Q7 ramblings

[Ti Kan]

Dave Eaton writes:
> #3: people have been warning about overcomplication and the expense of
> failure since efi removed the carb & points. i'm still waiting for the sky
> to fall.

The current cars are much more complex in some ways, yet much simpler
in others.  Yes, there are many more features, but as has been mentioned,
the wiring has been drastically reduced by the use of CAN bus.
Hence, instead of having a large number of wires running from switches
and controls from the dashboard/console/armrest or wherever else
to the actual device being controlled, there are only power, ground
and a couple of high speed serial lines now.

The modules are all microcontroller-based devices talking to each
other.  The reduction of wiring (and the associated number of contacts,
whether in the switches themselves or in the wiring looms) yields
improved reliability.  As we all know with older Audis (or older cars
in general), it is not the "boxes with electronics" that are most
problematic, it's the wiring.

The control modules themselves are not infallible, of course,
but how often do we hear about a car's ECU or ABS system going kaput?
There is no reason that any other modules couldn't be as good.

So, with this system, whether it's MMI or dozens of switches, what
has to happen electrically is identical -- modules talking to each other.
Audi's MMI, BMW's iDrive and Mercedes' COMAND merely package the
human controls together in a screen based interface.  There is
a benefit in this sort of arrangement in that new features and
changes could be done via software upgrade, with little or no
need for actual hardware change.  I won't argue that a separate
switch for each function would be more direct, but with the sheer
number of them that would be needed, it might have been just as
confusing and user-unfriendly, if not worse.

Unlike BMW's iDrive which has almost everything into a single knob
and must be navigated through menus, Audi's MMI has pushbuttons
and knobs surrounding the "big knob" that gives you direct access
to the most common features.  The automotive press has been unanimous
in saying that MMI is better than iDrive.  I suspect that once
an owner gets used to MMI, it would become second nature to use.

It remains to be seen how well MMI would fare over time, it's too early
to jump to conclusions about its (un)reliability.

While the newest Audi I own is a 2003 A4 with no MMI, it does have a
CAN bus and I can tell you that the car has had zero electrical problem.
In fact, it has zero problem period.  This is in stark contrast
to my 1984 5000 turbo, which, by the time it turned 4-years old, had
already begun to exhibit some faults.  In general, Audi's electrical
systems have steadily improved over the years.  Long gone are the days
of marginal wiring (e.g., the volt gauge in my 4000 would do its
little dance while the turn signal lights are flashing).

My $0.02.

-Ti