 CD changers (rendering your existing data cable useless) but now will accept an auxiliary input using the CD changer connection on the back of the unit.

This is useful if you wish to play mp3 tunes from an iPod or other portable device. Keep in mind doing so will still require wiring power to your portable device and controlling your music from the device, so you'll need to keep it at arm's length.

There are several interesting iPod interface options. By far the most popular is the iPod integration kit sold by Dice Electronics. It allows iPod control from your head unit and even text display (only with C43 or CD43). Other auxiliary input adaptors can be found at AutoToys or Soundgate.

---

Level 2 - Speakers

Building on the previous step, swapping in better speakers is an easy, inexpensive upgrade. However, this will bring only slight improvements in your sound quality unless paired with a new amplifier.

The easiest pair to replace are the front kick-panel (5 1/4") and rear deck speakers (4"). You use the existing connectors, so no wiring is required. The in-door tweeters on the factory 10-speaker systems are reasonably good and aren't worth the trouble. The rear speakers don't age well, as is evidenced below by this comparison between old (left) and new (right):

Some have recommended cutting out the foam backing behind the front kick panel speakers to improve bass response. I have found this may also cause resonance and vibration to occur, so be advised.

The rear speakers can be changed by just removing the grille covers, leaving the speaker enclosures in place to save time.

I recommend Crutchfield for plug-in speaker upgrades.

Better Bass From Your Rear Speakers Even at moderate volume levels, the rear speaker enclosures don't produce bass very well - even with new speakers. 4x6 speakers can be top mounted in place of the enclosures, with a little extra work, for much better bass response and a noticeable sound improvement. I used Pioneer TS-A4670R, 3-way speakers (image below left).

There is absolutely no room to work with metal cutting tools on the rear deck, so you'll have to use the existing speaker cut-out and screw holes. Cut-off the factory electrical connector and splice in the provided speaker wire connectors. Use heat-shrink tubing. See image above center. Next, cut out a template from 1/4" plywood (which serves to elevate the speaker) and mount the provided factory speaker template with speaker to the plywood. Then secure the plywood using bolts or large screws thru the existing holes in the rear deck sheet metal. See image above right.

 

---

Level 3 - Data Cable

Replacing the old CD changer data cable (runs from head unit to trunk) with the '96-on cable (p/n 65 12 8 369 830) will allow you to add a 6 disc mp3 changer or the impressive Phatbox (now discontinued), and control them from the factory head unit.

NOTE: This change requires a '96-on head unit and the Blitzsafe BMW/ALP DMX V.1 adaptor, which connects in the trunk, before the new changer.

92-95 data cable (left) with power plug (right)	96-on data cable (left) with power plug (right)

This upgrade is a bit more involved however.

The power plug (shown above) will also need to be changed by splicing in. This new plug (above, far right) may be purchased in pieces from a dealer or snipped complete from a salvage yard. The new plug has three wires: 1) red - power, 2) brown - ground, 3) yellow - diagnostics. Splice: new red > old red, new brown > old black. Then, the yellow wire must be routed to terminal 7 in the radio wiring harness.

To obtain a terminal for your harness, use p/n 61 13 1 376 206 or purchase a used radio wiring harness from a salvage yard. With a used harness, use a hack saw to cut it open to extract a terminal. Push the terminal into your harness with a small screwdriver, leaving enough wire length to splice into. These terminals have tiny one-way barbs and cannot be removed once pressed into position. See image below:

Then I ran this wire together with the new data cable as outlined below:

Remove radio (5 minutes) Release old data cable from radio wiring harness by removing blue retaining clip. See image right. Install new I-bus cable into harness (5 min). Remove OBC and parcel shelf, then remove shift knob and shift cover (30 min). Remove center ashtray/cup holder, then rear ashtray and surrounding trim (20 min). Remove rear bench seat, left side bolster, and left rear speaker. See image right, below (30 min). Gather new I-bus cable and diagnostics wire and check length (5 min). Proceed to run both behind the OBC/parcel shelf, around the left side of the shifter, and underneath the center console/cup holder. Use tie wraps (15 min). Push wires thru center of rear console/arm rest, then under carpet to left side passenger seat footwell (45 min). Now route wiring in with existing trunk harness and thru rubber grommet to trunk (15 min). See image right. Limitations: BMW radios and the mp3 changer The compatible mp3 changer is the Alpine CHA-S634 and requires the Blitzsafe adaptor. Packages are available from Crutchfield factory systems. Since BMW head units do not display text or allow direct folder access, mp3 disc navigation will be a concern. Therefore, you may want to limit your mp3 discs to a "flat file" format of about 40-50 songs each, with each disc representing a playlist or genre. Use CD-RW. I like to think of this installation as a regular CD changer with "bonus" capacity. For a tailor-made, large capacity mp3 solution, consider the Phatbox (now discontinued), or an iPod interface.

Running the data cable down the left side and under the driver's side door sill is an option too, but I've found those plastic parts break easily, making it difficult to put back in place securely.

---

Level 4 - Amp/Subwoofer

Replacing the factory amplifier will require even more involved wiring. Doing so however will afford you the most flexibility in improving the sound quality. To achieve the best results you will need to tune your amp's crossover/gain settings to match your speakers.

Since there is no plug-n-play aftermarket amp, you will need to clip off the factory wiring harnesses (2) and use wiring diagrams to splice in. This will also allow a subwoofer to be installed and mounted in the trunk. Mounting these components will need some consideration too.

Be careful of engine noise creeping into your new amp installation and, if mounting a sub, test for undue resonance and vibration.

If you don't want to mess with wiring a new amp but would like to add a subwoofer, there is a plug-n-play subwoofer option available from Bavarian Autosport

  Please leave feedback in my guestbook!

Frankie
Austin, TX