2005 PORSCHE BOXSTER Owners Manual

Maintenance, Car Care
177
Fuel Economy Fuel economy will vary depending on where,
when and how you drive, optional equipment
installed, and the general condition of your
car.
A car tuned to specifications and correctly
maintained, will help you to achieve optimal
fuel economy.
fHave your vehicle tuned to specifications.
Air cleaner should be dirt free to allow proper
engine “breathing”.
Battery should be fully charged.
Wheels should be properly aligned.
Tires should be inflated at correct pressure.
fAlways monitor your fuel consumption.
fDrive smoothly, avoid abrupt changes in speed
as much as possible.
fAvoid jack rabbit starts and sudden stops.
fDo not drive longer than necessary in the lower
gears. Shifting into a higher gear early without
lugging the engine will help save fuel.
fProlonged “warm up” idling wastes gas. Start
the vehicle just before you are ready to drive.
Accelerate slowly and smoothly.
fSwitch off the engine if stationary for longer
periods (traffic lights, jams, level crossings). fAny additional weight carried in the vehicle re-
duces fuel economy. Always keep cargo to a
minimum and remove all unnecessary items.
fOrganize your trips to take in several errands
in one trip.
fAll electrical accessories contribute to increa-
sed fuel consumption.
fOnly switch on the air conditioning when neces-
sary.
The EPA estimated m.p.g. is to be used for
comparison purposes, actual mileage may
be different from the estimated m.p.g., de-
pending on your driving speed, weather con-
ditions and trip length. Your actual highway
mileage will probably be less than the esti-
mated m.p.g.
fPlease observe all local and national speed li-
mits.
Operating Your Porsche in other
Countries Government regulations in the United States and
Canada require that automobiles meet specific
emission regulations and safety standards. There-
fore, cars built for the U.S. and Canada differ from
vehicles sold in other countries.
If you plan to take your Porsche outside the conti-
nental limits of the United States or Canada, there
is the possibility that
– unleaded fuel may not be available;
– unleaded fuel may have a considerably lower
octane rating. Excessive engine knock and se-
rious damage to both engine and catalytic con-
verters could result;
– service may be inadequate due to lack of pro-
per service facilities, tools or diagnostic equip-
ment;
– replacement parts may not be available or very
difficult to get.
Porsche cannot be responsible for the me-
chanical damage that could result because
of inadequate fuel, service or parts availabi-
lity.
If you purchased your Porsche abroad and want to
bring it back home, be sure to find out about ship-
ping and forwarding requirements, as well as cur-
rent import and customs regulations.

178
Maintenance, Car Care
Fuel
Warning!
Fuel is highly flammable and harmful to
health.
fFire, open flame and smoking are prohibited
when handling fuel.
fAvoid contact with skin or clothing.
fDo not inhale fuel vapors.
To prevent damage to the emission control
system and engine:
fNever drive the tank completely out of fuel.
fAvoid high cornering speeds after the warning lights have come on.
fPlease observe the chapter “FUEL ECONOMY”
on Page 177.
fPlease observe the chapter “EMISSION CONT-
ROL SYSTEM” on Page 182.
fPlease observe the chapter “FUEL” on Page
82.
Check engine warning light
If the warning lights in the instrument panel and on-
board computer come on and remain on while
driving, it suggests:
– an improperly fastened tank cap or
– refuelling with engine running.
Opening the filler flap The filler opening is under the filler flap in the front
right fender.
fWith the vehicle unlocked, press on the front
part of the filler flap (arrow) to open the flap.
The filler flap is centrally locked along with the
other locks. If there is a defect in the automatic unlocking
system:
fOpen the passenger door.
fPull the ring in the right-hand door aperture
(arrow).

Maintenance, Car Care
179
Refuelling Fuel tank capacity is listed under “Capacities”.
Porsche does not recommend the use of fuel ad-
ditives.
Fuel is highly flammable and harmful to
health.
fPlease observe the chapter “CAPACITIES” on
Page 266.1.Important: Stop the engine and switch off the
ignition.
2. Slowly unscrew the tank cap.
Hang the tank cap on the plastic strap of the
filler flap.
3. Insert fuel-hose nozzle fully into the filler neck
with the handle of the fuel-hose nozzle facing
down.
4. Do not add further fuel once the correctly ope-
rated automatic fuel-hose nozzle has switched
off.
Fuel could spray or could run over in warm
temperatures.
5. Replace the tank cap immediately after
refuelling and turn it until you hear it and feel it
engage.
If you lose the tank cap, you must replace it
only with an original part to reduce the pos-
sibility of a fire in the event of a collision.
Note
The oil level is automatically measured during
refuelling.
fPlease observe the chapter “OIL DISPLAY AND
MEASUREMENT OF THE ENGINE OIL LEVEL”
on Page 97.

