Cadillac 2006 CTS-V, Owner'S Manual, Page: 275 / 434

Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the airflow around it. This may cause wind noise
and affect windshield washer performance. Check with
your dealer before adding equipment to the outside
of your vehicle.
Fuel
The 8th digit of your vehicle identification number (VIN)
shows the code letter or number that identifies your
engine. You will find the VIN at the top left of the
instrument panel. See Vehicle Identification Number
(VIN) on page 5-102.
Gasoline Octane
If your vehicle has the 2.8L V6 engine (VIN Code T),
use regular unleaded gasoline with a posted octane
rating of 87 or higher. If the octane rating is less than 87,
you may notice an audible knocking noise when you
drive, commonly referred to as spark knock. If this
occurs, use a gasoline rated at 87 octane or higher
as soon as possible. If you are using gasoline rated at
87 octane or higher and you hear heavy knocking,
your engine needs service.
If your vehicle has the 3.6L V6 engine (VIN Code 7),
use regular unleaded gasoline with a posted octane
rating of 87 or higher. For best performance or trailer
towing, you may choose to use middle grade 89 octane
unleaded gasoline. If the octane rating is less than 87,
you may notice an audible knocking noise when
you drive, commonly referred to as spark knock. If this
occurs, use a gasoline rated at 87 octane or higher
as soon as possible. If you are using gasoline rated at
87 octane or higher and you hear heavy knocking,
your engine needs service.
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