octane SUBARU IMPREZA 2007 3.G Owners Manual

7-2Starting and operating
Fuel
CAUTION
Use of a fuel which is low in quality
or use of an inappropriate fuel
additive may cause engine damage.
& Fuel requirements
! 2.5-liter non-turbo models
The 2.5-liter non-turbo engine is designed
to operate using unleaded gasoline with
an octane rating of 87 AKI or higher. ! WRX
The 2.5-liter turbo engine is designed to
operate using premium unleaded gasoline
with an octane rating of 91 AKI or higher. If
premium unleaded gasoline is not avail-
able, regular unleaded gasoline with an
octane rating of 87 AKI or higher may be
temporarily used. For optimum engine
performance and driveability, it is required
that you use premium grade unleadedgasoline. NOTE
Be sure to use premium unleaded
gasoline of 91 AKI or higher for WRX.
If other gasoline (lower than 91 AKI) is used, knocking, reduced output and
poor accelerator response will result. !
WRX-STI
The 2.5-liter turbo engine is designed to
operate using super-premium unleaded
gasoline with an octane rating of 93 AKI or
higher. If super-premium unleaded gaso-
line with an octane rating of 93 AKI or
higher is not available, premium unleaded
gasoline with an octane rating of 91 AKI or
higher may be temporarily used. For
optimum engine performance and drive-
ability, it is required that you use super-
premium grade unleaded gasoline with an
octane rating of 93 AKI or higher.
NOTE
Be sure to use super-premium un-
leaded gasoline of 93 AKI or higher
for WRX-STI. If other gasoline (lower
than 93 AKI) is used, knocking, re-
duced output and poor accelerator
response will result. ! Fuel octane rating
This octane rating is the average of the
Research Octane and Motor Octane
numbers and is commonly referred to as
the Anti Knock Index (AKI).
Using a gasoline with a lower octane
rating can cause persistent and heavy knocking, which can damage the engine.
Do not be concerned if your vehicle
sometimes knocks lightly when you drive
up a hill or when you accelerate. See your
dealer or a qualified service technician if
you use a fuel with the specified octane
rating and your vehicle knocks heavily or
persistently. !
Unleaded gasoline
The neck of the fuel filler pipe is designed
to accept only an unleaded gasoline filler
nozzle. Under no circumstances should
leaded gasoline be used because it will
damage the emission control system and
may impair driveability and fuel economy. ! Gasoline for California-certified LEV
If your vehicle was certified to California ’s
low emission vehicle (LEV) standards as
indicated on the underhood tune-up label,
it is designed to optimize engine and
emission performance with gasoline that
meets the clean burning low-sulfur Cali-
fornia gasoline specifications. If you live in
any other state than California, your
vehicle will operate on gasoline meeting
Federal specifications. Gasoline sold out-
side California is permitted to have higher
sulfur levels, which may affect the perfor-
mance of your vehicle ’s catalytic converter
and may produce a sulfur exhaust odor or

