Basic Amp and Subwoofer Install in M3 (F8x)

[TCom]

I picked up my 2018 M3 ZCP a few weeks ago and wanted to install a very basic sub setup into the car. One of the things I always find a little frustrating is finding some really basic info for best fuse to use for amp signal and which wires to hook a line out converter to. Here is what I learned from pulling info out of a few different discussions along with some photos I marked up. I hope will help others with this work.

1) Factory wires to get signal from:
Thanks to a post that had an italian picture the colors were the same and are the thick wires in the harness. We were able to splice into them without removing the trunk panel but did unplug all of the harnesses. This harness requires the housing to slide to the passenger side and then pulled out (was difficult by hand and pried out with tool)

Black/Red (Positive)
Black/Tan (Negative)
Blue/Red (Positive)
Blue/Tan (Negative)



2) Fuse to get signal power from:
Next was finding a good switch power fuse to run the amp signal wire to. With a little trial and error and the paper diagram in the fuse box we settled on fuse 159 that corresponds to the radio. We ran a fuse connector off of 159 to the amp.





3) Hooking up the LOC:
We used an LC2i per all of the discussion in the forums that a standard LOC would not handle the HK voltage. Splices from #1 went to the LC2i Factory Amp Outputs in photo. We pulled Power, Ground, and Remote from the amp to minimize wiring runs and ran the wires under the LC2i and amp.



For my application I am currently running an 8" Bazooka Tube I had laying around but the amp I used can also support something like the Earthquake SWS 8xi under seat sub direct replacements. With that option I could power the aftermarket 8" subs with a better amp and possibly get more sound with no lost trunk space and a cleaner look. I'm still undecided but the amp install should support anything similar to those options so hopefully this helps anyone new to the car looking to do a very basic level upgrade like I was.

[ntg44]

Great job. Thanks for this contribution.

[Mrfurious214]

Originally Posted by TCom

I picked up my 2018 M3 ZCP a few weeks ago and wanted to install a very basic sub setup into the car. One of the things I always find a little frustrating is finding some really basic info for best fuse to use for amp signal and which wires to hook a line out converter to. Here is what I learned from pulling info out of a few different discussions along with some photos I marked up. I hope will help others with this work.

1) Factory wires to get signal from:
Thanks to a post that had an italian picture the colors were the same and are the thick wires in the harness. We were able to splice into them without removing the trunk panel but did unplug all of the harnesses. This harness requires the housing to slide to the passenger side and then pulled out (was difficult by hand and pried out with tool)

Black/Red (Positive)
Black/Tan (Negative)
Blue/Red (Positive)
Blue/Tan (Negative)

Attachment 2472451

2) Fuse to get signal power from:
Next was finding a good switch power fuse to run the amp signal wire to. With a little trial and error and the paper diagram in the fuse box we settled on fuse 159 that corresponds to the radio. We ran a fuse connector off of 159 to the amp.

Attachment 2472447
Attachment 2472448
Attachment 2472449

3) Hooking up the LOC:
We used an LC2i per all of the discussion in the forums that a standard LOC would not handle the HK voltage. Splices from #1 went to the LC2i Factory Amp Outputs in photo. We pulled Power, Ground, and Remote from the amp to minimize wiring runs and ran the wires under the LC2i and amp.

Attachment 2472681

For my application I am currently running an 8" Bazooka Tube I had laying around but the amp I used can also support something like the Earthquake SWS 8xi under seat sub direct replacements. With that option I could power the aftermarket 8" subs with a better amp and possibly get more sound with no lost trunk space and a cleaner look. I'm still undecided but the amp install should support anything similar to those options so hopefully this helps anyone new to the car looking to do a very basic level upgrade like I was.

I spliced into the small black wire mixed in with all the speaker wires coming out of the OEM amp for power to my Alpine amp that powers my sub. Why not just do that?

[Encanto]

Originally Posted by Mrfurious214

I spliced into the small black wire mixed in with all the speaker wires coming out of the OEM amp for power to my Alpine amp that powers my sub. Why not just do that?

You mean, to remote turn on your amp or to fully power your amp? The first may be ok, the second is absurd and damaging.

[Mrfurious214]

Originally Posted by Encanto

You mean, to remote turn on your amp or to fully power your amp? The first may be ok, the second is absurd and damaging.

haha...yea just to remote turn on. power comes from the car battery

[Mrfurious214]

I have the HiFi audio system with the same Alpine amp and 2 8" Alpine sub's. I spliced off the OEM woofer wires just like you did but I'm not happy with the clarity of the bass though. Will an LCI2 help that issue or do I need to replace the entire OEM amp with something like a Bavsound amp?

[ellipsis212]

There's a great deal of information buried in the forum on how to add a sub. You need to decide if your solution is going to be clean and completely reversible to factory or you're going to cut/tap the oem amp wires. If it's available still the Technic PnP harness is the best solution and not expensive at all and IMO the first thing to get.

