# Budget SQ in a Nissan 370Z + Spare Tire Retention



## simplicityinsound (Feb 2, 2007)

Hey gang,

As some of you may know, I used to work on a TON of 350zs...for a while it seemed like I was doing nothing but 350zs and G35s...rough estimate is that over the years, I have touched about 35-40 of each model lol...it got to the point that I stopped going to those car forums because it was getting a bit repetitive. 

So now, it’s been over a year since my last Z, and finally, I get to lay my hands on a new 370Z...a car I have wanted to do since it was released since it seems to be much better suited for sound quality than the old model.

This car came in on a pretty low budget, and was suppose to receive just a simple passive front and sub layout, but after giving it some thought to the fact that it’s my first 370Z...I decided to donate a Zapco DSP6-SL to the build... at the time of this post, the customer still has no idea that he’s getting a active system with a DSP, hopefully he doesn't visit this forum, or else the surprise will be ruined haha 

Anyway, onto the goals:

1. Achieve a decent level of sound quality, this is not a comp car, just clean daily listening as the stock system is TERRIBLE!

2. Build a clean looking design in the hatch with ZERO loss of trunk space...not about being showy here...just sturdy and usable.

3. retain the OEM spare tire and have the ability to access it with relative ease

Obviously, the last two design criteria presented the biggest challenge...as we didn’t want to raise the floor at all...

Let’s get started:


The signal source starts with a customer supplied Alpine INA-W910 navigation headunit, it is installed in the stock location with the Metra kit:










The Alpine USB extension is routed to the cubby above the headunit, the supplied IPod adapter allows the customer to play either a USB drive or iPod/iPhone:










The customer also supplied me with a pretty cool back up camera that is designed to go in place of the rear passenger side license plate light...it snaps into place just like the OEM piece, still retains the light, and adds a low profile camera:




























As the car uses a Zapco DSP6, all tuning is done from the front seat via a laptop:


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## simplicityinsound (Feb 2, 2007)

The front stage consists of a set of Focal Polyglass 165 V30 6.5" two way component set. This 30th anniversary model is a step up on the normal 165VR. The tweeters were mounted into baffles cut to match the stock "tweeter" baskets:










and mounted to the stock location at the top corners of the dash...this to me is a much better stock location than the tiny sail panel of the 350z:



















The 6.5" midbass went into the stock lower door locations, and new speaker wires were run into the door through the stock molex plug:










Here again the 370 makes it easier than the 350z, with big blank section in the plug that can be drilled out to pass the wires through and there is no window jutting down behind the speaker opening to cut into the mounting depths:










New baffles were fabricated for the midbass and coated with truck bedliner to protect them against the elements:










The door was then sound proofed and the baffle installed via stock bolts:










Here is a close up of the V30 midbass:


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## simplicityinsound (Feb 2, 2007)

The speaker installed into the door:



















The same procedure was repeated on the driver side door:





































Here are some pics of the wiring bundles as they go from the front to the back of the car:


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## simplicityinsound (Feb 2, 2007)

Moving onto the trunk, so here is the view with everything covered up, as you can see, the hatch looks pretty much 100 percent stock, the stock carpet still fits and the rings for cargo tie down are still exposed, overall height in case is around 1/4", basically from the thickness of the new fake floor:



















Remove the carpet and here is what you see, a new fake floor wrapped in black trunk liner, divided into four sections, with two cutouts.


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## simplicityinsound (Feb 2, 2007)

remove the two covers and here is what you see, two Arc Audio's new Xdi mini full range class D amps sit at the front, a 804 sends 80 watts a piece to the mids and tweeters, and a 1000.1 powers the sub with 700 watts at 2ohm. The sub is a Stereo Integrity BM MKIII.

