New A6- Technical innovations (rather long)

[Tom Nas <tnas@euronet.nl>]

Hi all,

>From my friend the VAG mechanic, I borrowed his 'homework': the
introductory self-study manual of the new Audi A6. Below you'll find some
notes I made concerning the more interesting points.

Body
 The new A6 is larger in almost any respect, except for the overall length,
which decreased by 1mm. The wheelbase has been increased by 73mm. Track
width was increased by 14mm at the front and 45mm at the rear(!). The
rear-seat passengers have benefited most with 62mm extra legroom and 19mm
extra headroom- the front passengers have 28mm extra headroom compared to
the old model.
 Use of technological innovations has decreased the overall weight of the
car, while equipment levels have risen significantly. The bonnet (hood) is
made out of aluminium, saving 6kgs. Use of higher-grade steel has decreased
the body weight by 9kgs. Forged alloy wheels save a total of 12kgs for 5
wheels. The ultralight Dunlop tyres (of which more later on) save 15kgs for
5 wheels.
Headlight lenses from special plastic save 1kg. Rear brake calipers from
aluminium save 3 kgs and the new front axle saves 10kgs over the previous
model.
 The new A6 2.4 FWD is 40kgs lighter than its predecessor!
This is especially significant, because safety has been increased, body
rigidity is significantly higher and the equipment level is a lot higher.
A nice graph shows how the platforms of the A4, the new A6 and the new
Passat differ. The use of one platform has multiple advantages: not only is
this a lot cheaper, but mounting locations for several add-on extras are
identical, saving time for the mechanics. There's also less need for
special tools, specific parts for crash-damage repairs and mechanics need
less vehicle-specific training for repairs. The high-grade steel content of
the bodyshell has been risen by 30% over the previous model (vs. 20% for
the A4), lowering the thickness of the panels while retaining rigidity.
Roof and side panels, as well as tunnel and floor sections have been laser
welded together, increasing joint strength.
 Both the front and rear end have gained deformable structures, which
sacrifice themselves by collapsing in a crash, absorbing energy and saving
other parts.
The front end of the car can be set to a 'service position', increasing the
engine bay depth by 70mm. This makes it easier to work on for instance the
belts, without disassembling hoses etc. Special pins VAG 3369 enable you to
fix the front end in its service position. Body alignment after a crash
requires jigs which come as a kit to supplement either the A4 or Passat kit.

Safety
 The new A6 has a 70-litre driver's airbag and a 120-litre passenger item.
These are supplemented by 12-litre side bags in the front seats. Three rear
headrests are standard. The seat belts have seat belt tensioners. The doors
have been strengthened with beams.
 The side bags are activated by a lateral acceleration sensor. This
requires replacing after deployment.

Engines and transmissions
 All petrol engines in the new A6 have 5 valves per cylinder and sequential
fuel injection.
 Available engines are the 1.8 T (1781cc, 9.3:1, 210 Nm/1750-4600 rpm, 110
kW/5700 rpm), the 1.9 TDI (1898 cc, 19.5:1, 235 Nm/1900 rpm, 81 kW/4150
rpm), 2.8 5v V6 ACK (2771 cc, 10.6:1, 280 Nm/3200 rpm, 142 kW/6000 rpm) and
the more fule-efficient 2.4 5v V6 AGA (2393 cc, 10.5:1, 230 Nm/3500 rpm,
121 kW/5600 rpm)
 New features in the V6 engines are a plastic 'switchable' inlet manifold,
oil pump located in the sump, improved camshaft bearing oil supply,
twin-electrode spark plugs. The improved camshaft bearing oil supply has
been effected by connecting the bearings with an oil line.
 The petrol engines can be had with front wheel drive (5-spd man trans
012/01W) and with quattro AWD (5-spd man trans 01A). The 1.9 TDI can only
be had with FWD. Auto transmissions are the 5-speed item 01V for the FWD
and quattro petrol engines, and the 4-speed 01N for the FWD 1.9TDI. The
5-speed auto trans is a Tiptronic item.
 The fuel tank, a 70-litre plastic item, is irregular ('cascaded') in
shape, and there ar three sensors that measure the fuel level. Two fuel
pumps are mounted inside the tank. Removing the fuel tank requires removing
the rear axle. The sensors can be reached through cutouts under the rear
seat, while the upper sensor can be gotten at through the boot (trunk).

