Kilowatt Cobra Stereo Install

[rattle_snake]

The Mach 460 sound system is OK if you don’t care about quality, capability or attitude, kind of like a V6 in a Mustang (2004 V6 at that). The system has a few drawbacks including;
-No aux audio input (can be had with SAT input adapter for $75)
-No USB interface. Can’t use front panel control at browse files
-Bass response weak after ½ way up
-High frequency response dry at best, 2” paper cone HF drivers just don’t cut it
Upgrading just the head or speakers/amps will add additional cost to get adapters to make the separate pieces work so it’s easier and not much more expensive to start completely over.
An additional benefit to running a high current circuit to the trunk is future support for things like a BAP and a nitrous bottle heater. These 2 items need 50 amps alone.
Now there are douches out there that will quickly point out that muscle cars don’t need stereos, they only add weight, and that the cash should be spent under the hood. I disagree; I like my music loud and I think it’s a great complement to an authoritative exhaust note and blower wine to share with those around me.
Here’s my equipment list;
Punch P500-1bd 706W into 1 ohm
Punch P400-4 246W x 2 bridged into 4 ohms
Punch P3D2-10 10” dual 2 ohm VC sub
Power T1652-S 6.5” separates

Step 1 is to gut the interior as needed and add some sound deadening material. My FTBR solid IRS bushings transmit gear noise very well and it annoying as hell. Anything helps. 315 wide rubber is noisy too.

The factory 5x7 door location will accept a 6.5 round speaker, barely, and will require a custom adapter plate. I use ¼ hardwood ply. I sealed the adapter plate to the plastic mount with RTV to reduce vibration. The door is a horrible speaker box, no point in trying to improve as the driver will have a high pass filter anyway. The door panel sealed against the face of the old speaker and will contact the surround of the new one so it must be trimmed.

The upper door speaker housing is modified to accept the RF tweeter. This is fairly simple but critical to performance. Spend the time to get this right. The goal is to aim them on-axis or as close as possible. This is more difficult for the driver side.

At this point I have most of the wiring run and the door speakers in. Next step is to fabricate a board to mount the amps on, then the sub box.

 

[03 DSG Snake]

Looking forward to the rest. I'm about to tear out my 460 as well.

 

[03 SVT COBRA]

Subscribing

 

[rattle_snake]

Power wiring

One of my goals with this install it to not hack up the car. I want to be able to remove everything and put the old Mach system back in at some point. I was going to use these plated brass terminal but didn't want to hack up the factory wiring.

So I just added a 1/0 gauge ground in parallel with the existing little 12 gauge wire. I just put a nut in the back of the factory terminal. The ground point on the chassis has a captive nut so I used it instead of drilling a 5/16" hole and sanding the paint off. The kep style terminal underneath has teeth that penetrated the paint and dig into the new 1/0 terminal so it stayed were it was.

The best location to get through the firewall on the left side is here. I didn't want to chafe the wiring so I removed the plug so I could see what I was doing. I drilled a hole with a 90 deg adapter and a step bit. A little soap and the big wire pulled though a little hole in the grommet. cover in split loom and it blends in with the factory hydraulic lines

I mounted the giant wafer fuse holder beneath the fuse box. This holds a single 150A fuse. I left the wire to the battery off, this is the very last thing to connect.

 

[rattle_snake]

Amplifier Rack Part 1

This will be the home of the amps and filters. These hole presents a problem and a solution. The problem is that they let road noise into the cabin. the trunk has basically no sound deadening. The solution is that the pressure from the sub can pass though. My plan is to obstruct the higher frequency sound with the amp rack itself and some dampening material. The surface is not flat but the factory box can be used for guidance.
Note that there is carpet over the 'tweeter' high freq. driver.....

I made a template out of cardboard including the locations of the 6 factory mounting studs that will be used to mount the amp rack. this will also make a nice cover to protect the speaker for storage.

Here's the equipment laid out on the template to transfer to a piece of 3/4 MDF

The MDF is cut to shape and the mounting holes drilled (not easy to get all 6 within 1/8") and cutouts for 2 bolts at the top of the back seat. I wanted to mount the amps with the wiring facing the front of the car but it will be very difficult to access it that way. They will have to go the other way.

To mount the new mounting studs a t-nut is recessed on the top of the mdf. this holds them in and a 6 nuts can be tightened from the top after all the stuff is mounted to the carpeted rack

 

[Jmccormick]

looking awesome!

 

[Jefe]

beautiful equipment! Have you listened to those 6.5s without the sub? Curious how the bass is

 

[rattle_snake]

Amp rack part 2

I removed some material to reduce weight

Covered the MDF with carpet and installed the amps and filters in pre-drilled holes

Power distribution blocks and 4ga DC wiring

The top of the rack is covered with 2 layers of Dacron. This is my attempt at a mechanical low pass acoustic filter. It also prevents vibration between the MDF and metal rear deck.

 

[Jmccormick]

looking good man!

 

[rattle_snake]

Sub box

The enclosure is a 0.7 cu ft sealed wedge constructed from 3/4 MDF to fit the angle of the back seat. Outside dimensions are 11" tall, 18" wide and 6"/11" deep.

Interior walls are lined with Dacron. Fiberglass is slightly better but is a pain to work with. This is done to absorb standing waves. The wedge shape is actually much more effective at deflecting standing waves as the baffle and rear wall are not parallel.

Carpet is glued on. Not my favorite thing to do but a quality job necessary or it looks like crap. Sub's dual 2 ohm coils are wired in parallel and then run out to the terminal to present a 1 ohm load to the single channel sub amp.