The amps were chosen for their price point and more importantly, their tiny footprint, as they had to go into a unused space ahead of the strut brace area. the sub was chosen for its shallow mounting and its ability to work in TINY sealed enclosures. both the amps and the sub are trimmed in black CF for a lil visual pop. But again, things are dictated by functionality, not showiness.
































































Now you may noticed the four screw covers on the center section of the fake floor, they hide four bolts...and this leads to the system's little party trick, remove those four bolts and the center top floor panel comes out:


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## simplicityinsound (Feb 2, 2007)

then you are left with the sub enclosure itself...which then can be lifted out to have full access to the spare tire. The side panels also release with Velcro and two screws each to access the tools if need be:










I timed myself and the entire process takes under 2 minutes and requires nothing more than a Philips screw driver. There is also enough extension on the subbox to rest it on the hatch opening:










This is a pretty weird view I guess of a sub enclosure 










The enclosure is about .4-.45 cubic foot, which may sound small but the Si really have very little problem with it, as you will see later.

onto the build pics.

First I made the flat portion of the enclosure that matches the contours of the OEM foam spacer’s bottom side, and then cut a hole that is a little smaller than the spare tire rim size.










next, this is the bottom portion of the enclosure that sits inside of the spare tire rim...speaking of which, maybe I should go into business making MDF brake rotors? lol



















Fleece was then stapled the outer edge of the piece:


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## simplicityinsound (Feb 2, 2007)

then it was put into the wheel, and the fleece pulled and stapled to the inner edge of the flat mdf baffle. After this picture was taken, a 50 lb weight was dropped onto the center piece to pull the fleece tight, and resin applied:










Now the reason why I didn’t just take a profile mold of the inside of the spare tire well is because I want to have a little bit of wiggle room so the enclosure can slide forward and lift out of the trunk easily.

Once the resin cured, the entire thing was lifted out of the car, and a few strips of wood to act as bracing/support were secured:










Next, the inside of the fleece received a dozen layers of fiberglass mat to reinforce it, the center hole sealed off, and speaker cables fed in:










Here is the enclosure from the bottom:










Next the top mounting baffle was fabricated to match the OEM foam spacer's topside profile:










and the two pieces mated to form a single enclosure. I lined the bottom of the enclosure with foam to prevent any buzzing and rattling against the spare tire rim:



















the top baffle was then covered with black CF vinyl, and now the enclosure is ready to be dropped into the car:


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## simplicityinsound (Feb 2, 2007)

Moving onto the amp and processor. As mentioned, there is a strip of wasted space at the front of the hatch area, previous occupied by a single foam spacer. Once that was removed, I was left with a wide but short strip of real estate. First an mdf board was secured with stock bolts and nuts and provides the mounting point for the Zapco DSP6.



















Next a top board was secured and the Arc Audio XDi amps were mounted and wired up:










I can tell you that bending over the high hatch opening to do the mounting and wiring was one of the more painful experiences of my installation career lol.

Here is the cosmetic trim for the amps before and after vinyl application, and then put into the vehicle:




























The front fake floor before and after carpet:



















The two side panels:


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## simplicityinsound (Feb 2, 2007)

and the center fake floor portion:



















Also the grilles for the amps and the sub:





































So that’s it...after some tuning by my friend Scott Welch, the car sounds pretty good...overall tonality is nice and smooth, with good detail and midbass impact. Stage for some reason is absurdly high...like rear view mirror high lol, decent width, depth was okay considering the stock locations and shallow dash, and center is pretty decent as well. The SI BM MKIII continues to impress as without any tuning, it presented us with a very smooth and flat response from 80hz down…with no real peaks and valleys…this is a 12” sub in a .4 cub feet enclosure!!! Sub bass to midbss transition is not too bad either…not as good as say the dodge ram I did recently, but not bad. Overall, I think it’s a nice sounding car given the relatively modest budget. 

An hour’s worth of tuning gave us this EQ curve on the RTA, the light rise at the bottom is from the sub turned up, not part of the sub response itself 










So yeah, that’s my first 370Z...in many ways this is a better car for audio than the 350Z...and I noticed it’s put together much better and there were almost no audible rattles. The interior doesn’t come apart as easily and working on the amps upfront is very tiring, but overall...pretty cool! 

