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Head Unit Replacement

Discussion in 'Audio, Video & Electronics' started by nicholas91, Jun 1, 2008.

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    I have 1987 325 and my third BMW radio has died. I wanted to replace it with an alpine unit but i was told that the installation costs would be large because they would need to bypass the factory amp. Is this true and do you have reccomendations for a replacement.
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    I installed an Alpine unit into my 325e successfully. Given, my previous radio was aftermarket and not stock. I don't know what other 'mods' the previous owner did and I don't know which/where the amp might be located, but there is a box-like unit under the passenger seat; would this be the amp? If so, what would the factory unit look like?

    My Alpine unit works flawlessly, specifically the iDA-X300. I didn't have to do anything other than take the old radio out, hook up the wires to the new one, (punch out my rear-window defroster switch so I could route the iPod cable through there), and install the radio. Simple.
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    Well, you have options - the original radio in E30's used a booster amp, and didn't have the fader built into the head unit, it's a scroll wheel in the dash. Furthermore, the head unit uses a common ground for the speaker leads (ie, there are only pos. leads from the head unit to the booster amp). Exiting the booster amp, there are pos/neg leads for the speakers.

    BTW, this is based on my experience w/ my '87 325is, it is entirely possible non-'is' E30's did something different, but I think most E30's were setup this way. Later E30's had a wiring setup that I think you can use a Crutchfield adapter for, but the earlier ones it's just several plugs and wires.

    If you don't want to be a hyper-picky audiophile, you can wire up any head unit w/ the factory wiring and you'll be feeding your radio's signal through the booster amp. There will probably be some improvement in sound quality, it'll work, and you can manage the install. If you want an optimized setup, that would mean running your own wiring, bypassing the factory stuff, and pulling the interior and a lot of trim pieces, if not the entire carpeting (which I think you have to get into pulling the dash to do), in order to run your own wiring (assuming you'd want it out of sight of course - I suppose there's always the duct-tape-the-wiring-to-the-headliner approach....).

    The downside of the simplest approach is (at least for me) is your max volume level is going to be limited by the booster amp. But, I can live with it, I don't need or want to max-crank tunes all that often anyway.

    I stuck an older alpine head unit in my E30 a couple of years ago, and a JVC radio w/ built-in hd tuner in my E34 last year. For awhile I thought it would be nifty to have a head unit that would play a dual-sided dvd you might burn w/ your own .wav's or mp3's, or several gb usb flash drive, but since there's a 160gb ipod out there, I don't see anything eclipsing that amount of storage anytime soon.
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    This is a later model E30 wiring schema - earlier ones were different -


    This is for reference - earlier E30 radios will be kinda similar to the pics at the bottom - but it's generally useful for comparison purposes (this link is for a early E34 5'er radio).


    Oh ya - if your car has the booster amp, it's probably above the left rear wheel well, behind the trunk trim panel. Not sure if it may have been on the other side in some models - might be possible.

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