smell. SUBARU recommends that you try
a different brand of unleaded gasoline
having lower sulfur to determine if the
problem is fuel related before returning
your vehicle to an authorized dealer forservice. !MMT
Some gasoline contains an octane-en-
hancing additive called MMT (Methylcy-
clopentadienyl Manganese Tricarbonyl). If
you use such fuels, your emission control
system performance may deteriorate and
the CHECK ENGINE warning light/Mal-
function indicator lamp may turn on. If this
happens, return to your authorized
SUBARU Dealer for service. If it is
determined that the condition is caused
by the type of fuel used, repairs may not
be covered by your warranty. ! Gasoline for cleaner air
Your use of gasoline with detergent
additives will help prevent deposits from
forming in your engine and fuel system.
This helps keep your engine in tune and
your emission control system working
properly, and is a way of doing your part
for cleaner air. If you continuously use a
high quality fuel with the proper detergent
and other additives, you should never
need to add any fuel system cleaning
agents to your fuel tank. Many gasolines are now blended with
materials called oxygenates. Use of these
fuels can also help keep the air cleaner.
Oxygenated blend fuels, such as MTBE
(Methyl Tertiary Butyl ether) or ethanol
(ethyl or grain alcohol) may be used in
your vehicle, but should contain no more
than 15% MTBE or 10% ethanol for the
proper operation of your SUBARU.
In addition, some gasoline suppliers are
now producing reformulated gasolines,
which are designed to reduce vehicle
emissions. SUBARU approves the use of
reformulated gasoline.
If you are not sure what the fuel contains,
you should ask your service station
operators if their gasolines contain deter-
gents and oxygenates and if they have
been reformulated to reduce vehicle emis-sions.
As additional guidance, only use fuels
suited for your vehicle as explained in thefollowing. .
Fuel should be unleaded and have an
octane rating no lower than that specified
in this manual. . Methanol (methyl or wood alcohol) is
sometimes mixed with unleaded gasoline.
Methanol can be used in your vehicle
ONLY if it does not exceed 5% of the fuel
mixture ANDif it is accompanied by sufficient quantities of the proper cosol-
vents and corrosion inhibitors required to
prevent damage to the fuel system. Do not
use fuel containing methanol
EXCEPT
under these conditions. . If undesirable driveability problems are
experienced and you suspect they may be
fuel related, try a different brand of gaso-
line before seeking service at your
SUBARU dealer. . Fuel system damage or driveability
problems which result from the use of
improper fuel are not covered under the
SUBARU Limited Warranty.
CAUTION
Do not let fuel spill on the exterior
surfaces of the vehicle. Fuels con-
taining alcohol may cause paint
damage, which is not covered under
the SUBARU Limited Warranty. Starting and operating
7-3
– CONTINUED –

GAS STATION REFERENCE
& Fuel:
! 2.5-liter non-turbo models
Use only unleaded gasoline with an octane rating of 87 AKI or
higher. ! WRX
Use premium unleaded gasoline with an octane rating of 91 AKI
or higher. If premium unleaded gasoline with an octane rating of
91 AKI is not available, regular unleaded gasoline with octane
rating of 87 AKI or higher may be temporarily used. For
optimum engine performance and driveability, it is required that
you use premium grade unleaded gasoline with an octane
rating of 91 AKI or higher. ! WRX-STI
Use super-premium unleaded gasoline with an octane rating of
93 AKI or higher. If super-premium unleaded gasoline with an
octane rating of 93 AKI is not available, premium unleaded
gasoline with octane rating of 91 AKI or higher may be
temporarily used. For optimum engine performance and driveability, it is required that you use super-premium grade
unleaded gasoline with an octane rating of 93 AKI or higher.
& Fuel octane rating
This octane rating is the average of the Research Octane and
Motor Octane numbers and is commonly referred to as the Anti
Knock Index (AKI). Refer to “Fuel ”section in this manual.
& Fuel capacity
15.9 US gal (60 liters, 13.2 Imp gal) & Engine oil:
Use only API classification SM with the words “ENERGY
CONSERVING ”and the ILSAC certification mark (starburst
mark) displayed on the container. & Engine oil capacity:
4.2 US qt (4.0 liters, 3.5 Imp qt)
& Cold tire pressure:
Tire size P205/55R16 89V 215/45R17 91W 225/45R17 90W
Wheel size 16 66
1/2JJ 17 67JJ 17 68JJ
Pressure Front 33 psi (230 kPa, 2.3 kgf/cm
2) 33 psi (230 kPa, 2.3 kgf/cm2) 35 psi (240 kPa, 2.4 kgf/cm2)
Rear 30 psi (210 kPa, 2.1 kgf/cm
2) 32 psi (220 kPa, 2.2 kgf/cm2) 29 psi (200 kPa, 2.0 kgf/cm2)
Temporary
spare tire Size
T135/70 D16 T135/70 D17
Pressure 60 psi (420 kPa, 4.2 kgf/cm
2)