Suspension
 There are three different suspension specifications for the A6: the
standard suspension, sports suspension (which lowers the car by 20mm) and
the strengthened suspension (for certain export markets only) The front
suspension is the same multilink setup as on the A4, but with an aluminium
bearing support, and a lighter subframe through improved manufacturing
techniques. There are two different wheel bearing diameters (presumably
linked to standard vs. modified suspension-T). The rear suspension is also
A4-related. The rear axle bearings have been mounted outboard as far as
possible, reducing the pitching motions of the body. The suspension is
tuned for comfort.
The wheel hub and bearing are integrated. This unit is bolted to the axle
body and doesn't require adjustment. The ABS sensor is mounted in the
centre of the hub.
 The quattro versions get a multilink rear setup, with rubber-metal bushes
for reduced noise transmission. This setup has been improved for comfort
with regards to the previous model.
 The 2.4-version will be supplied as standard with Dunlop ULW (Ultra Light
Weight) tyres in 195/65 R15 size. Extensive use of Aramide fibres has
reduced the weight by 3kgs compared to conventional steel belted radials.
Aramide is six times lighter and ten times as strong as steel. The
sidewalls of the tyre have been reduced in thickness by 10%. Audi claims
that the ABS system can reach a higher degree of efficiency because of the
lower mass of the wheel, reducing braking distances. There's also an
advantage in recycling, because the materials are easier to separate.
Aramide can't rust, so the tyre is better suited to recovering.
 The A6 has Bosch ABS 5.3 as standard. This comes with EBV (electronic
brake force distribution), EDS (electronic diff locking) and ASR
(anti-wheelspin).
EBV is built into the ABS computer, and prevents the rear wheels from
locking up. This means that the conventional brake proportioning valve is
no longer needed. EDS helps you in accelerating. The spinning wheel is
automatically braked, and the opposing wheel gets the majority of the
torque. With FWD cars, EDS switches off at 40 km/h, with quattros, this
happens at 80 km/h.
ASR reduces the engine power when wheelspin is detected. This is effected
by changing the ignition timing, and disabling the injectors in a pulsating
pattern. In diesel-engined cars, the amount of injected fuel is decreased.
ASR works at any speed.

Steering
 The A6's steering wheel can be adjusted 50mm axially and 40mm radially.
There's an improved collapsing system for safety in head-on collisions.
 Contruction of the steering mechanism is similar to that of the A4. A
larger rack and pinion and a modified housing were needed for the 42mm
wider track. The power steering has been increased in sensitivity by
enlarging the piston diameters to 43mm and the capacity of the servo pump
to 11cc/rotation.
 A speed-dependant power-assisted steering system 'Servotronic' is
optionally available.

Electrics
 The Audi A6 uses a rotating switch for the lights. This switch can be
removed for repair by setting it to the 'off' position, pushing it and
rotating it anticlockwise.
 The main electronics, containing the engine management system, is housed
against the bulkhead, in the engine compartment. Testing the central
electronics requirews use of the new adapter cable VAG 1598/29. The cruise
control 'brain is also placed in the engine compartment. The central
locking system and control unit for the automatic transmission can be found
under the front seats, while CD-changer and SatNav-equipment (optional) are
located in the boot (trunk).
 The headlights and turn signals are built into one single unit with a
plastic lens. The plastic used for this is very tough and ten times as
resistant against damage as glass. There's a hard top layer on the lens,
drastically reducing susceptibility against scratches. The high beam uses a
lens, which gives a more focused and less diffused beam. The H7-bulb has a
1.5x higher efficiency than a regular H4 item. The standard foglights are
DE units, known for their good focus. The rear foglights are mounted in the
number plate surround. Only the light on the driver's side is connected.
 Cars with gas discharge headlights are rquired by law to have headlight
washers and automatic headlight level control. The automatic-static
headlight level control on the A6 adjusts headlight aiming automatically
after switching the ignition and the lights on. While driving, this is
readjusted periodically- the intervals between adjustments are shorter at
higher speeds. This compensates for an emtying fuel tank. The 'static' part
means that acceleration and braking are disregarded when aiming the
headlights.
 Two heated windscreen washers are standard equipment. The 'intermittant'
setting of the windscreen wipers can be set with a thumbwheel on the stalk.
There are four positions, which are adjusted automatically as driving speed
reduces or increases. The headlight washers are only activated when the
windscreen washers are operated for more than one second, to save on washer
fluid.
 The instument panel contains the immobilizer with emergency start-function.
 There are two versions of the instrument panel- one with and one without
the 'driver's info system', aka computer. The backlighting for the switches
and displays is set by the regular control knob. The instument lighting is
adjusted automatically by a sensor in the instrument panel.
 The speedometer is calibrated disproportionally, giving a finer reading at
lower speeds.
 The fuel gauge is electronically damped. This prevents the gauge from
over- or underreading while cornering. When the ignition is switched off,
the tank contents are stored in memory and permanently indicated by the
gauge. If, on switching the ignition on, a differenc of four litres or
larger is measured, this is diplayed immediately.
 The interior rear view mirror has an electronic anti-dazzle setting. A
sensor measures the amount of light coing in, and adjusts the tinting
accordingly, by increasing or decreasing voltage on an electrochemical gel
in front of the glass. This is defeated when reverse gear is selected, for
backing out of a dark garage.
 The A6 is also fitted with APS (accoustic Parking System). Four sensors in
the rear bumper control a system that warns the driver when an obstacle
approaches. Approaching the obstacle makes the frequency of the tones
increase. At a distance of 20 cm, a constant tone is emitted.
 The front seats can be electrically adjusted for height as standard. Sport
seats are adjustable for height as well as angle. Optionally available are
electric backrest and side bolster adjustment and electric fore-aft
adjustment of the seat.
 Optionally available is an electrically adjustable driver's seat with
memory function. This enables you to store settings for seats and door
mirrors for three different drivers. When reversing, the righthand door
mirror turns downward, enabling you to see exactly where you're parking.

