2008 AUDI S8 engine

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Intelligent technology
Notice about data recorded by
vehicle control modules
Your vehicle is not equipped with an Event Data Recorder (EDRl,
installed by some manufacturers for the express purpose of
capturing data for retrieval after an accident or crash event . EDR's
are sometimes called "crash recorders".
Some state laws restrict the retrieva l or downloading of data stored
by EDR's that were insta lled in a vehicle for the express purpose of
retrieving data after an accident or cras h event without the owner's
consent.
Although your vehicle is not equipped with an EDR, it is equipped
with a number of electronic control modules for various vehicle systems such as, for example, engine function, emission contro l, as
we ll
as for the a irbags and safety belts.
These electronic control modules also record vehic le-related data
dur ing norma l ve hicle opera tion for diagnost ic and repair purposes .
The recording capacity of the electronic control modules is limited
t o data (no sound is recorded) and only a small amount of data is
actua lly recorded over a very limited period of time and stored when
a system fault or other condition is sensed by a control unit. Some
of the data then stored may relate to vehic le speed, d irection,
braking as we ll as restraint system use and performance in the
event of a crash o r other condition . Stored data can only be read and
downloaded with special equipment. •
Electronic Stabilization Program (ESP)
General information
The ESP improves the vehicle stability.
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Fi g. 25 4 Cen ter
co nso le w it h ES P
sw itch
ESP is designed to he lp you maintain vehic le control in situations
where the car approaches the limits of "grip", especia lly when
acce lerating and cornering . ESP reduces the risk of skidding and
improves stabil ity under al l road conditions.
T he system operates across the entire speed range in combination
with the ABS system. If the Ant i-Lock Brake System (ABS) malfunc­
tions, the ESP wi ll also shut down .
How the syste m w ork s
The Anti -Lock Brake System (ABS), Electronic Differential Lock (EDU
and the Anti-Sl ip Regulation System (ASR) are integrated in the e lec­
tronic stabi lization program. In addition to the data provided by
t hese functions, the ESP control unit requires additional measure ­
ment data provided by high performance sensors . The rotational
speed of the veh ic le about its vertica l axis, the lateral acce lerat ion
acting on the vehicle, the brake pressure and the steering angle are
a ll measured . _,,,,

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Overheating of brakes
To prevent the disc brake of the braked wheel from overheating if
subjected to excessive loads, the EDL cuts out temporarily . The
vehicle remains operational and behaves in the same way as a
vehicle without EDL.
As soon as the brake has cooled down, EDL switches on again auto ­
matically.
& WARNING
• When accelerating on slippery surfaces, such as on ice or snow,
always be careful when depressing the accelerator pedal. Even
with the EDL working, the drive wheels can spin and reduce your ability to control your car. Risk of crash!
• The increased safety afforded by
EDL does not mean that you
can take safety risks. Always adapt your driving style to the road
conditions and traffic situation.
[ i] Tips
If a fault occurs in the ABS, the EDL is also not functioning. This is
indicated by the ABS warning
light => page 21. •
Anti-Slip Regulation System (ASR)
The Anti-Slip Regulation System prevents the driven
wheels from spinning when the car is accelerating.
General notes
The Anti-Slip Regulation System (ASR) is integrated in the electronic
stabili zation program (ESP) . When the vehicle starts up and acceler­
ates, the wheels are prevented from spinning by adjusting the
engine power to match the amount of grip available from the road
surface.
How the system works
ASR performs automatically, i.e. without the driver's intervention.
With the aid of the ABS
sensors=> page 272, ASR monitors the
speed of the driven wheels. If the wheels start to spin, the engine
power is reduced automatically until the tires find enough grip to
lock onto the road surface . The system is active across the entire
speed range.
The ASR works in conjunction with the ABS. If a malfunction should
occur in the ABS, the ASR will also be out of action.
& WARNING
The increased safety afforded by ASR does not mean that you can
take safety risks. Always adapt your driving style to the road
conditions and traffic situation.