Cheers,

Bing


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## [email protected] (Jun 12, 2008)

Nice work as usual, beautiful car. That was very nice of you to donate that to the build.


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## nednerbf (Jun 24, 2011)

Really like the look of this build. Just clean an simple nothing over the top.


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## screamatamonkey (May 15, 2009)

Excellent job as always!

Btw, what is your opinion on those ARC amps? How do they compare to other amps in their class (Alpine's PDX, JL's HD, etc) for running a front stage?


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## 94VG30DE (Nov 28, 2007)

Gotta love a Z with spare tire retention. Yours looks a lot cleaner than my job did


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## simplicityinsound (Feb 2, 2007)

screamatamonkey said:


> Excellent job as always!
> 
> Btw, what is your opinion on those ARC amps? How do they compare to other amps in their class (Alpine's PDX, JL's HD, etc) for running a front stage?


these amps arent in the same class as PDX or HD, they are at a much lower price point. i would say the one amp that best compares with them are the JL XD amps...

so far, on initial impression, they are very comparable...good clean power in a tidy small package. are these as good as bigger class A/B units? prolly not, but for a project like this they work great


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## Bluenote (Aug 29, 2008)

That's a great install Bing, as well as a Great gesture to your customer by donating the DSP! Your the Man!


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## cnut334 (Oct 17, 2009)

Nice and clean install on the Z! Good job.


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## eviling (Apr 14, 2010)

i swear to god one of these mods have it out for me..my posts are constantly dispearing O_O 

i posted - 

is that sub really that special? you use it allot i noticed. it seems to require an extremely tiny amount of space too looks nice too.


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## JayinMI (Oct 18, 2008)

screamatamonkey said:


> Excellent job as always!
> 
> Btw, what is your opinion on those ARC amps? How do they compare to other amps in their class (Alpine's PDX, JL's HD, etc) for running a front stage?


We've been doing a few of these lately. I've been pretty impressed. Good volume, decent sound (better than the XD JL amps), no noticeable noise issues and super pricing. We sell the Xdi805 for like $299ish...for that, it's brain dead. I think they sound better than the original PDX's, but I haven't heard any of the new PDX amps. As a matter of fact I have a BMW M3 Vert in the garage that's got an Xdi805 and will be getting an ARC 10 IB.

Jay


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## simplicityinsound (Feb 2, 2007)

eviling said:


> i swear to god one of these mods have it out for me..my posts are constantly dispearing O_O
> 
> i posted -
> 
> is that sub really that special? you use it allot i noticed. it seems to require an extremely tiny amount of space too looks nice too.



well, i have installed a total of 4 of these subs including this one...so i wouldnt call it "alot" hehe but thats not really my choice...they are just not that easy to come by

but to me, yes, looking at the rta curve...i dont know of any other sub that offers this combination of characteristics:

1. under $300

2. actually works in a sealed enclosure below .5 cub feet

3. have actually pretty decent ouput and extension

4. is less than 3.5" deep for mounting depths.

and the small box is the key thing here...

if only Si did a real dealer account thing and produced more, you would see me doing a ton of them as they suit my style quite well hehe

b


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## wdemetrius1 (Aug 16, 2007)

Another great install.


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## robolop (Mar 10, 2008)

Very nicely done, and very clean finish.


:thumbsup::thumbsup::thumbsup:


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## JayinMI (Oct 18, 2008)

Bing,

Did you have any problems with the Focals? The first set I did (a couple of weeks ago), if I put any significant pressure on the terminal block, it came off the basket. The connections were a little tight, but not outrageously so. Seemed that the adhesive they used wasn't very strong. I glued them back on and all was well and they sounded very nice.

Jay


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## eviling (Apr 14, 2010)

simplicityinsound said:


> well, i have installed a total of 4 of these subs including this one...so i wouldnt call it "alot" hehe but thats not really my choice...they are just not that easy to come by
> 
> but to me, yes, looking at the rta curve...i dont know of any other sub that offers this combination of characteristics:
> 
> ...


nice. i was just looking at your box, you stacked a bunch of 1" MDF rings it looks like. i was wondering how you got such good curves and perfectly round tehe. very nice job. I wish i had 1\10th the skill you have  i want to do a false floor in my trunk, come out to allentown!


