[jeffbrig]

I'm nearing the completion of my DIY gut & replace of the stereo in my Cayman, and I'm going to try to document the details for any other intrepid souls that are thinking of doing this themselves. My aim here is twofold - better sound quality (I was never happy with the Bose equipment) as well as bringing the car into the 21st century with BT, Nav, etc.

First...yes it's been a lot of work spread over the last few weekends. First thing worth noting - a Porsche does not come apart as easily as other cars I've worked on - those Germans really don't want you messin' with their stuff. My background - I'm just a handy guy, engineer by day, who has installed quite a few stereo systems back in my high school days.

The equipment list:
Pioneer AVH-4200NEX head unit
JL Audio HD900/5 amplifier
JL Audio C5-653 3-way components (front)
JL Audio C2-400x coaxials (rear)
JL Audio Stealthbox (13TW5) subwoofer
AUTO-VOX CMD24 backup camera
MicroBypass Parking Brake Switch
KnuKonceptz wiring
Ebay installation kit (seller: autoware302)

Here's the patient before surgery:

Here's most everything laid out before I got started...

(much) more to come...

 

[jeffbrig]

First, let's talk about how I selected the pieces I ended up with.

Head Unit - I've always been partial to the tuners in Pioneer radios, but my primary motivation this time was their integration with Google. The NEX radios support App Radio mode, and even google voice commands when connected with a cable. Not sure if I'll really use this feature, but it steered me towards their products. The 4200 was the highest tier modem without going to units with built-in NAV (at a substantial premium). With a $100 rebate, I got the head unit for around $400.

Subwoofer - I picked this up from the classifieds some time back, and it sat on a shelf in the garage while I've been waiting to get the rest of the project going. I've built many subwoofer boxes for other cars, but the Cayman shape and storage options doesn't lend itself to plywood/mdf boxes. Rather than have something custom fiberglass formed in the car, the JL stealthbox was the obvious solution, and buying used means a reasonable price.

Amplifier - Probably the toughest decision. Going with a Class D amp is obviously prefereable (mandatory?) in such a small car. I know most on here go for a 6 channel and try to drive the factory subwoofer and/or 8" door speakers, either in parallel or with resistors. I couldn't see myself doing that with the Bose speakers, so once I resolved to get 3-way components I only needed 4 channels + 1 for the sub. I considered (agonized?) over many amplifier options, but consistently found the HD900/5 mentioned as the best Class D available - it is JL's flagship amplifier. I also considered the Alpine PDX-V9, as well as other JL options: XD700/5, or even an XD500/3 with the head unit driving the rear speakers. In the end I came across a non-working HD900/5 on Ebay, which I took a gamble on. Thought I might take it apart and find something obvious that I could fix. Nope. So I sent it in for service, JL replaced the internals, and for ~$400 total I ended up with a factory refurbished HD900/5 with a warranty.

Speakers - This was actually pretty easy. Since I already had a JL sub and amp, I felt it made sense to stick with the same brand for speakers. The 3-ways were easy, as the C5-653 is the only set JL makes. Rears were also pretty easy - but you have to go down to the C2 line to find a 4" speaker that will fit in the rear. It's just rear fill, so not a big deal. One note on 3-way speakers....the spacing between the door mounted midrange and dash mounted tweeter is not ideal, but it's what Porsche gave us. I'm not keen on cutting or surface mounting a black tweeter in the door panel, so I'm sticking with those locations. The key is making them fit (more in a future post).

Backup camera - Not strictly necessary, but if you've got the panels off and you're running subwoofer wire to the trunk, why not snake some extra cables and mount a camera? I picked the model I did because it has a tiny connector from the camera side of the cable to feed into the car. I figured if there was any chance of having to drill I wanted a tiny hole. I ended up pulling the wire through the taillight opening, and size was absolutely not a factor. So don't worry about that if you are picking out a camera - any size connector on the cable will be fine.

Microbypass (for parking brake) - some may question whether this is a wise choice. I have no intention of watching video or really even using he screen while driving. But when I have a passenger, I don't mind them being able to pair a phone, enter a nav destination, or use any number of menus/options that the unit disables when the parking brake is off. It's flat out easier to bypass it and let the thing work. And, it saves you the work of tapping additional wires under the center console.