For amp turn on signal I would posi-tap the 12v acc in the trunk (idk if every car has that).

You absolutely need an active LOC for this system bc of the previously mentioned voltage. Audio Control LC2i is the standard.

[Tcgaylor]

I added my Kicker CXA1200 and Kicker Rcomp 12’s to the truck of my M3. The posts on here were very helpful. Thanks for that.
However, since the bass is processed, in the amp, and is not getting the lows I truly need, can this be done?

Split off of the Fiber Cables, pre-amp, let them continue to the amp but then feed as a secondary into the MoBridge DA converter, then out to my amp and subwoofer, for the true bass, I am looking for?

Has anyone tried this with success?

[Encanto]

Originally Posted by Tcgaylor

I added my Kicker CXA1200 and Kicker Rcomp 12’s to the truck of my M3. The posts on here were very helpful. Thanks for that.
However, since the bass is processed, in the amp, and is not getting the lows I truly need, can this be done?

Split off of the Fiber Cables, pre-amp, let them continue to the amp but then feed as a secondary into the MoBridge DA converter, then out to my amp and subwoofer, for the true bass, I am looking for?

Has anyone tried this with success?

The DA cannot share the same MOST address as the OEM amp. They cannot be installed together.

[Tcgaylor]

Originally Posted by Encanto

The DA cannot share the same MOST address as the OEM amp. They cannot be installed together.

Thanks Encanto. That’s is an absolute bummer. This system sounds good but not good enough. Definitely needs the lower levels and they lock it up so you can’t get them. ����

[Encanto]

Originally Posted by Tcgaylor

Thanks Encanto. That’s is an absolute bummer. This system sounds good but not good enough. Definitely needs the lower levels and they lock it up so you can’t get them. ����

You can "fill" the missing OEM amp bass frequencies with a Kicker KeyLoc.

[Tcgaylor]

Originally Posted by Encanto

You can "fill" the missing OEM amp bass frequencies with a Kicker KeyLoc.

You guys are absolutely correct in this post. Forget all the aftermarket OEM Amp swaps and speaker changes. The HK system has great sound but just needs that heavier bass.
I followed this conversation to the T, used the Audio Control LC2i and used a Kicker CXA1200.1, that I had from my truck. I had an enclosed sub that fit under the rear seats of my truck and that was the problem (enclosed.) I purchase a ported Kicker Rcomp 12 and put that baby in the trunk (boot!!) no more issues. All the bass is there. It is heavy, low and hits hard to all the rock music. Thanks all for the work in figuring this out and making it easy for everybody.

As for Hip Hop…. The cars next to you vibrate at the stoplight!!!

[tac3331]

Originally Posted by TCom

I picked up my 2018 M3 ZCP a few weeks ago and wanted to install a very basic sub setup into the car. One of the things I always find a little frustrating is finding some really basic info for best fuse to use for amp signal and which wires to hook a line out converter to. Here is what I learned from pulling info out of a few different discussions along with some photos I marked up. I hope will help others with this work.

1) Factory wires to get signal from:
Thanks to a post that had an italian picture the colors were the same and are the thick wires in the harness. We were able to splice into them without removing the trunk panel but did unplug all of the harnesses. This harness requires the housing to slide to the passenger side and then pulled out (was difficult by hand and pried out with tool)

Black/Red (Positive)
Black/Tan (Negative)
Blue/Red (Positive)
Blue/Tan (Negative)

Attachment 2472451

2) Fuse to get signal power from:
Next was finding a good switch power fuse to run the amp signal wire to. With a little trial and error and the paper diagram in the fuse box we settled on fuse 159 that corresponds to the radio. We ran a fuse connector off of 159 to the amp.

Attachment 2472447
Attachment 2472448
Attachment 2472449

3) Hooking up the LOC:
We used an LC2i per all of the discussion in the forums that a standard LOC would not handle the HK voltage. Splices from #1 went to the LC2i Factory Amp Outputs in photo. We pulled Power, Ground, and Remote from the amp to minimize wiring runs and ran the wires under the LC2i and amp.

Attachment 2472681

For my application I am currently running an 8" Bazooka Tube I had laying around but the amp I used can also support something like the Earthquake SWS 8xi under seat sub direct replacements. With that option I could power the aftermarket 8" subs with a better amp and possibly get more sound with no lost trunk space and a cleaner look. I'm still undecided but the amp install should support anything similar to those options so hopefully this helps anyone new to the car looking to do a very basic level upgrade like I was.

How did you mount amp to ceiling?

[NealfromNZ]

Originally Posted by tac3331

How did you mount amp to ceiling?

I’d use m4 rivnuts into the rear parcel shelve. Just be super careful when drilling the holes.