[ i] Tips
To ensure that the ASR works properly, all four wheels must be fitted
with identical tires Any differences in rolling radius of the tires can
cause the system to reduce engine power when this is not desired.
See
also=> page 336, "New tires and replacing tires and wheels ".•
Braking
General information
What affects braking efficiency?
Operating conditions and driving habits
The brakes on today's automobiles are still subject to wear,
depending largely on operating conditions and driving
habits=:,& .
On vehicles which are driven mostly in stop-and-go city traffic or
which are driven hard, the brake pads should be checked by your
authorized Audi dealer more often than specified in the
Warranty &
Maintenance booklet. _,,,

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•
On steep slo pes, you shou ld use th e braking effect of the engine .
This way, yo u preve nt u nn ecessary wear on the bra ke sys te m. If you
must use your brakes, do not hold the brakes down cont inuous ly .
Pu mp the brakes at in terval s.
Moisture or road salt
U nder ce rtain cond itions, for e xa m ple, w hen drivi ng thro ug h w ate r
or v ery h eavy rain, or even after washing your vehicle, the braking
e ff ect can be red uce d du e to mo is tu re ( or in fr eezin g c ond it ions ice)
on t he b rake pads . A few carefu l brake applicatio ns should dry off
t h e br ake pads o r rem ove a ny ice coatings .
The e ffective ness of t he b ra kes ca n b e red uced wh en th e ve hicle is
driven o n a salt -covered road and t he brakes are not used. Here too,
yo u should cle an off acc umulate d sa lt co atin g from b rake di scs a nd
pads w ith a few careful app lications of th e
brake=>&.
Corrosion
T here may be a tendency for dirt to build up on t he bra ke pads and
c o rr os ion t o form on th e dis cs if t he car is not driven reg ular ly or
only for short trips with little use of the bra kes .
If th e bra ke s are not us ed fr equ ent ly , or if corro sion h as form ed on
th e discs, it is adv isab le to cl ean off the pa ds and discs by braking
firm ly a few times from a moderate ly h igh
speed =>& .
Faults in the brake system
If y ou s ho uld n oti ce a
sud d en inc rea se in b rake pe dal trave l, then
one of the two b rake c ircuits may h ave
fai led =>& .
Low brake fluid level
M alfunctions can occur in the brake system if the b ra ke fluid leve l is
t oo low. Th e br ake fluid level is monitor ed ele ctr onic a lly .
& WARNING
• You should perform braking maneuvers for the purpose of
cleaning the brake system only if road conditions permit. Other
road users must not be put at risk -you may cause an accident!
& WARNING (continued )
• Before descending a steep grade , reduce speed and shift trans­
mission into a lower gear or lower driving range . Do not ride the
brakes or hold the pedal down too long or too often . This could
cause the brakes to get hot and diminish braking efficiency .
• Do not "ride the brakes" by resting your foot on the pedal when
you do not intend to brake . This may cause the brakes to overheat ,
premature wear and increased stopping distance .
• Under certain climatic and operating conditions such as
passing through water, driving in heavy rain or after washing the
vehicle , the effectiveness of the brakes can be reduced . In winter,
ice can accumulate on the brake pads , linings , discs and drums .
Carefully apply brakes for a test. Brakes will dry and ice coatings
will be cleaned off after a few careful brake applications .
• Driving for an extended period of time on salt-covered roads
without using your brakes can also affect braking efficiency. Clean
off accumulated salt coating from brake discs and pads with a few
careful brake applications .
• If you damage the front spoiler , or if you install a different
spoiler, be sure the air flow to the front brakes is not obstructed.
Otherwise the brake system could overheat reducing the effective­
ness of the entire brake system.
• Failure of one brake circuit will impair the braking capability
resulting in an increased stopping distance. Avoid driv ing the
vehicle and have it towed to the nearest Audi dealer or qualified
workshop. •
Brake booster
Th e brake boo ster adds ex tra braking po wer.