Wiring - I've always liked KnuKonceptz for offering quality cables for a reasonable price. Ordered 4 gauge for the amp, although the runs are so short I could have gotten away with less. But 4 gauge is a better fit for connecting at the battery terminal and amp terminals, so I went with 4. KnuKonceptz Collosal Flex is aptly named, it's a 4 ga cable that you can coil around your wrist - crazy flexible cable. Also bought 12 gauge speaker wire for the sub, and 16 gauge for everything else.

Installation kit - went with an Ebay seller that seemed to have a decent looking kit, with Bose connectors. I was on the fence about pulling my own wire vs tapping into the Bose harness in the boot, so I wanted to get a kit that gave me that option. More on that later.

more coming...

 

[jeffbrig]

On to the install!

For whatever reason, I started with the backup camera first. I had a big leg up in that the rear shock tower covers were already removed from my car. I installed coilovers a while back, and deliberately left these off because I knew I'd be changing the rear speakers, and snaking wires to the back.

I started by removing the license plate. I figured I could figure out a way to pull the wire without removing the bumper, and that's exactly what I did.

The hole behind the plate is for the tow hook, but works great for hiding the cable.


This picture is looking behind the bumper cover, with the taillight removed. If you look very closely, you'll see a hint of light behind the plate area, that's where the hole is. I used a straightened dry-cleaning coat hanger as a snake to pull the wire to the taillight.

Here's the camera after the wire was pulled.

 

[jeffbrig]

Okay, gonna pause now....photobucket is apparently not good for image linking anymore....is anyone seeing the ones I posted so far?

 

[danschy]

Okay, gonna pause now....photobucket is apparently not good for image linking anymore....is anyone seeing the ones I posted so far?

Not me, just get the Photobucket ransom demand.

 

[T-Design]

Okay, gonna pause now....photobucket is apparently not good for image linking anymore....is anyone seeing the ones I posted so far?

nope .......

 

[jeffbrig]

Not me, just get the Photobucket ransom demand.

Thanks for confirming. I was seeing the pics originally, probably because my browser cached them.... now I'm seeing the ransom demand too. I'll host 'em elsewhere and fix the links when I get a chance...

 

[jeffbrig]

Continuing with the backup camera install....

So here's the taillight connector where I needed to tap into the wire for the reverse light. While I was here, I also tapped into one of the parking lights for the head unit illumination wire. Note that the pins are conveniently numbered on the connector, so there is no ambiguity. The reverse light is #3, and the illumination is #6 (I will confirm in my notes tonight and edit if those aren't the right ones).

The camera needs a ground, so i used this factory grounding point behind the trunk lining. This shot is looking in through the hole where the taillight would go - it's by far the easiest way to access everything.

One of the questions I asked myself when installing the camera was whether or not to wire in a relay and bring power from the battery instead of placing the additional load on the backup lighting circuit. While I was bench testing the unit, I pulled out my multimeter to measure the current draw of the camera when operating. For this camera, it was a measly 45 milliamps. Meanwhile, the 21W light bulb pulls almost 2amps (2000 miiliamps). So that told me there is really no reason to run a relay, unless you really just want to hear the tiny click each time it is activated.

One other convenient feature of the camera I bought was that its 12V wire is available at both ends of the cable. It's intended to simplify installation by letting you connect to power at either end. Feeling rather sneaky, I used this to my advantage by tapping into the reverse light in the back, and using the other end at the head unit to signal when the car is in reverse. Why not? No extra cable to snake.

Pulling the wires down the driver's side of the car was a right pain-in-the-***, even with my trunk area open. To lift the door sill, there are two hidden bolts that you must loosen, but not remove. If you look down in the gap between the sill and the driver's seat, you'll notice two tiny black plugs. You have to remove those, and then there are hidden Allen head bolts underneath. You have no idea what size they are (don't remember exactly, but you're looking at 4-5mm sizes), and you have to find them by Braile. No need to remove them completely, just loosen. Then pull straight up (use a plastic prying tool if needed) to get the clips to release. If it doesn't release relatively easily, loosen the bolts are little more.

