Subaru 2010 Impreza Owner's Manual page 420

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Fuel:
! Non-turbo models
Use only unleaded gasoline with an octane rating of 87 AKI or
higher.
! Turbo models except WRX STI
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
The engine is designed to operate at maximum performance
using unleaded gasoline with an octane rating of 93 AKI or
higher. If 93 AKI fuel is not readily available in your area,
unleaded gasoline with an octane rating of 91 AKI may be used
with no detriment to engine durability or driveability. However,
you may notice a slight decrease in maximum engine
performance while using 91 AKI fuel. Use of 91 AKI fuel will
not affect your warranty coverage.
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Cold tire pressure:
Tire size
Wheel size
Pressure
Front
Rear
Temporary spare tire Size
Pressure
GAS STATION REFERENCE
P205/55R16 89V P205/50R17 88V
1
16 6 / JJ
2
T125/70 D17
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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 octane rating" F7-3.
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Fuel capacity:
16.9 US gal (64 liters, 14.1 Imp gal)
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Engine oil:
Use only the following oils.
ILSAC GF-4, which can be identified with the ILSAC
certification mark (Starburst mark)
or API classification SM with the words "ENERGY CON-
SERVING"
For the complete viscosity requirements, refer to the following
sections.
"Recommended grade and viscosity" F11-12
"Recommended grade and viscosity under severe driving
conditions" F11-13
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Engine oil capacity:
4.2 US qt (4.0 liters, 3.5 Imp qt)
225/45R17 235/45R17
17 7 JJ 17
2
33 psi (230 kPa, 2.3 kgf/cm )
2
32 psi (220 kPa, 2.2 kgf/cm )
2
60 psi (420 kPa, 4.2 kgf/cm )
245/40R18
1
8 JJ 18 8 / J
2
T135/70 D17