Looking into an OEM radio

I have my original head unit available (I converted to the blaupunkt CD43 to get iphone integration).

OEM head units use a different connector from aftermarket head units:

• OEM: Proprietary 17-pin connector with round pins
• Aftermarket: Two 8-pin ISO connectors (usually)

But don't worry: there's probably a BMW-to-ISO adapter cable installed in your car. Just remove the adapter cable to install an OEM head unit.

During the 10 years of production, BMW used a fair amount of different head units in the E31. Reinhard posted a great overview but the thread is only accessible to supporting members (and it's in German). Most OEM head units are not worth looking at other than nostalgia. Sound quality is poor and many are plain ugly. In my opinion there are only 2 OEM head units worth of installing if you care a bit about looks and sound quality (and plug-and-play compatibility):

BMW Business CD

Type: Radio CD player
Manufacturer: Blaupunkt
Model: CD43
Original BMW order option: 658 (note this code was used for various head units in the E31)

(picture taken from reinhard's post)

Introduced close to the end of production the BMW Business CD is nowadays one of the most sought-after OEM head units for the E31. Its sleek design, modern CD player (most head units had cassette players), and excellent sound quality make it a very desirable choice for OEM-fetishists. Through aftermarket interfaces it's even possible to hook up mp3 players that you can operate from the head unit (although it's best to read up about it because there can be quirks with some models).

The BMW Business CD is almost always referred to by its Blaupunkt models number: CD43. Please note that the head unit was also manufactured for the Rover brand. You will find a lot of CD43 for sale with a BMW ///M logo right from the volume knob. That's actually a decal covering the Rover logo. Genuine BMW head units have "BMW BUSINESS CD" printed there instead. Other than the decal the head units are identical.

BMW Professional RDS

Type: Radio cassette player
Manufacturer: Becker
Model: BE2450
Original BMW order option: 670

(picture taken from reinhard's post)

The top model head unit starting from 1995. Excellent sound quality, trademark dual tuners, gorgeous large display, but the cassette player makes it look a bit dated. It was meant to be combined with a trunk-mounted 6-disc CD changer. If you intend to replace the CD changer with an MP3 player you are better off with the CD43: Despite the nice and large display, the BMW Professional RDS cannot display text submitted over its CD changer interface which really limits the usability with MP3 players.

You can't ask for a more precise answer than that!

user2883: I'm not really familiar with order option 687 but since there's a separate order code for CD changer preparation (694), I assume the CD changer wiring is not included with 687.

Anyway, the CD43 has a built-in CD player. Unless you don't like swapping discs frequently you don't need the CD changer. If you want more music I would recommend to look into hooking up an MP3 player to the CD43. If you are really determined to get the CD changer, make sure you get a cable and CD changer that is compatible with the CD43. BMW used various CD changers with different cables over the years which are not exchangeable. Note that in order to mount the CD changer in the trunk you may need additional mounting parts, a different floor mat and side trim.

I´d agree here in not expecting too much out of S687

The CD player wiring will not be included because there were two varieties up until BMW gave up using the 2-block Professional C RDS system (S662).

I´d expect that the basic set of speakers (footwell, rear parcel shelf & (maybe not complete) doors) has been installed along with the wiring going to the speakers. There won´t be an amplifier in the boot and consequently no wiring loom leading to and fro. The speaker setup will be even more basic than what came optioned as S676. The ones under the rear parcel shelf are just a single chassis and IIRC the same holds true for the door setup.
This does not mean that it will produce much less of a noise than the S676 HiFi system but since this is far from audiophilic anyway one has to adjust the expectations

The CD43 will be plug and play.

Cheers
Reinhard

None of the radios and speakers built in to the 8 series can be considered Hi Fidelity...
The same goes for the E39 and therefore I built in a little subwoofer from Pioneer.
It fits nicely underneath the seat or in the boot and supports the original radio (which has no bass at all) very well.
It is small but has a surprising "punch".
Of course it is no match to a real high end audiophil setup but it's cheap and it makes a standard radio sound a lot better.

Cheers
Steve

Zitat von reinhard;127562

I´d expect that the basic set of speakers (footwell, rear parcel shelf & (maybe not complete) doors) has been installed along with the wiring going to the speakers. There won´t be an amplifier in the boot and consequently no wiring loom leading to and fro. The speaker setup will be even more basic than what came optioned as S676. The ones under the rear parcel shelf are just a single chassis and IIRC the same holds true for the door setup.

That's right. No boot amplifier and only 6 speakers (of which none are the same as the hifi system).

Stereo system

• Footwells: 2 x 25 W woofer
• Doors: 2 x tweeter (unknown wattage)
• Rear parcel shelf: 2 x 25 W woofer

Hifi system (order option 676)

• Footwells: 2 x 40 W woofer with bass reflex enclosure
• Doors: 2 x 15 W mid-range + 2 x tweeter (unknown wattage)
• Rear parcel shelf: 2 x 40 W woofer with bass reflex enclosure + 2 x 15 W mid-range + 2 x tweeter (unknown wattage)
• Boot amplifier: 4 x 25 W (up to September 1993) or 10 x 25 W (from September 1993)

All speakers have 4 ohm impedance. The power ratings of the amplifiers vary from source to source (4x15 to 4x25 W for the early system and 10x20 to 10x25 W for the later system) and should be taken with a grain of salt.

No difference to my understanding.

There will be two codes (atleast with a new unit) which will adjust the frequency to either EU or US bands when at first "boot".
I bought a new one some years ago from Ebay and it has been working well and looks good too.