Once you get the door sills up, you realize that Porsche created some really nice cable chases down the edge of the car, and there's already a large bundle of wire running through it. Because I was a dummy and had already soldered up the connections at the radio plug, I couldn't pass the camera video connector through the case, but I was able to tuck it underneath. I also ran the 12 gauge subwoofer wire through the chase (pictured) while I was in here. The silver piece is my grabber/snake tool.

Then, with the carpeted panel and trim removed, it goes up around the seat belt mechanism and into the trunk. The grey foam is easily manipulated, and you can follow the other bundle of wires up into the trunk area and zip tie everything well - you don't want a stray wire to interfere with the seat belt mechanism.

 

[jeffbrig]

Now for my favorite part - speakers.

I knew this was going to be tricky, because the Bose system has a bunch of 3.5" speakers, and I'm replacing with 4". I kinda took a leap of faith that I'd be able to sort out the mounting details. Hey, I'm an engineer - I solve problems for a living, right?

First the rear speakers...

A side by side of the old and new. I'll let you guess which is which.

Yes, that is a cheap, paper cone, full-range speaker. Ugh. In a German car, with the expensive Bose option box checked (there was no Burmeister in 2006, Bose was it).

As far as installation, the speaker grille is large enough to support a 4" speaker, but it's not a flat mounting surface. The Bose uses a smaller speaker, with a larger plastic ring around it that mates to the unevenness. I like to think they do this to increase the difficulty factor and discourage people from doing what I'm doing.

Because these are undermount speakers, I ended up using a ring of thick weather stripping foam around the front perimeter of the speaker frame, and was able to get a good seal, and the speaker cone can safely move without rubbing anything. No pics of that, as it's rather difficult to show.

You'll also notice that Bose proprietary wiring connector on the back of the speaker. I de-soldered the wires, and with an exacto knife and much cursing, I was able to liberate them from the Bose speakers, and create my own adapters. No cutting of the factoring wiring harness for me!

Yes, by doing this, I committed myself to reusing the factory wiring. Generally, I'm the type that will snake new wiring throughout the car, even into the doors. But after careful consideration and looking at the sizes of the wiring, I decided it was just MUCH easier to go with what's already there. I measured the resistance of the wiring to each speaker, and found values from .02Ohm (door bass speakers) to .04Ohm (rears), which says "good enough". The wires running the rear and the door midrange are DIN 1.0 mm, which falls between 16 and 18 gauge awg. The 16 ga I would have pulled was not enough of a difference maker to justify the work.

 

[jeffbrig]

Next up, dash tweeters...

First, how to get the old ones out without marring the soft touch paint on the speaker grille. Paperclip! Straighten one end, put a kink at the end, and put it through one of the holes in the factory grille. Give it a swift tug, and it pops up in the front.

The factory tweeter is held in with clips on two sides. I used a couple of small screwdrivers to spread the clips and managed to wiggle it free. Next, you have to consider wiring. In a Bose car, the tweeter in the dash and the midrange in the door are on the same set of wires (verified with my multimeter). With my 3-way set and its passive crossovers, they need to be on separate wires. Running wires to the dash is easier than running wires to the doors, so I put new ones here. Nothing magical, you just have to snake them down to the footwell. Worry about routing them through the firewall and into the frunk later...

The foam you see in the dash is my addition. The JL tweeter would not reuse the stock mount, and I didn't see any other good alternative. So it's a piece of foam to the rescue. Then it's pressed down by the grille, holding everything securely in place.

Voila....

 

[jeffbrig]

Next up, door speakers...

First the 6.5" woofers in the C5-653 kit.

It may not look it in that photo, but the Bose speaker is ~7.9", and my new ones are 6.5", so they're not exactly a straight drop in. I have to fabricate a mounting plate. After a lot of thought, I decided I wanted to try to salvage the plastic baskets that the Bose speakers nestle into. They're ABS plastic, they hit all the mounting points in the doors, and they're smartly shrouded with louvers in the back to shield the speaker from water (doors are a wet environment). So I need to make a plate that could mount in the 7.9" opening, and cut a smaller hole in the middle matching the diameter of the new speaker. And I need to add depth - about one inch. Interestingly, the center pole piece of the Bose speaker projects out a full inch, so there appears to be room under the speaker grille in the door panel.

