(E92) Help! Stock head unit with aftermarket amplifier and sub-woofers. (DIY)

I'm looking to put in an aftermarket amplifier along with two sub-woofers in the trunk of my E92. I believe I have the hifi system as I have two tweeters in the front of the car. I want to keep the stock head unit. I'm a little confused as to how I am going to get the remote and RCA cables from the head unit to the amplifier. I really want to keep everything as bone stock as possible.

I think you can run it through the drivers side foot sills that touch the carpet of the car. I'm not sure how to remove them however. I'm still not sure how I'd get the wiring from the head unit to the door sills either.

Any help appreciated, pictures to go along with and comment would be amazing!

The door sill trim is held down by a number of clips. The clips have squarish heads that run in a channel down the center of the underside of the sill trim. Each clip snaps into a hole in the body sheet metal. You remove the sill by carefully prying it up to free the clips, using non-marring pry tools (i.e., nylon trim removal tools, a stiff putty knife or screwdriver wrapped in electrical tape, or similar). It sometimes helps to slide the trim fore-and-aft on the channel as you work each clip. If you have never done this before, you are almost certain to ruin a few of the clips in the process (and the trim if you are not careful and patient). The good news is the clips are cheap (typically under a buck apiece) and readily available from any BMW dealer's parts department.

You might want to consider buying a Bentley repair manual for the car. It's the best $120 you will ever spend on the car and will pay for itself in a DIY project or two. It will probably help you find the easiest way to route cables to one of the door sills--"easiest" in the sense of removing the minimum number of components to get the access you need.

Incidentally, the passenger side is often the easier way to go. Mechanically speaking, there is less going on in the passenger footwell and you generally have more room to work, with less crowding from existing components.

One final word of warning: Be very, very sure you know what you are touching when you start monkeying with the factory wiring harness in a BMW (see "Bentley manual," above). Apart from the fact that these cars are sensitive to electrical modifications, not every "wire" you see is in fact a wire. BMW uses a fiber-optic bus to interconnect a number of systems (I am not kidding) and if you damage that, your wallet may not recover for a long, long time.

You have more problems than just running wiring.

No BMW head unit has pre-amp outs for RCA connectors. If you have the hifi unit, the amp in the head is integrated and has the cross-overs in it. You have to either tie into the speaker wires for the subs (under the front seats - might have to remove them), or tie into all the speaker wires and re-construct the full audio range (if your amp needs that).

As far as running wiring, the door sills pop out and you can then run things easily under the edge of the carpet. The rear seat bottom should just pop out (pull up hard). Not sure about the dash and center console.

Go over to the audio forum and search around.

So how do I go about tieing into the stock subwoofer wiring? They are the blue cables with white stripes correct? I want to try and avoid as much as possible, any modifications to the stock equipment in the car.

Could I grab the subwoofer signal from the cables going into the stock amplifier in the trunk? And then just somehow get the remote cable to go off of one of the fuses behind the glove box and run that through the sills to the trunk?

http://www.e90post.com/forums/forumdisplay.php?f=27

and look at this

http://www.e90post.com/forums/showthread.php?t=641323

and these

BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/showthread.php?t=343673
http://www.e90post.com/forums/showthread.php?t=138949
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/attach...1&d=1209780865
http://www.google.com/url?sa=t&rct=j...QNFyu70IsyKRlg
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...4&d=1278871872

and start asking questions at the first link listed.

You should identify the model year of the car and which of the three system types you have first.
There are also detailed procedures at the E90 post audio board and DIY board as to how and what to install.
And detailed procedures for taking the door panel off , changing speakers and adding audio equipment.


THERE ARE SCREWS UNDER THE WOOD TRIM HOLDING THE DOOR PANEL ON AS WELL .
So read the procedures on how to remove the door panels before you even start.

MusicarNW has kits with everything you need to give you and audiophile system without cutting or soldering .
They are not cheap kits they come with high end speakers amps/processors they have known solutions
and can tailor the system and components to your taste.

What does a harness do exactly? My basic understanding is that it goes between the oem amp and oem wires, correct? But what is its purpose?

Sorry I am very very new to this.

A harness allows plug and play hookup . That means no wires need be cut and no soldering is necessary. This makes things easy to plug in and add , also the better harnesses will have everything labeled . So with a harness you don't mess up your car wiring and you can return it to stock easily. There are harnesses for adding aftermarket Head Units , Amplifiers and/or connecting speakers and other devices.
There are three different stereo systems offered by BMW world wide as described in the documents supplied. There is a different Harness for each . A guy named Technic makes and sells Harnesses that fit specifically on E9x series, he sometimes posts here and a lot on the e90post stereo board.

If you just want to add subwoofers or anything else the guys on the stereo board can help you.
That should be fairly simple and the wires you want to tap are already in the trunk for a bass amp and a subwoofer
Also MuiscarNW makes a subwoofer kit for the trunk.
If you want something really nice I suggest you rework/change most of the speakers and change the amp.
There are many examples in the links supplied.

Originally Posted by RyanAustinOlson

I'm looking to put in an aftermarket amplifier along with two sub-woofers in the trunk of my E92. I believe I have the hifi system as I have two tweeters in the front of the car. I want to keep the stock head unit. I'm a little confused as to how I am going to get the remote and RCA cables from the head unit to the amplifier. I really want to keep everything as bone stock as possible.

I think you can run it through the drivers side foot sills that touch the carpet of the car. I'm not sure how to remove them however. I'm still not sure how I'd get the wiring from the head unit to the door sills either.

Any help appreciated, pictures to go along with and comment would be amazing!

All you need is at the trunk. There is no need to run any wires throughout the car.

Please PM for details on a custom, no OEM wires cut, PnP connection for an aftermarket trunk sub/amp install while keeping the OEM amp in place:

Originally Posted by Technic

All you need is at the trunk. There is no need to run any wires throughout the car.

Please PM for details on a custom, no OEM wires cut, PnP connection for an aftermarket trunk sub/amp install while keeping the OEM amp in place:

Awesome! Thank you for your response.

I would love to purchase a HIFI harness from you. I sent you an PM as you told me to do.

I would like one too!