Test fit in the trunk. Doesn't take up much space. Plenty of room for a nitrous bottle and groceries. A dual banana plug is used for quick disconnect. still need to add a strap to hold it in place.

I made some corrections to this system that are minor but important:
1) Changed the parallel wiring scheme from a 'daisy chain' to a 'home run'. Daisy chain is wiring the terminal to the 1st coil and then the 1st coil to the 2nd. The home run version is wiring both coils directly to the terminal, and each wire has only 1/2 the current.
2) I originally installed the sub and terminal cup over the carpet, and was not confident that it was properly sealed. I cut the carpet off the sealing surfaces of the box. For the sub I added a thin strip of rubber/butyl gasket material because the odd shape of the speaker couldn't really be trimmed to fit right. Now I know it doesn't leak at all.

 

[03 DSG Snake]

What does that amp rack weigh?

 

[rattle_snake]

What does that amp rack weigh?

Rack itself is 7 lbs. With amps and wiring the assembly is about 27 lbs.
The sub and enclosure weighs in at a hefty 32 lbs
The Mach 460 plastic rear speaker box is 23 lbs.

I added a few pounds of sound deadening material so total weight gain is <40 lbs. Because it's all over the rear 'axle' it may help traction in 1st and 2nd gear quite possibly making the car quicker from 0-75mph... then slower above that.

 

[rattle_snake]

Amp rack install

I added some additional sound deadening mat similar to what is found on the trunk mat over the wheel wells and on the forward trunk floor.

The 1/0 ground wire is grounded with a 5/16" bolt and a toothed kep washer after the paint was ground off

The rack is mounted and the studs tightened up. From the top the Dacron can be seen filling the holes in the read deck.

Wired up and ready to test/tune

I mounted a LED Mag light in the trunk. Mounting screws bite into some 1/4 oak.

 

[Jmccormick]

very clean install.

 

[rattle_snake]

Head unit install

I went with a relatively cheap Sony head unit. I wanted the following features and this unit has them all for $120; (CDXGT565UP)
-USB input with artist/title display.
-dual RCA out/ sub level control
-wireless remote
-decent user interface. I like the Sony over the Alpine and Pioneer at this time. I have owned them all over the years.
This deck also has a programmable LED color option that allow the factory gauge green color to be matched pretty well.
I have another Sony deck in my truck (CDX?550?) and it can only access 4GB with it's USB interface. I hope this one can access 8 or 16.

I used a metra dash kit (99-5027?) for a single DIN. I ditched the metal sleeve and mounted the deck in the dash kit with 4 screws on the side. To use the Metra trim ring I needed to flush mount the deck in the dash kit so I made some relief cuts in the sides

I modified the rear support bracket of the kit to support the deck and to re-use the factory rear mount in the dash. I cut a piece of aluminum and attached the factory bracket with a countersunk machine screw.

The new assembly mounts in the dash same as the factory deck. The Metra trim ring looks much better that the Sony one.

Not finished tuning but sounds alright. having and issue with bridging the P400-4 so just using 2 channels for now. The sub sounds very good and can move enough air to massage your scalp. folding down one of the seats results in about a +6db increase in output so my mechanical filter isn't preforming quite how I want. I need to add some spacers between the amp rack and the metal rear deck to allow more pressure to get through. The front separates sound OK, they are not anything special. I have some high end MB quarts in the truck and they are far superior to these Rockford units.

The dash lights defiantly dim when the bass hits so I guess I need a capacitor in the trunk. The alternator is probably marginal for this system but I don't leave it cranked up long enough for it to really be a problem. I need my hearing to function for another 30 years.

 

[SBTerminator]

Looks great, very clean. But as you already set, the gear you used is not up to par with the install and or sound quality. I have 2 sets of MB Quart Q's waiting to get installed this spring along with a JL300/4, and a JL 500/1 powering a 10W7. Only thing I haven't picked yet is my headunit.

 

[rattle_snake]

My wife does some work for Rockford so I got everything but the deck at employee cost. The Power series P1652-S were only $56. I have a little over $550 in the whole thing.
Being a audio snob, yes at some point the seperates up front will have to get upgraded.

I replaced a JL 10W6 with a Punch P3 shallow in my truck and was surpised at how well it sounds. and for only $45.

 

[rattle_snake]

With the Mach 460 enclosure removed this unfinished area is ugly;

So I made a cover out of 1/4 press board and a strip of MDF to contact the flap of carpet that hangs down. it is secured with nuts to some existing 6mm bolts

looking better

This is how the sub is secured to the car. The nylon strap wraps the LATCH bar beneath. I modified a plastic clamp to screw to the box. Easily removable for the drag strip with just this strap and the banana plug.

 

[rattle_snake]

Capacitor install

I added a 1.5 Farad cap in the trunk to deal with the disco headlights. The cap is wired with the same 1/0 awg wire as it will have even higher currents than a system without a cap. A cold beer is used to facilitate installation.

The cap is mounted next to the fuel pump controller. I have no need for the digital voltage readout so it went behind the panel. The ground on the cap is critical to is performance. Make sure the cap is wired between the load (amps) and the source (alternator/battery) as the current goes into the cap and back out to the load.
The purpose of the cap is to hold the voltage stable at the amplifiers. The side effect of the lights not dimming is that the current transients come from the cap instead of the battery.

Edit: Think of the beer glass as the cap and the tap hose as the alternator output (everyone has a keg setup, dont they?). The extra storage capacity local to your mouth allows for a big gulp of suds, even though the keg has gallons of beer in it. If you drink enough beer it will all make sense.

 

[NorCal_03Cobra]

This all looks fantastic, great work! By far one of the cleanest installs I've seen