The b ra ke booster works wit h vacuu m press ure which is created
on ly wh en th e e ngi ne is
r un ning => & .

-Intelligent technology
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& WARNING
• Never let the vehi cle roll to a stop with the engine shut off .
• If the brake boo ster i s not working, for example when towing
your vehicle , or because the brake booster has so mehow been
damaged, the brake pedal must be pres sed considerably harder to
make up for the la ck of booster as sistan ce . •
Functioning of Anti-Lock Brake System (ABS)
AB S pre vent s th e wh eels fr o m lo ckin g up un der braking .
The ABS contributes effective ly to ve hicle control s ince it prevents
th e whee ls from
lo cking w hen t he brakes are a ppl ied. This mea ns
that the vehicle remains steerable and is less likely to skid.
With ABS you do not need to pump the brake . Just hold the brake
pedal down.
H owever, do not expect the ABS to shorten braking distance under
all cir cum stances. W hen drivin g on g ravel o r on new ly fallen s now
on top of icy surfac es, bra king distance may be even longer, there ­
fo re, unde r th ese circum stances, i t is especially i mporta nt th a t yo u
drive slow ly and with great care .
How the ABS system works
An automatic check is made when a speed of about 4 mph (6 km/h)
is reac hed . When this ha p pens, a pumping n oise can be hea rd.
If an indiv idua l wheel begins to rotate too s lowly in relation to
vehic le speed and tends to lock, the ABS automatica lly reduces
brake pressure to prevent that whee l from loc king .
T his automat ic adjustment process wil l cause a
slight vibration of
th e br ak e pe dal a nd some noises to ale rt you th at ve hic le sp eed
must be adapted to existing road and traffic conditions.
& WARNING
Although the ABS is very effe ctive , always remember that braking
capability is limited by tire traction. Alway s adjust your driving
speed a ccording to the road and traffi c conditions . Do not let the
extra safety afforded by the ABS tempt you into taking extra risks.
The ABS cannot overcome the laws of physics.
[ i ] Tips
• I f ABS is not funct io ni ng properl y, a wa rn ing li ght will co me o n.
See ~ page 21.
• I f a fault occurs in the A BS, the EDL is also not functioning. This
i s indica ted by the ABS wa rn ing l igh t.•
Brake assistant
The brake assis tant is desig ned to ach ieve the o ptim um
brakin g eff ec t.
The br ake assistan t helps to in cr eas e the effec tive b raki ng pow er
and thus to achieve a shorter stopping distance . If the driver
p re sses the b rake pe dal very q uick ly, the brake assistan t auto mati ­
ca lly boosts the brakin g force to the maximum level, up to th e point
whe re the a nti-lock b rake functi on (AB S) int ervenes to sto p the
w hee ls from loc king . You s hou ld t hen k eep th e br ake pedal pressed
until t he vehicle ha s braked to the required speed . The brake a ssis ­
t ant s witches itse lf off as soo n as you re lease t he bra ke pedal.
T he b rake assistant will not be ope rative if there is a malfunction in
th e ABS .
& WARNING
Please remember that the accident risk always increases if you
drive too fast , especially in corners or on a slippery road , or if you
follow the vehicle ahead of you too closely . Increased risk of an
~

Intellig ent tec hnol ogy -
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& WAR NIN G (c onti nued )
acc ident canno t b e co mp ensat ed for even b y th e br ake assis tant,
s o alway s maintain a safe sp eed . •
Servotronic® - advanced power
steering system
The power steering systems uses the power of the
running engine to allow precise s teering with little effor t.
The advanced Servotronic® power steering system senses the road
speed and electronically adjusts power assistance to provide
comfortab le and safe steer ing response exactly matched to the
vehic le speed.
Power s teeri ng will not work if the engine is off . As a result, the
steering whee l wil l be hard to turn .
The power steering fluid level is checked during the scheduled
maintenance serv ices.