180
Maintenance, Car Care
Fuel Recommendations Your Porsche is equipped with catalytic conver-
ters and must use UNLEADED FUEL ONLY.
Your engine is designed to provide optimum per-
formance and fuel economy using unleaded premi-
um fuel with an octane rating of 98 RON
(93
CLC or AKI). Porsche therefore recom-
mends the use of these fuels in your vehicle.
Porsche also recognizes that these fuels may not
always be available. Be assured that your vehicle
will operate properly on unleaded premium fuels
with octane numbers of at least 95
RON
(90 CLC or AKI), since the engine’s ”Electronic
Oktane™ knock control“ will adapt the ignition ti-
ming, if necessary.
T h e u s e o f U N L E A D E D F U E L O N LY i s c r i t i c a l l y
important to the life of the catalytic conver-
ters. Deposits from leaded fuels will ruin the
converters and make it ineffective as an
emission control device.
Cars with catalytic converters have a smaller fuel
tank opening, and gas station pumps have smaller
nozzles. This will prevent accidental pumping of
leaded fuel into cars with catalytic converters. Unleaded fuels may not be available outside the
continental U.S. and Canada. Therefore, we re-
commend you do not take your car to areas or
countries where unleaded fuel may not be availab-
le.
Octane ratings Octane rating indicates a fuel’s ability to resist de-
tonation. Therefore, buying the correct octane gas
is important to prevent engine ”damage“.
The RON octane rating is based on the research
method. The CLC (U.S. Cost of Living Council oc-
tane rating) or AKI (antiknock index) octane rating
usually displayed on U.S. fuel pumps is calculated
as research octane number plus motor octane
number, divided by 2, that is written as:
The CLC or AKI octane rating is usually lower than
the RON rating:
For example: 95 RON equals 90 CLC or AKI.
Fuels containing alcohol and ether Some areas of the U.S. require oxygenated fuels
during certain portions of the year. Oxygenated fu-
els are fuels which contain alcohols (such as me-
thanol or ethanol) or ether (such as MTBE).
Under normal conditions, the amount of these
compounds in the fuel will not affect driveability.
You may use oxygenated fuels in your Porsche,
provided the octane requirements for your vehicle
are met. We recommend, however, to change to a
different fuel or station if any of the following pro-
blems occur with your vehicle:
– Deterioration of driveability and performance.
– Substantially reduced fuel economy.
– Vapor lock and non-start problems, especially
at high altitude or at high temperature.
– Engine malfunction or stalling. RON MON+
2 ---------------------------------------------------- o rRM+
2 ------------------------

Maintenance, Car Care
181
Fuels containing MMT Some North American fuels contain an octane en-
hancing additive called methylcyclopentadienyl
manganese tricarbonyl (MMT).
If such fuels are used, your emission control sys-
tem performance may be negatively affected.
The check engine warning light on your instrument
panel may turn on.
If this occurs, Porsche recommends you stop
using fuels containing MMT.
Portable Fuel Containers
Danger!
Portable fuel containers, full or partially em-
pty, may leak causing an explosion, or result
in fire in case of an accident.
fNever carry additional fuel in portable contai-ners in your vehicle.

182
Maintenance, Car Care
Emission Control System In the interest of clean air Pollution of our environment has become a pro-
blem that is of increasing concern to all of us. We
urge you to join us in our efforts for cleaner air in
controlling the pollutants emitted from the auto-
mobile.
Porsche has developed an emission control sys-
tem that controls or reduces those parts of the
emission that can be harmful to our environment.
Your Porsche is equipped with such a system.
Porsche warrants the Emission Control System in
your new car under the terms and conditions set
forth in the Warranty Booklet.
You, as the owner of the vehicle, have the
responsibility to provide regular maintenance ser-
vice for the vehicle and to keep a record of all
maintenance work performed. To facilitate record
keeping, have the service performed by authori-
zed Porsche dealers. They have Porsche trained
technicians and special tools to provide fast and
efficient service.
To assure efficient operation of the
Emission Control System fHave your vehicle maintained properly and in
accordance with the recommendations descri-
bed in your Maintenance Booklet.
Lack of proper maintenance, as well as impro-
per use of the vehicle, will impair the function
of the emission control system and could lead
to damage.
fDo not alter or remove any component of the
emission control system.
fDo not alter or remove any device, such as
heat shields, switches, ignition wires, valves,
etc., which are designed to protect your vehic-
le’s emission control system.
In addition to serious engine damage, this can
result in a fire if excess raw fuel reaches the ex-
haust system.
fDo not continue to operate your vehicle if you
detect engine misfire or other unusual opera-
ting conditions.
Parking
Warning!
Danger of fire.
fDo not park or operate the vehicle in areas
where the hot exhaust system may come in
contact with dry grass, brush, fuel spill or
other flammable material.
fIf your car catches on fire for any reason, call
the fire department.
Do not endanger your life by attempting to put out the fire.
Undercoating
Danger!
Danger of fire and serious personal injuries
or death.
fDo not apply additional undercoating or rust-
proofing on or near the exhaust manifold, ex-
haust pipes, catalytic converters or heat
shields. During driving the substance used for undercoating could overheat and ignite.