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## simplicityinsound (Feb 2, 2007)

JayinMI said:


> Bing,
> 
> Did you have any problems with the Focals? The first set I did (a couple of weeks ago), if I put any significant pressure on the terminal block, it came off the basket. The connections were a little tight, but not outrageously so. Seemed that the adhesive they used wasn't very strong. I glued them back on and all was well and they sounded very nice.
> 
> Jay


nada on this one...i have had that issue with a few speakers over the years...but this focal was pretty rock solid, i managed to bend one of the spade terminals and the one on the basket didnt even budget.


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## EcotecRacer (Sep 16, 2008)

Bing what do you think of those XDi amps by Arc Audio? thinking of using them in my Solstice GPX cause of their size and power


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## simplicityinsound (Feb 2, 2007)

eviling said:


> nice. i was just looking at your box, you stacked a bunch of 1" MDF rings it looks like. i was wondering how you got such good curves and perfectly round tehe. very nice job. I wish i had 1\10th the skill you have  i want to do a false floor in my trunk, come out to allentown!


its still mostly fleece, the only part that is a stacked ring is the part that sits above the hub portion of the spare tire rim and clears the lock down mechanism.  the rest is just a bottom part and a top part with fleece pulled in between.

i used to live a hours away from allentown..."well we're living here in allentown, and they're closing all the factories down.."


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## simplicityinsound (Feb 2, 2007)

EcotecRacer said:


> Bing what do you think of those XDi amps by Arc Audio? thinking of using them in my Solstice GPX cause of their size and power



i usually dont like to make an instant judgement on amps, becuase unlike speakers, unless they FAIL in some spectacular fashion right off the bat, its hard for me to get a totally accurate reading on the product from one install.

i can tell you that they look nice, are small, and didnt detract from the overall sound quality, and are very well placed on the price/watt scale. Based on this, i have no problem using it again in projects that require tiny amps and/or on a budget. For small amps like this, my biggest concern is always with heat dissipation, but so far so good, playing in the 104 degree garage with the car off for a coupla hours didnt seem to do too much to them.


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## eighty5iv (Aug 15, 2010)

Amazing and beautiful work as always.


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## butdamnbrian (Oct 3, 2010)

loving the setup bing put together for me! i've been away from my car since the build finished so i've only been able to play with it for one day!

just thought i'd drop by to list a few noteworthy things bing didn't note in his write-up that round out the details:

1. axxess steering wheel integration

2. powered fan mounted to cross-cool amps and processor

3. head unit sub level control (works v. well with the 910 hu)

4. bluetooth mic mounted above mirror, nav antenna mounted under dash

5. appropriate fuses mounted on battery under-hood

6. zapco processor's usb cable wired through glovebox for laptop tuning (which i have no idea how to do haha) 

superb work bing! i'm thrilled man..


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## killahsharksjc (Apr 30, 2009)

Nice job Bing.... clean and simple.... how did the 30th An's sound compared to the originals????


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## simplicityinsound (Feb 2, 2007)

i dont have enough experience with them back to back to say, these were pretty decent, especially for their price range


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## veritasz34 (Jul 25, 2011)

Very nice job. I really like the stealthness of this install. I hope to do a stealth one in my next project. BUT I don't have to worry about keeping the spare..My camaro didn't come with one..


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## justfuz (Aug 28, 2008)

Install looks great Bing. I really enjoy following whatever you work on. I noticed you used the same metal grating for the sub & amps that you did on the vette install. what type of mesh is it? Any place specific you get it from?


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## simplicityinsound (Feb 2, 2007)

its just perforated steel mesh from mcmaster.com you can choose the thickness and open area.

if you want to do decorative mesh, then best to get aluminum or paint the mesh, the steel rusts...found out the hardway...