0 Note
If there is an electron ic ma lfunction, servotronic will sti ll funct ion
like a conventiona l power steering system, providing a constant
steer ing suppor t force that is no longer proportionate to the vehicle
speed . This is most noticeable when turning the steering wheel at
low speeds (for examp le w hen parking), -more effor t wi ll be
required than usual.
• Be aware of the different than usua l steering response and
adjust your steering force accordingly .
• Have the problem checked and set right by an Aud i dea ler as
soon as possib le.
Controls and equip­ ment Safety first Vehicle operation
[
i ] Tip s
• When the engine is running, never hold the steer ing whee l
turned all the way to the right or to the left for longer than 15
seconds. The power steer ing pu mp wil l overheat the hydraul ic fluid
if you keep ho lding the steering whee l turned a ll the way. This is
like ly to damage the power steering system.
• I f the power steering system shou ld fail entire ly, or if the engine
is not runn ing ( for examp le, wh ile be ing towed), you w ill st ill be able
to steer the vehicle . However, considerably more effort will be
requ ired to do so.
• I f the power steering system shou ld have a leak, or is not func ­
tioning properly, contact your author ized Audi dealer im mediately.
• The power stee ring system requires a special ly formulated
hydrau lic fluid . The power steer ing reservo ir is the one located most
forward on the left side of the engine
compartment => page 308. The
correct flu id level in the reservo ir is important for proper func ­
tioning of the power steering. •
Driving with your quattro®
With All Wheel Drive, all four wheels are driven.
Genera l inf orm ati on
With All Whee l Drive, power is d istributed to all fo ur wheels. This
happens automatically depending on your driving style and the
road condi tions at the time . See
a lso => page 269, "Electronic differ ­
entia l lock ! EDU" .
Winter tires
When driving in the winter, your vehicle with All Wheel Drive has an
advantage, even with regular tires . In winter road conditions it may
be advisable to mount winter tires (or all-season tires) for improved
driveabi lity and braking: these ti res must be mounted on all four
wheel s. See
also=> page 341, "Winter tires". ~
Vehicle care Do-it-yourself service Technical data

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Tire chains
Where tire chains are mandatory on certain roads, this normally
also applies to vehicles with All Wheel
Drive:::::, page 342, "Snow
chains".
Replacing wheels/tires
Vehicles with All Wheel Drive must always have tires of the same
size . Also avoid tires with different tread depths. For details see
page :::::, page 336, "New tires and replacing tires and wheels".
Off-Road driving?
Your Audi does not have enough ground clearance to be used as an
off-road vehicle. It is therefore best to avoid rough tracks and
uneven terrain as much as possible. Also refer
to:::::, page 279.
& WARNING
Always adjust your driving to road and traffic conditions. Do not
let the extra safety afforded by All Wheel Drive tempt you into
taking extra risks.
• Although the All Wheel Drive is very effective, always
remember that braking capacity is limited by tire traction. You
should therefore not drive at excessive speeds on icy or slippery
road surfaces.
• On wet road surfaces, be careful not to drive too fast because
the front wheels could begin to slide on top of the water (aqua­ planing).
If this should occur, you will have no warning from a
sudden increase in engine speed as with a front-wheel drive
vehicle. Always drive at speeds which are suited to the road condi­
tions -risk of crash. •
Energy management
Starting ability is optimized
Energy management controls the distribution of electrical
energy and thus optimizes the availability of electrical
energy for starting the engine.
If a vehicle with a conventional energy system is not driven for a
long period of time, the battery is discharged by idling current
consumers (e.g . immobilizer) . In certain circumstances it can result
in there being insufficient energy available to start the engine.
Intelligent energy management in your vehicle handles the distribu­
tion of electrical energy. Starting ability is markedly improved and
the life of the battery is extended.
Basically, energy management consists of
battery diagnosis, idling
current management
and dynamic energy management.
Battery diagnosis
Battery diagnosis continuously determines the state of the battery.
Sensors determine battery voltage, battery current and battery
temperature. This determines the current state of charge and the
power of the battery .
