Wednesday, October 7, 2020

Modernizing the Stereo, Part 4 - Wiring

So this post will be about all the wiring I had to do to upgrade the stereo to a true hifi system.  If you remember, Nismo Omori Factory had told me that Worx had stripped out the OEM wiring harness for the front door speakers, so in addition to the cables for the new DSP amp, the wiring from the head unit to the amp, the speaker wiring from the amp to the speakers, I had to deal with removal of substandard wiring in the doors, as you will see.

First, the wiring/cabling for the amp. Here in Japan it is near impossible to find, at least at the consumer level, 1/0 AWG OFC wire, so I ended up ordering from the US what I thought was more than enough to handle the power and ground cables. 

As you can see I also ordered lots of speaker cable - the dark blue - as well as some 4 AWG power cables in both red and blue. 

As you saw in my last post, a lot of the effort was to make sure I was able to properly mount the amp, the distribution block, and the main fuse holder.

But once done:

I decided to go ahead and make it look more professional by adding some PET cable wrap protection - although to be honest I'm not sure how much protection these cables need given their location in the trunk (versus being in the engine bay for most other cars with a front mounted battery - protection from heat and fluids is more relevant there).

Green arrow shows me starting to add the wrap

And solid black for the ground cable

After wrapping both it looked like this:
Green arrows show power cables wrapped; red arrow is the lead I made for the CTEK charger; and pink is showing where the power cable from the battery would plug into the main fuse holder

And then of course I went ahead and tested to make sure there was enough clearance (I also checked how the inner trunk lining fit - no problem there either, just no photo at this stage:

No problem! Right? Well except because I had chosen to use these battery terminals - they are unique in that they clamp directly onto the battery terminals and allow attachment of various size cables but also via side posts allow you to attach the OEM battery cables directly - - all great except it requires the cables to be attached from the front side of the battery - meaning it turns out that the length I ordered for the power cable was JUST a bit too short (see pink arrow two photos up). 

So I did what a reasonable person would do, I managed to find a 1 meter length of 1/0 AWG here in Japan from a specialty store (but it cost me over 3000 yen!) and ordered it... but while waiting for it, I decided to go ahead so I decided to finish laying the speaker wires.

This too, was a miscalculation - in order to run speaker wires for an active component system, I realized I should use DIFFERENT colored wires to differentiate the wiring for the tweeters and for the midrange woofers up front. So, I went ahead and ordered the wiring on the left - same 14 AWG gauge and OFC of course (see technical note below - yes total overkill on the speaker and learn...). And yeah, this is what happens when you order when tired and sleepy... the new wiring (on left is ALSO blue but luckily its ground cable is black).

I realized then that I had better take a look at the wiring that Nakamua at Worx had done to the door speakers, to see how I would pass these wires.  I was in for a shock.  

It started out OK. I started with the passenger side door and had reached inside the doors to see how the existing speaker wires were wired back into the car body. It all looked relatively normal at this point:

But I soon realized something was off:

Door side connector - what is that thick black wire?


So yes friends, Nakamura at WORX had decided that this was the only way to pass his new speaker wiring into the doors.

What to do...I called Nismo Omori and this part is no longer available...

Ok. After calming down and reading on the Internet car audio forums that this seemed to be an acceptable way of passing UPGRADED speaker wires into the doors...

14 AWG wire on the bottom - top 4 wires installed by Worx seems
to be about 20 or 22 AWG each (same as OEM?) 

I again almost had a stroke after seeing that the bulk of Nakamura's wiring was all insulation and filler! The actual wire core diameter is not much bigger than OEM. So he basically drilled the hole to pass an ADDITIONAL small core wire that he then wired BACK into the same speaker terminals. If not for that extra wire he could have used the OEM speaker wiring.

Technical note - I have learned that the reason for thicker speaker wire is to prevent voltage drop over long distances (due to resistance).  

Given the relative low power of the Pioneer CyberNavi deck, and the close distance of this head unit to the doors, I am honestly STILL not sure why that second wire was necessary.  Why not stick with the OEM connectors? Instead of drilling, could he not have simply upgraded the wires to a higher quality wire of the same gauge? OR, if you are going to go to the trouble to drill out the OEM connectors - why not use one single thicker wire? Passing another OEM size gauge wire makes absolutely no sense.

Being a realist as well as an optimist, I decided to see if that existing hole could handle the two 14 AWG speaker, but quickly realized this was not going to work.

Way too thick to pass through the holes, even where I used a file to make the holes just a tiny bit larger

Given that I was running 14 AWG speaker wire right up to the area in the body right next to the doors, I decided to see if I could run thinner wire in the doors only, to minimize the voltage drop I referenced above.

So, another delay as I had to order some 18 AWG car audio speaker wire, this time from Audio Technica Japan:

Again, for some reason it is blue...with silver

But at least I got two of them to fit through the existing connector holes. Ensuring I can run my tweeters and midrange actively from the DSP amp.

Of course, I had to repeat this exercise on the drivers side... which was worse because Nakamura drilled TWO holes into the connectors...

I went back under the dash and figured out what that second wire was for - the wiring for the red and white LEDs that fade out with the interior courtesy lamp that I installed in the door a while back - not sure why it wasn't present on the left side door. 
And while I was at it, I labelled everything not OEM (green tabs)

Gotta say, I did enjoy REMOVING Nakamura's wiring however:
SNIP! I cut and removed this from inside the door

And this one from inside the body:

Anyway, I finished this side in only 45 minutes (about 4 hours on the left side given trying to figure out what to do) and then as the Alpine components still hadn't arrived, it was time to move onto hooking up the 14 AWG speaker wires to the amp and laying it in the car.

I didn't know better, but after watching some videos I thought that ferrules would be good for these type connectors that plug into the amp.  I later found out I was wrong, but for now they seem to be doing a decent job.

You can see the tweeter wires on the right, with the black ground cable

I hooked up the two sets of cables to the amp:

And then ran them to the side and behind the amp, being careful not to block the amp's cooling abilities as well as the OEM cables there.

By loosely but carefully running these speaker wires - passenger side along the left, drivers side on the right, following the OEM wiring but NOT trying to disguise them as OEM, I was able to finally lay them out close enough to the doors, tying them loosely (temporarily) with red zip ties.

After that, I just soldered the 14 AWG wires to their respective 18 AWG wires on each side, making sure I didn't melt anything in the kickpanel area. While I was at it, I tried to clean up the wiring in the center stack. Note I did what I could with that random red power wire with fuse (for the boost controller... it also had a lead coming out for the ETC reader).

The car looked like this for about two weeks:

But as I finished up (after tightening up all the zip ties, double and triple checking for clearance, etc), it looked it like this:
Green: the DSP amp; light blue: drivers side speaker cables ; orange: USB cable and remote control cord from amp; red: the "speedwire" from the head unit; pink: bundled cables (speedwire and left side passenger cables) with the OEM wire bundle; and yellow arrow showing these wires bundled with OEM harness

So other than the door connectors, a relatively smooth install. I took pain to make sure people could spot the non OEM wiring, so used plenty of red and white zipties. 

So now I'm ready for the front speakers... but still no Alpine components - SonicElectronics sent me the WRONG product (I got the coaxials... again) so I had to order the components from another retailer, requesting expedited delivery. Oh well... meanwhile on to the rear speakers and deck!


Anonymous said...

This makes me especially glad that it seems like my R33 has not had any modifications to the stereo...

Aki said...

Count yourself lucky!

VspecR said...

Wow this has been a amazing journey, I have been reading all all of this from start to finish.