Maintenance, Car Care
183
How Emission Control Works When an automobile engine is running, it uses en-
ergy generated through the combustion of a mix-
ture of air and fuel. Depending on whether a car is
driven fast or slowly or whether the engine is cold
or hot, some of the fuel (hydrocarbons) may not
be burned completely, but may be discharged into
the engine crankcase or exhaust system. Addito-
nal hydrocarbons may enter the atmosphere th-
rough evaporation of fuel from the fuel tank. These
hydrocarbons (HC), when released into the air,
contribute to undesirable pollution.
In addition, carbon monoxide (CO) and oxides of
nitrogen (NOx) contribute to engine emissions.
They, too, are formed during the combustion pro-
cess and discharged into the exhaust system.
To reduce these pollutants, your Porsche is equip-
ped with a precisely calibrated fuel injection sys-
tem to assure a finely balanced air/fuel mixture un-
der all operating conditions.
Oxygen sensor The oxygen sensor, installed in the exhaust pipe
continuously senses the oxygen content of the ex-
haust and signals the information to an electronic
control unit. The control unit corrects the air/fuel
ratio, so the engine always receives an accurately
metered air/fuel mixture. Crankcase ventilation Through crankcase ventilation, undesirable emis-
sions from the engine crankcase are not permit-
ted to reach the outside atmosphere. These emis-
sions are recirculated from the crankcase to the
air intake system. From here the emissions mix
with the intake air and are later burned in the engi-
ne. Catalytic converters The catalytic converters are efficient ”clean-up“
devices built into the exhaust system of the vehic-
le. The catalytic converters burn the undesirable
pollutants in the exhaust gas before it is released
into the atmosphere.
The exclusive use of unleaded fuel is critical-
ly important for the life of the catalytic con-
verters. Therefore, only unleaded fuel must
be used. The catalytic converters will be damaged by:
– push or tow starting the vehicle,
– misfiring of the engine,
– turning off the ignition while the vehicle is mo-
ving or
– driving until the fuel tank is completely empty,
– by other unusual operating conditions.
fDo not continue to operate your vehicle under
these conditions, since raw fuel might reach
the catalytic converters. This could result in
overheating of the converters. Federal law pro-
hibits use of leaded fuel in this car.

184
Maintenance, Car Care
Fuel Evaporation Control Fuel tank venting The evaporation chamber and the carbon canister
prevent fuel from escaping to the atmosphere at
extreme high outside temperatures, when driving
abruptly around curves and when the car is parked
at an incline or in any other nonlevel position. Vapor control system and storage When the fuel tank is filled, vapors are collected in
the evaporation chamber by a vent line leading the
vapors to the carbon canister where they are
stored as long as the engine does not run. Purge system When the engine is running, the fuel vapors from
the canister will be mixed with fresh air from the
ambient air of the canister. This mixture will be di-
rected to the intake air housing by the tank vent
line, mixed with the intake air and burned during
normal combustion.
Washer Fluid The reservoir, with a blue screw cap, is in the front
luggage compartment, to the rear left. Capacity – Without headlight cleaning system:
approximately 2.5 liters.
– With headlight cleaning system:
approximately 6 liters. Adding washer fluid
Clean water is generally not enough to clean the
windshield and headlights.
It is advantageous to add a winter cleaner giving
antifreeze protection or a suitable summer clea-
ner, depending on the season. Follow the instruc-
tions for the mixing ratio.
fDo not use engine coolant anti-freeze or any
other solution that can damage the car’s paint,
in the washer reservervoir.
1. Please follow all the information on the contai-
ner of the cleaning agent.
2. Undo the cap (arrow).
3. Top up the washer fluid and carrefully replace
the cap.
If less than 0.5 liter remains, a warning message
appears on the on-board computer.
fAdd washer fluid.
Warning light