I'm interested in upgrading the audio electronics in my pcar. Although I'm sure that a complete system (head unit, amps, speakers, ect) would yield the best results I'd rather work with some of the existing components. I've learned that that the MOST system built into the 2002 1/2 and newer cars makes this very difficult due to the digital fiber optic link between the head unit and the amp. In addition the unusual impedance of the Bose speakers causes challenges. As I understand it the fronts are each 2 ohm, the rears are each 4 ohm, and the subs are 1 ohm. I am hoping that I could replace the amp in my car with a pre MOST system amp, still use the OEM speakers and just replace the head unit (Kenwood DNX 8120)

My Porsche dealer needs the part number off of a pre MOST system amp in order to insure that he orders the correct part. Hoping someone out there would be willing to read the number off there amp and post it here. Any other interesting or creative solutions to this dilemma?

A part number for the pre MOST amp and other ideas would be a great help. thanks.

 

I would rather spend the money on an exhaust... it sounds better.

 

Dealer? OMG.

I've been told, and have read, that there are aftermarket amps that will nicely drive the Bose low impedance speakers. AUdison and JL audio come to mind.

Find a shop that has done it before. Even if they aren't local they'll likely spend 5 minutes and point you in the right direction.

Going with Porsche, do you know for certain that the speakers pre 2003 are the same as the post 2003 speakers??? Buying a 2002 Amp may get you and amp that still doesnt work....

A

 

That was good!!!!hilari ous

 

ARD-

I'm fairly certain that the speakers pre and post MOST are the same...

Thanks for the aftermarket suggestions, I'll do some checking and see if I can get some answers.

Still hoping someone will get the part number off of there amp and post it here.

I can always return it to Porsche if it isn't compatible.

Cheers

 

I had my MOST system amp upgraded when I went to the AVIC-Z2.

Just go to a qualified car audio guy and they will take care of you.

 

Orlando333-
Did you leave the orginal speakers in or did you change them as well? What amp did you end up with?
Thanks.

 

Reply, left the original speakers in.

I went with a JL -- very good quality; mated well with the AVIC Z-2.

There are other viable options. Just remember, that you will have to mount the new amp somewhere, whether in the trunk or under the passenger seat.

 

Man, who do you know at the dealer?? At mine anything special order or electronic they allow returns.

I'm trying to decide on suspension or Audio/Nav system next...so I've been researhing as well. More than a few people have reported using aftermarket amps with stock drivers. Also getting info via PM and emails as I work through the project. Not near as concerned as I was when I started. Of course once you get the nice head and amp you'll still have those cheap Bose drivers to listen to. I am leaning toward new drivers too.

Good luck

A

 

I got lucky with a dealer connection. A friends, girlfriend's dad works there.

Orlando333- would you mind referring me to the shop that you used? I've been checking with all of the local guys and surprisingly none of them have mated an aftermarket amp to the Bose speakers. I'm looking for direction around the impedance issue.

I was considering the AVIC unit as well, it looks great. The current model Kenwood (DNX 8120) has bluetooth built into the double DIN chassis. One less box to install.

Thanks.

 

After a few months and numerous discussions with various "experts" Here is what I've discovered:

- After MY 2002 1/2 Porsche began using MOST bus system (fiber optic).
- Head unit replacement requires replacement of the amp (one 5 channel amp runs the OEM system, it's located next to the spare)
- The Bose speakers are 2 ohm, the Bose subs are also 2 ohm, but are wired in parallel and therefore in original configuration run at 1 ohm.
- There are very few amps that run stable at 1 ohm.
- You can re-wire the Bose subs in series and they will run as 4 ohm
- Your choice is to replace everything (head unit, amp, and speakers) and have full flexibility in the equipment and sound quality you want...
or
- Re-wire the sub woofers in series and just replace the head unit and amp. Sub woofer enclosure is easily removed by carefully pulling off the trim ring surrounding the ports from the top, exposing torx screws. When these are removed the whole enclosure slides forward.
- I ordered a pre-MOST system Porsche amp with the idea of a plug and play amp solution, however the connectors for these amps are not compatible and although you could retro fit a 2002 connector the amp isn't that good and is +/-$700.

My solution:

I run a B&B exhaust, good performance and sound, but loud, so I was not striving for great audio sound (I wouldn't be able to appreciate it over the exhaust note). I elected to leave in the Bose speakers, re-wire the subs to series and replace the amp and head unit. I found the Kenwood DNX 8120 http://www.kenwoodusa.com/Car_Entert...gation/DNX8120
head unit as currently best in class, and the Alpine PDX-5 (5 channel) http://www.alpine-usa.com/US-en/prod...hp?model=PDX-5 will run speakers (2 ohms) and subs (once they are re-wired) to 4 ohm. I chose the Alpine because it fits well in the location of the Porsche CD changer. There are better quality amps available but they are significantly larger and will eat up some of the precious cargo space.

This is a simple install because most of the necessary wiring (speaker and power) is already in place. The installer only has to feed line out cables from the new head unit through the firewall to the amp.

The GPS antenna fits nicely under the plastic bridge behind the alarm LED in the center of your dash. The Sat radio antenna (if you choose to add it) fits under the plastic cowl in front of the windshield wipers. This cowl has allowed for a good signal. The mic for the bluetooth phone application can be drilled into over head cowl. I think it fits best vertically centered just in back of the sunroof motor (there are 2 screws under the infrared security readers that hold the cowl in place. Remove these to see the location I'm describing). An alternate location and easier install (although I believe poorer performance because it is adjacent to the vent and will pick up the sound of heat or A/C air movement) is in the plug just to the right of the ignition. This plug pulls straight out.

The cable for I-Pod integration runs into the glove-box

I also found a wireless rear view camera that integrates nicely (not necessary, but this is supposed to be fun right?). Super easy to install if you provide it to you installer while he is installing the head unit. http://boyovta.com/products/vtx420.html no wires front rear bumper to front of the car. Power is connected up through the license plate lamps, into the engine bay, and over to the reverse lamps.

In my opinion regardless of the skills of an installer, the less dis-assembly the better. The Kenwood NAV, phone and Ipod interface, and GUI are excellent. The sound quality with the OEM speakers and the Alpine amp is clearly superior over stock and satisfactory for me given my application. If you are a true audiophile you will want to replace the speakers and subs.

If you want to upgrade everything this is the best solution I've found. Retain the OEM sub enclosure the Focal 13 KS subs http://www.focal-america.com/ are 5" subs fit perfectly. You can experiment with blocking or keeping open the ports (in the end sound is a preference). Sound connoisseurs will tell you that the enclosure is sub par due to it's plastic construction, I'm not convinced that's true. The Focal 130 KP are good speaker replacements and will fit with the OEM grills.

For better quality amps I would use the Genesis Profile Series. They are low profile and light weight. http://www.genesis-ice.com/. The 5 channel will fit in the place of the OEM CDC and extend over the black hump located at the center of the trunk. This black cover will need to be re-made 1.5" lower for the amp to fit under the hood. A qualified install shop can do this easily, but at some expense.


Hopefully this will save you the time, mis-direction and, and expense I have into what I thought was going to be a simple head unit exchange project.

 

Nice write up, thanks!

 

Nice write up TINS - exactly what I was looking for - except I was hoping I could just replace the head unit.

Do you have pictures of your install?

Thanks,
Paul

 

Good write upds TINS. Nice to know that.

 

If you're still around, can you give us an 8 year or so perspective on how you feel about your setup? And what things would you now do differently if you were starting over with todays current technology? The information you have already provided is much appreciated!