My go-to material for this is HDPE (high-density polyethylene plastic). It's sold under the trade name Starboard, and it's rather expensive sold as a sheet. But it's also what's used to make plastic cutting boards...which you can buy for peanuts at any number of home goods stores. I also have a buddy with a CNC machine, so we fired up the software and cut some really slick rings to mount the speakers. With two layers stacked, it adds exactly inch of thickness.

Perfect, right?

Not so fast. While the depth works, the shroud on the door panel makes an airtight seal around the ring of the woofer. That shroud does not like the extra depth of the mounting rings I added. So, I need to make my mounting rings smaller - at least for the portion that sticks out. Router to the rescue. The top ring was reduced to the diameter of the speaker roughly 6.5". The lower ring was reduced, but only about half of its depth so it would sit flush with the ABS plastic basket. I'm not gonna lie, getting this part figured out was tedious. And routing plastic makes a HUGE mess, lol...

Here's what I ended up with. This works - there's enough clearance for the door panel to lay flat.

Then, fully mounted and wired. The Bose speaker had the terminals on the front, so I had to drill and pass my wires inside, and sealed with RTV silicone. Also put RTV between the layers to make sure we're air tight.

 

[jeffbrig]

And the midrange.

Pretty straightforward here...I used foam weatherstripping again to seal the face of the driver to the mounting ring on the door panel. Depth was not an issue. I used another of the connectors I had put together to connect everything.

There were no clearance issues. One thing I did like seeing is that the door panel is constructed so that it completely isolates the woofer and the midrange. They do not share airspace, which is a good thing.

 

[jeffbrig]

A couple of notes about removing the interior door panels...

There are several good videos on youtube showing how to gain access to and remove the 5 bolts, door release, etc. But getting the snap-locks off is tricky. There are 9 in each door, around the sides and bottom edge. I spent close to an hour on the first door, and broke one of them. I spent 10 minutes doing the other door, and all of them came of easily.

So, here's my advice...if you're having trouble getting these to release, grab a panel tool with a forked edge - the thicker the better. Think of it as a forked wedge. Lay under the door, pry back the panel a bit (use another panel tool), and with a flashlight/headlamp, locate the offending snap-lock. Get the forked panel tool in there, and use it as a wedge to pop it open so it releases. I did this on the second door on a what was threatening to be a problematic fastener, and had it off in minutes.

Next piece of advice, remove these snap-lock fasteners from the door panel, and DO NOT put them back on until you have dry fit everything and verified the door panel can seat fully and you have clearance for the new speakers. You do not want to connect and reconnect these multiple times. I had the panel on and off half a dozen times checking fit while making my speaker mounts.

Make sure that all of the snap-lock fasteners are fully in the open position before you attempt to reinstall the panel. The "pin" should be fully retracted into the "collar". Most of mine released when they came out, but a few had to be reset. I used two forked panel tools from opposite sides to pop the remaining ones open.

Here's what one looks like in the fully "open" position.

In better news, I just finished a sound check, and everything checked out. The head unit still needs to get put into the dash (and cables managed, not looking forward to that headache), and then I need to permanently mount the amplifier in the frunk. Should be able to do all of this tomorrow and have the car back on the road.

More updates coming tomorrow...

 

[jeffbrig]

This may belong in a separate thread eventually, but I'll throw it in here as part of the project.

My biggest annoyance with the Cayman interior has to be the flaking paint on the AC rocker switches. Drove me nuts. While I had the stereo out, I couldn't pass up the opportunity to do something about it. So I removed the AC control unit, disassembled the face, and removed the rocker switches. There's a good video on youtube that shows how to do it. Then I took to cleaning every bit of that peeling soft-touch paint off of the plastic switch. I started by scraping what I could with a small flat screwdriver. But that still left a bunch of greasy residue. I found that Dawn dish soap and a scrub brush worked quite well. Probably took 20 minutes or so to get down to clean white plastic. I wanted it clean and smooth so the new paint would go on well.

Then I needed a way to hold them for spraypainting. I simply rolled up a sheet of paper and taped the switches to it. Then shot with a can of flat black spray paint that I had in the garage. Note that I gave up the fan and temperature icons that were on the buttons, but mine had turned to big white patches already.

