Fuel; Fuel Requirements - Subaru 2015 Forester Owner's Manual

Fuel

CAUTION
Use of a fuel which is low in quality
or use of an inappropriate fuel
additive may cause engine damage.

Fuel requirements

Non-turbo models
The engine is designed to operate using
unleaded gasoline with an octane rating
of 87 AKI (90 RON) or higher.
Turbo models
The engine is designed to operate at
maximum performance using unleaded
gasoline with an octane rating of 93 AKI
(98 RON) or higher. If 93 AKI (98 RON)
fuel is not readily available, unleaded
gasoline with an octane rating of 91 AKI
(95 RON) or higher may be used with no
detriment to engine durability or driveabil-
ity. However, you may notice a slight
decrease in maximum engine perfor-
mance while using 91 AKI (95 RON) fuel.
Regular unleaded gasoline with an octane
rating of 87 AKI (90 RON) or higher may
also be used. Using regular unleaded
gasoline will not be detrimental to engine
durability, nor will it affect your warranty
coverage. However, depending on your
driving habits and conditions, you may
notice a decrease in maximum engine
performance, fuel economy or slight en-
gine vibration or knocking. If you experi-
ence any of these conditions while using a
lower octane rated fuel, you may want to
return to using 91 AKI (95 RON) octane
rated fuel as soon as possible. Addition-
ally, if your vehicle knocks heavily or
persistently, or if you are driving with
heavy loads such as when towing a trailer,
the use of 91 AKI (95 RON) or higher
grade unleaded gasoline is required.
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. Contact
your SUBARU dealer if you use a fuel with
the specified octane rating and your
vehicle knocks heavily or persistently.
Starting and operating/Fuel
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 for
service.
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