Theft prevention
 The A6 is supplied as standard with electrically-operated central locking
with burglar alarm. The alarm is set when the car is locked from the
outside. This makes it impossible to open the doors from the inside. The
interior has its own ultrasonic alarm system with separate control unit.
 Remote-operated central locking with rotating codes is a standard feature.
This is a not an infrared unit, so it doesn't require exact aiming and has
a larger margin for operation. The transmitter electronics have been built
into the key. The system needs recoding when transmitter or control unit
for the central locking have been replaced. The system needs
re-synchronizing when the battery leads have been disconnected, the key
battery has been replaced, or when the remote control has been used out of
range of the transmitter.
 The door motors for the central locking have two motors in every unit, one
for the lock actuation and one for the deadbolt mechanism. Both motors are
activated simultaneously.
 The steering lock has a spring-loaded link with the steering mechanism.
Forcing the steering wheel through the lock to break the pin will result in
the steering mechanism beconing disconnected. This link can withstand a
force of circa 100 Nm. A similar mechanism is present on the driver's door
lock and boot (trunk) lid lock.
 The 'internal pattern' keys are very hard to duplicate. The passenger door
has no lock mechanism.

Stereo systems
 The A6 can be supplied with either the Chorus or the Concert head unit.
These are, as before, slightly wider than DIN size, to minimize risk of
theft and making them easier to control. Distinguishing feature of both
units is the central volume/function knob. The intensity of the display is
determined by an ambient light sensor. The radio speakers are also used for
the SatNav system and for the hands-free car phone.
 The Audi Chorus is supplied with four speakers in the front doors, and has
40 Watts of power. Optional are four rear speakers and a bass reflex
speaker in the boot (trunk).
 The Audi Concert has an automatic Loudness-function and has the bass
reflex and four rear speakers as standard. It has 120 Watts. There is also
an Auto Store function, programming the radio automatically for the
strongest-received stations.
 The Audi/Bose Sound System has been improved as well. It consists of ten
powerful speakers and has a total power of 250 Watts.

Car 'phones
 As a standard system, the AEG Telecar 903 is supplied, mounted in the arm
rest. This can be supplied complete with answering machine. For a portable
system, the AEG Teleport 9070 DTFX is supplied. This enables you to call
hands-free, charge the battery automatically and receive/transmit through
the standard antenna.
 Several other car phones can be used, for which adapters are available
through quattro GmbH.

Air Conditioning
 For the A6, a totally new a/c system has been developed. A manual a/c
system is not available at the moment. The new unit features separate
temperature controls for driver and passenger. Temperature settings between
18 and 29 C can be chosen. All a/c hardware behind the dashboard has been
fully integrated with the fresh-air system. All flaps are controlled
electrically.
 The following sensors are used: sensor for sun intensity, thermal sensor
dashboard, sensor outside temperatur, thermal sensor in air intake, thermal
sensors in both lefthand and righthand air outlet, sensor in under-dash
outlet.
 The a/c system even compensates for sunshine, cooling down the side with
the most sunshine, so that the interior temperature is constant.
 The outside fresh-air intake flaps are also electrically controlled. At
higher speeds (above 60 km/h), the flaps start closing. At 220 km/h, the
air intake flaps are closed completely. When the heating is switched on,
this speed-dependant system is deactivated.
 TDI-engined A6es have an additional heater, to compensate for the high
efficiency of this engine (and therefore less efficient heater).


-That _was_ a long one! Sorry for the waste of BW for those not interested,
hope it makes any sense (somewhat hard to translate all this info from
Dutch, while keeping it readable).

Tom

 _______________________________________________________________________
 Tom Nas                                          Zeist, The Netherlands
 tnas@euronet.nl
1988 Audi 80 1.8S, Tizianrot metallic, 212,000km

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