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## TJ Mobile Audio (May 6, 2009)

94VG30DE said:


> Gotta love a Z with spare tire retention. Yours looks a lot cleaner than my job did


As I recall, we designed your box around _not_ using fiberglass, lol...


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## CGMMNY (Jul 26, 2011)

Bing, 

Do you recall the stock bolt sizes you used to secure the amp rack. I'm in the middle of building a rack in the same open space of my Z. 

Thanks!


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## Scooby (Feb 23, 2008)

That is some nice work!

Is the fiberglass layed over the MDF just to give it more strength?

Please advise when you're coming to Missouri. I want to be first on the list.


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## jab4au (May 31, 2010)

Great job Bing, as always! I really like the OEM/stealth look of your installs. Thanks for always posting your builds. I always walk away with new ideas!


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## simplicityinsound (Feb 2, 2007)

CGMMNY said:


> Bing,
> 
> Do you recall the stock bolt sizes you used to secure the amp rack. I'm in the middle of building a rack in the same open space of my Z.
> 
> Thanks!


crap you know what i dont...just pop off one of those nuts on the studs...and take it to the hardware store.


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## simplicityinsound (Feb 2, 2007)

Scooby said:


> That is some nice work!
> 
> Is the fiberglass layed over the MDF just to give it more strength?
> 
> Please advise when you're coming to Missouri. I want to be first on the list.


yeah, the one part where the glass is laid over the wood in the middle ,its only 1/2" mdf. i needed as much mounting depths as possible to keep the box stock height.


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## jaikai (Aug 8, 2011)

Excellent craftsmanship. Very nice.


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## Frank Drebin (May 30, 2011)

Always enjoy your build threads.


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## pnn23 (Jun 7, 2008)

Bing would you happen to remember the brand/model of that backup camera?


Lookin' great as usual. About par for the course :thumbsup:


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## simplicityinsound (Feb 2, 2007)

Brian supplied it...PM him...he is butdamnbrian from above


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## KyngHype (Sep 7, 2009)

Great work as usual, my gf can recognize your installs from looking over my shoulder lol


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## simplicityinsound (Feb 2, 2007)

lol...nice! vegas huh? 4 more months and Im there!


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## KyngHype (Sep 7, 2009)

simplicityinsound said:


> lol...nice! vegas huh? 4 more months and Im there!


lol Yep, you're coming New Years? Always fun here..


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## Old Skewl (May 30, 2011)

Nice clean install. Love the stealthiness of it! Sub enclosure is awesome. Used to have a 91TT and had to give up some hatch space using a JL stealthbox.


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## simplicityinsound (Feb 2, 2007)

KyngHype said:


> lol Yep, you're coming New Years? Always fun here..


i go every year for CES. early january.


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## SSexpo03 (Jul 30, 2010)

Another nice job Bing, congrats!


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## shawnk (Jan 11, 2010)

Nice excecution on that enclosure!

Form and function at it's finest!


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## butdamnbrian (Oct 3, 2010)

pnn23 said:


> Bing would you happen to remember the brand/model of that backup camera?
> 
> 
> Lookin' great as usual. About par for the course :thumbsup:


the camera i bought online is actually one made for the nissan livina, but it's interchangeable with many other nissan models (including the 370z, luckily!).

Color CMOS/CCD Car Rear View Camera for Nissan Livina
Part No. Q01276

I picked mine up on tmart.com, but you can also search e-bay for "nissan livina rear view camera" and a bunch will show up.

i'm sure it's of lower quality compared to name brand cameras, but shoot.. at $23 (shipping included), i can always grab another if this one dies on me.

bing hope all is well, man! i finally have my car again and am loving the install!


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## Arclight (Apr 29, 2011)

Great install... this has to be one of my favorites on the forum as it's stealthy but executed in a classy way (that doesn't detract from the car). 

I'm going to have to look up some of your other installs now.


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## Ronin69 (Mar 29, 2015)

Very cool. I like the space saving install and the tuning.


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