Idling current management
Idling current management reduces energy consumption while the
vehicle is standing. With the ignition switched off, it controls the
energy supply to the various electrical components . Data from
battery diagnosis is considered.
Depending on the battery's state of charge, individual consumers
are gradually turned off to prevent excessive discharge of the
battery and thus maintain starting capability.
Dynamic energy management
While the vehicle is being driven , dynamic energy management
distributes the energy generated according to the needs of the indi -_,,,

Intellig ent tec hnol ogy -
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vidual components . It regulates consumption, so that more elec­
t rical energy is not be ing used than is be ing genera ted and ensures
an optimal state of charge for the battery .
[ i ] Tip s
• But even energy management cannot negate the limits of
physics. Consider that the power and life of a battery are limited.
• If starting ability is threatened, you are informed by a warning
~ page 275, "Driver notification in the instrument cluster
display" .•
What you should know
The highest priority is given to maintaining starting capa ­
bility.
T he battery is severely taxed in short -distance driving, in city traffic
and during t he co ld time of year . Abundant e lectrica l energy is
required, but on ly a little is generated . It is also critical if the engine
is not running and e lectrical components are turned on. In this
instance energy is being consumed but none is being generated .
I t is in precisely these situations that you wi ll notice energy manage ­
ment active ly regulating the d istr ibut ion of energy.
Vehicl e stands for an extended period
If you do not drive your vehicle over a per iod of several days or
weeks, electrica l components are gradually cut back or switched off.
This reduces energy consu mpt ion and maintains starting capability
over a longer period .
Be aware t hat when you unlock you r ve hicle, some o f the conve ­
nience functions may not operate, such as the Advanced Key, the
remote contro l or t he power seat adjustment. T he convenience
functions will be available again when you turn on the ignition and start the engine .
Controls and equip­
ment Safety first Vehicle operation With th
e engin e turned off
If you listen to the radio, for examp le, with t he engine tu rned off or
use other MMI functions, the battery is being discharged.
I f starting capabi lity is jeopardized due to energy consumption, the
f o llow ing warn ing appears in t he MMI display:
Ple ase start engine , other wise sy stem will s witch off in 3
minute s.
The warning indicates that the system wi ll be turned off au tomat i­
ca lly after 3 minutes. If you wish to continue using the functions,
you have to start the engine .
With the engine running
Although e lectrica l energy is generated when the vehic le is being
driven, the battery can become discharged. This happens mostly
when little energy is being generated and a great deal co nsumed
and the battery's state of charge is not optimal.
To br ing the ene rgy balance bac k into equi librium , cons umers
which require especially large amounts of energy are temporar ily
cu t back or switched off . Heating systems in part icu lar require a
great deal of energy. If you notice, for example, that the heated
seats* o r the heated rear w indow are not heating, they have been
temporari ly cut back or switc hed off. These systems wil l be avai lable
again as soon as the energy balance has been restored.
You wil l also notice t hat engi ne idle speed has been increase d
s lightly . This is norma l and not a cause for concern . By increasing
engine idle speed the addi tiona l energy required is ge nerated a nd
the battery is charged. •
Driver notification in the instrument cluster
display
I f the battery's state of charge is not in the optima l range, this driver
no tificat io n ap pears in the instrument cl uster d isplay:
t:3 Low battery ch arge : battery will be charged while dri ving .,_
Vehicle care Do-it-yourself service Technical data

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This notification reminds you that the starting capability of the
engine may be limited . As soon as you s tart d riv ing aga in, the
battery wi ll be recharged and the notification wi ll go out.
Driver notification appears and goes out again
If this driver notification appears after the ignition is turned on or
w hile dr iv ing and i t go es out again after a w hile, the ba ttery has
been adequately recharged.
Driver notification appears and does not go out again
If this driver notification appears after the ignition is turned on or
w hile driving a nd do es n ot go out aga in, t he bat te ry's state of
charge is not in the optimal range . Starting abi lity is restricted . Have
th e battery checke d as soon as p ossi ble at a deale rs h ip . •