Time will tell as far as durability, but they look 100x better right now.

On reassembly, it's worth noting that there is a left and a right switch. They taper slightly towards the outside, so make sure to figure out which is which before putting them back in. With everything reassembled and back in the car, here's how they look. This shot also shows the paint match of the bezel that came with the radio install kit I bought on Ebay.

 

[jeffbrig]

Next we start pulling wires together in the frunk for the amplifier installation.

Here's the new "add-on" battery terminal that allows me to add the amp wiring without modifying the car's positive clamp. It clamps to the battery, then has a screwed in "battery post" that the car can be connected to. You can also see the inline fuse holder. Note that the power cable runs separate from the speaker wires (blue), and RCAs (grey).

 

[TomAZP9]

Jeff, great Post with pics! Where did you end up sourcing the Battery Terminal Add-On to retain OEM positive cable?

Tom

 

[jeffbrig]

Where did you end up sourcing the Battery Terminal Add-On to retain OEM positive cable?

Tom, it's all from knukonceptz. It's a great idea to not have to cut the factory cable, but figuring out the best way to install it took a little thinking. For the interstate battery that's in my car, the post does not sit proud of the battery top - it's recessed and blocked in on two sides. The orientation I used is the only way you can set it up and have access to the clamp screws. The terminal has threads to mount the add-on post on top or on either side. I ruled the top out as being too tall, and one side is blocked by the battery. So I ended up with what you see there. You'll notice the car's pos wire is clamped onto the very end of the post - that's necessary so you can still turn the nut to clamp it.

Bassik Positive Battery Terminal - Merchandise
Top Post Adapter - Positive - Merchandise

 

[jeffbrig]

Continuing on with the install...

One drawback of gutting a Bose system is that the old subwoofer has to stay in the car, otherwise it'll look like this:

Yep, the carpet is cut, so the subwoofer has to remain in the car. I'm not one for carrying around unnecessary weight, so I removed the amplifier and speaker from the Bose sub before putting the shell back in place.

Which gave me the opportunity to capture this rather hilarious side by side comparison...

 

[jeffbrig]

Next, a look at getting wires from the cab to the frunk.

If you're standing at the front of the car, looking into the open frunk, there's an unused (uncut) grommet right next to the right edge of the battery. You don't have to remove the battery, but if you loose the holder and slide it left, you can get access to it easily enough. I cut an X in this grommet, and used my handy coat-hanger to push through the insulation into the car. Then I did a similar X cut of the insulation in the driver's footwell, and started pulling cables through.

Here's the grommet from the front:

And here's where it comes out in the footwell:

Ok, so that gets you into the "exterior" battery compartment. Then there's a second grommet you need to get through to get inside the frunk compartment. The obvious choice here is another unused grommet on the left side of that wall. Behind where the OEM CD changer mounts, just above the evap canister (or whatever the heck that box is in there). Here is what it looks like with the plastic compartment removed.

You can see that I cut another X in this grommet and started pulling wires through. Now, key point, you do NOT want to run the power cable through with your RCAs, unless you enjoy the high pitched screech of alternator whine. So, I drilled a 3/8" hole through the adjacent grommet and passed only the power cable through that one. When everything is done, I plan to smear some RTV sealant on these grommets to make sure no water can seep through.

As far as routing wires, I also tried to avoid coupling my RCAs with any other wires. So, they take a path in front of and below the battery tray. The speaker and remote turn on wires are routed under the cowling behind the battery - I plan to wrap these in split loom to offer some protection, and zip tie where appropriate.

 

[jeffbrig]

Next comes the speaker crossovers and connecting to the Bose wiring harness.

I prefer solder to crimps, so here are the 6 pairs of speaker wires I need. 2 rears, 2 door woofers, 2 door mids.

And now inside the frunk

The wires run up in the right hand corner, following the factory wiring, then across to where the crossovers will mount in the little compartment. Remember, all of the wiring will be covered once the panels are back in place.

And with the crossovers all wired up

To mount the crossovers, I simply put some Velcro patches on the back. They aren't going anywhere, but can be removed if needed.