MKIII to MKIV Upgrade

[Dazmeister]

Hi,

Hoping you guys can enlighten me...

I purchased my 2001 E46 with a MKIII CD unit about 6 months ago but frustrated at the speed with which it updates (even after software upgrade). I have noticed a big difference in my friends M3 with DVD unit, so have been trying to source a MKiV unit for some time.
Found one recently on eBay and couldnt resist bidding as it was going for a bargain. Description of item was not specific, so I guess a lot of people missed it on search. Anyhow, bit concerned that the unit might not be compatible as the front panel is different to what I have normally seen. It has a Power on and CD-IN indicator to the right The majority of the units I have seen only have a Power on indicator on the left of the facia.
I asked for Part no. but all he could supply was FD09004360220475
Said it came out of a 04 (2004 model) 7 Series. Not seen a pic of the rear of the unit.

Any help appreciated


Darrin

[UCrewX5]

That drive is for a MOST-bus based 5 and 7 series, and will unfortunately not work in i-bus based vehicles such as the e46 (3 series) or e53 (X5)

[Dazmeister]

So I take it there is no modifcation you can make? I assumed the same unit was fitted to all BMW's. You learn something new every day...

[UCrewX5]

Originally Posted by Dazmeister

So I take it there is no modifcation you can make? I assumed the same unit was fitted to all BMW's. You learn something new every day...

Unfortunately, no, there is no modifications that can be made. The MOST-bus is an optical system, whereas the i-bus is much much much (did I say much?) slower electrical based system. They don't even speak the same language.

The reason the ones for the MOST-bus are so much cheaper is the basic principle of supply and demand. All MOST-bus nav drives were DVD based, so you don't have owners out there trying to upgrade to one. Rather, the only real demand for the MOST drives is from owners that have had one fail and are out of warranty (which isn't very many at this point). On the flip side, the MkIV drives for the i-bus based vehicles (e38, e39, e46 and e53) are in demand because you have a lot of owners of vehicles with MkI, MkII and MkIII systems that want to upgrade to a fast drive that can have use DVD's instead of CD's.

Sorry for the bad news.

[Dazmeister]

Thanks for the comprehensive reply. Its interesting to know the differences in speed. So if I were to get hold of a MOST-bus unit, would I then also need the headunit (plusloom incorporating optical lead) or is it not that simple? As if I am going to upgrade to a faster system...but I guess as its new technology the head unit will be expensive.

Is there anymore information on the later technology?

[Dazmeister]

From what I understand after doing some digging, it would also require the changing of the cd-changer which would also be connected by fibre. Is this correct?

[UCrewX5]

Keep in mind that the i-bus is what drives communiction for all non-engine and non-safety (ie. airbags, etc.) components. Likewise, the MOST-bus does the same in the newer BMW's. So, it's not just a simple task of putting in a head unit and nav drive. Rather, you are talking about reengineering the complete communications of the vehicle. Not recommended.

You'll be miles ahead just to find an i-bus MkIV and paying the price for it, trust me.

[Dazmeister]

Thanks,
I completely understand now, its all sinking into place.

Still reluctant on spending $600 (£350) on a MKiV unit but guess I would make some money back on my MKIII.


Thanks again for the information.