# E90 M3 Add-A-Sub Install (lots of pics)



## G8RM3 (Apr 2, 2015)

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E90 M3 Add-A-Sub Install (lots of pics)

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So this post will serve partially as an introduction to the forums as well as a log of my add-a-sub install.

A couple of months ago I was fortunate enough to purchase a 2011 E90 M3 that was spec'd with all the options I was looking for. This car is an absolute dream! Since then, I have been lurking on the forums for miscellaneous topics, one of which was adding a sub to the EPS system.

I do love the way the EPS sounds from factory, don't get me wrong, but similar to many others I was hoping for a little more sub-bass. Enter the forums and some very helpful forum members. So thank you to those who contribute to the discussions on these boards. They are very helpful!

All in all, the installation process was very smooth. Once I compiled all of my research and ordered all the parts I needed, it was easy to install. Having access to everything you need in the trunk is very helpful as well. I'm going to try and walk through the process and include pictures of some things that I could have found useful during my research. Hopefully it helps.

First things first: the car






The first part of the process was getting all of the misc. parts/connnectors together. This included Technic's PnP harness and LC2i, in-line fuse holder for LC2i, 12AWG power/ground wire, 18AWG remote wire, industrial strength velcro, cloth/friction tape, quick disconnect connector for subwoofer enclosure, BMW OEM battery connector parts, and 4AWG amp wiring kit (KnuKonceptz from Amazon).


The OEM battery connector parts can be found at this link:http://www.realoem.com/bmw/showparts.do?model=VA93&mospid=50624&btnr=61_1946&hg=61&fg=30

F-type connector for larger wire (used for 4AWG power wire to JL Amp):



F-type connector for smaller wire (used for 12 AWG power wire to LC2i):


Single pole housing for 4AWG power wire. Your distribution block may have different slots open. So make sure you check it out and confirm that the open slot has a metal pin installed already (did this by using a small mirror to look up inside the distribution block to see metal pin)


The first thing I wired up was the LC2i. I decided to mount it right next to the OEM amp as that location would keep it hidden and allow for easy adjustments. I made a small mounting adapter out of extra MDF and painted it black. I then velcro'd the adapter to the OEM amp rack and then velcro'd the LC2i to the adapter. I was careful to make sure I had enough room on either side of the LC2i to plug in wires without being impeded by the OEM amp rack. 




I ran the 12 AWG power wire for the LC2i along the OEM harnesses from the battery side to the amp side. I ran the RCAs and remote leads with the OEM harness as well, trying to keep everything tucked in nicely and using zip ties and friction tape where necessary. I grounded the LC2i to the OEM ground location as well (note the black wire coming out from under the OEM ground cluster).


The remote turn on lead was run for the LC2i based on this tutorial from VP Electricity. It was very helpful and wire was pretty easy to find. Unfortunately I forgot to take pictures of this part. EPS Remote Turn on Lead- VP Electricity

The next step was to install the Technic PnP harness and plug in the LC2i to it. I PM'd Technic via his thread (Technic PnP EPS Harness) and ordered the harness/LC2i from him. His response was prompt and helpful, giving me unsolicited tips and references to additional information. He shipped the package out to me the day I paid as well. Great customer service experience! The harness quality seems to be top notch and I was fully anticipating a very quick and easy install with it. However, for some reason when I tried to install the PnP harness to the OEM harness, I could not get the sliding clip to lock properly:


I did everything I could think of doing to try and re-align the pins and try again but for some reason the clip would just keep derailing. I contacted Technic about it and he was very helpful with giving me suggestions on how to fix it. Nonetheless, I still could not get it to latch. So Technic kept working with me to get it right and after a few more tries, I wound up just snapping the clip shut with a set of channel locks. After that I inspected the connector to see if anything looked out of the ordinary but all looked good. Not sure what the issue was here but just wanted to post it incase someone else runs into the problem. Also, I wanted to give a shout out to Technic for working with me on this issue and helping me get it resolved.

The harness then plugged right up and latched easily to the OEM harness. All was good.

I did want to note a little trick that helped me get the pesky sliding clip unlatched on the OEM plug at the amp. If you try and slide the clip to the right to unlatch it, it can be difficult to do with your hands because it is on there tightly. Plus there is limited room to work with. What I found works great is slide it to the right slightly, just enough so you can stick a small flat-head screw driver through the clip and pry agains the connector to slide the clip all the way to the right. This step made taking the OEM connector off the amp a breeze.


Now that the LC2i was installed and the remote leads run, it was time to install the amp. I purchased a JL JX500/1d amp to power a JL 10W3V3-2 sub (500W RMS @ 2ohm). The JX amp is very nice as it's small and fits perfectly in the empty spot underneath the floorboard (I believe this spot is where they used to put the satellite radio tuners). Again, I used the industrial strength velcro to fasten it to the floor. The fit is like it was meant to go there. 


I then installed the 4AWG power wire for the amp. I crimped and soldered the 4AWG wire to the F-type connector above (p/n 61136920094) and then inserted it into the single pole housing (p/n 61136925176). The final result:


I then velcro'd the 4AWG in-line fuse holder to the back wall of the car and ran the power wire along the OEM harness back to the amp. Here's how the battery connections look like. Notice the in-line fuse holder for the LC2i as well:




Due to the amp's location, I could not reach the OEM grounding points with the amount of ground wire provided in my kit. Also, I am not a fan of having ground runs on amps any longer than 3 feet, if it can be helped. As such, I checked one of the mounting bolts that the OEM nav unit uses as a possible grounding spot. After a successful test, I decided to go ahead and ground the amp to one of these bolts as they are right next to the amp. Only needed about 6" of ground wire. 


Next it was time to turn my attention to the meat of the install&#8230;the sub!

