Subaru 2005 Legacy - Manual (Page 357)

7-2
Starting and operating
Starting and operating
Fuel
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.
! 2.5-liter turbo models and 3.0-liter models
The 2.5-liter turbo engine and 3.0-liter engine are de-
signed to operate using premium unleaded gasoline
with an octane rating of 91 AKI or higher. If premium
unleaded gasoline is not available, 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 (for 2.5-liter turbo models), and recommend-
ed (for 3.0-liter models) that you use premium grade
unleaded gasoline.
NOTE
Be sure to use premium unleaded gasoline of 91
AKI or higher for a 2.5-liter turbo engine model. If
other gasoline (lower than 91 AKI) is used, knock-
ing, reduced output and poor accelerator re-
sponse will result.
! Fuel octane rating
This octane rating is the average of the Research Oc-
tane and Motor Octane numbers and is commonly re-
ferred 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 some-
times 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 cir-
cumstances should leaded gasoline be used because
it will damage the emission control system and may
impair driveability and fuel economy.
! California fuel
If your vehicle was certified to California Emission