The first step was to find a suitable enclosure. I did not want to lose any meaningful trunk space so a corner loaded enclosure was a must. From my research, there are really only 2 commercially produced enclosures that fit this bill for the E90, 1) Musicar NW and 2) Wicked CAS. Of the two, I much preferred the look and fit of the Musicar enclosure. From pictures and reviews I saw, it seemed to be the least invasive and high quality. I spoke with Musicar on purchasing a box unloaded but just did not have the budget for purchasing a new one. The CAS box was looking to be the best option.

Prior to purchasing the enclosure I spent quite a bit of time searching the forums and CL to try and locate a used enclosure (they don't pop up much). Luckily, I found a member on another M3 forum selling a 10" fiberglass enclosure that did not fit in his e46 M3. He wasn't sure exactly which model it would fit but by looking a several pictures and comparing with Musicar's enclosure, I thought it had to be what I was looking for&#8230;a used E90 10" enclosure made by Musicar NW! I purchased it on a hunch that it would fit and sure enough, it fit like a glove! I was stoked.

The shell of the enclosure was in great shape, but the carpeting was in pretty rough condition. Not sure what happened to it but it had been picked pretty badly. Lots of carpet fuzz on it. Here is the enclosure in the condition that I bought it in:




In order to fix the carpet and get it looking new, I attacked it with a razor blade and a fabric defuzzer (like the one your mom used to use to get all of the picks off of your wool clothes). I cut away the long fuzz with the razor blade and then went back over it with the defuzzer. It worked awesome! The carpet looks great again.






Next, I had to re-organize the speaker wires in the enclosure. The enclosure came with a 4 conductor speaker harness but I did not need that since my sub was single voice coil. Inside the enclosure, I twisted the leads together and tinned them for connection with the sub's terminals.



Coming out of the enclosure, the original harness terminated in a 4-pin molex connector. Again, I did not need the 4 pins, so I cut the molex off and installed my own quick disconnect connector.

Now, the subwoofer/speaker quick disconnect is a topic I spent a lot of time researching because I wanted a connector that was 1) robust with high current rating (>45A), and 2) a little more elegant than typical spade connectors. To be honest it was difficult to find what people are using as a solution for this type of connection. Sure you can use Molex plugs but I was a little weary about some of the amperage ratings I saw on them. My research led me a lot of places but I finally settled on these connectors: http://www.castlecreations.com/products/castle_connectors.html

They are made by Castle and are designed for the R/C industry to connect batteries to ESCs and other high-current applications. I used the 4.0mm connectors which are good up to 70A! They have larger diameter connectors good for 200A as well (way overkill here). These little R/C connectors are perfect for the application, if you ask me. There are other types/colors/sizes as well. They do require soldering the wire to the connectors but it's not difficult to do if you own a soldering iron (or want to buy one for $8).

Female connection on the enclosure:



Male connection on the speaker wire from the amp:






I decided to go with a JL 10W3V3-2 sub. Due to the sealed trunk space on these cars, I knew I would need a little extra power in order to be able to get the effect in the cabin that I wanted. 500W seemed to be the right number, so I went with this over a 10W0. I did not see it necessary to go with a W6, so the W3 was perfect and within budget.

Here it is installed in the enclosure:


The enclosure fit in the car like a glove. There were some wide strips of Velcro already on the back of the enclosure so I left them there to help keep it in place. Not really sure that the enclosure would need it though. At some point, I may fab up a small bracket to keep it there but for the time being, I think it's not going anywhere. Of course prior to putting all of the panels back in I started the radio to ensure everything was turning on and the sub was working. No issues!

I will note that one thing I'm not overly fond of is with the remote lead I used, the amp and LC2i stay on for quite a bit (prob 3-5 minutes after all the car doors and trunk are shut), they then come back on as soon as a door is opened. So you don't have to have the radio/acces./ignition on for the amp and LC2i to be on. I guess it's not a concern of draining your battery unless you leave your car doors open for a considerable amount of time without the engine running. But something to think about.

Here's a shot of everything wired up and the trunk liners put back in. 


And the amp and LC2i disappear: 


Leaving you with an awesome looking sub in a great looking enclosure!


The enclosure hardly sticks out into the trunk space as well:




Overall I'm very pleased with the install and the way everything came together. I have to give a big thank you to Technic, VP Electricity and this forum for all of the help!

I can't give a great review on the sound yet because for one the sub is still breaking in and I have not gotten a chance to give it a proper tune. As of now though, I can hardly tell that the sub is even there when I'm at higher volumes. The bass seems to come through a little better at lower volumes. I will be playing with the tune a little this week and see if I can get it dialed in. I'm certainly not looking for overwhelming bass, but I do want to get it a little louder than it currently is. I know it will sound great once I get it there though!

Also, for those of you planning your systems and trying to stay on a budget, maybe this will be helpful. I was able to find great deals on a lot of the products I got. The biggest help was the used enclosure and savings on the amp. Overall not too bad for the level of equipment that I got!


I hope this post may help someone in the future with their install. And if you have made it this far in this epic saga of a post then kudos to you!


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## Fooljam (Oct 2, 2007)

Nicely done and documented well done :thumbup:


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## CDA325i (Jun 15, 2015)

Great install and beautiful car!! My only thoughts are your "lack of bass" (termed lightly) could be because it struggles to get from the trunk to the cabin. Do you think that is the case? I didn't have a ski pass in my car and had to make one. When the back seat arm rest is up, I barely have any bass. And when it is down, look out! I could be totally wrong. Just my .02 and something to think about since it is not mentioned.


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## kancerus (Sep 22, 2017)

Any chance of getting access to your install photos? They aren't visible in here anymore and photobucket says the library is private!


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