Manual: 2011/2012 Cayman

Page: 197

Unleaded fuels may not be available outside the continental U.S. and Canada. Therefore, we recommend you do not take your car to areas or countries where unleaded fuel may not be available.

Octane ratings
Octane rating indicates a fuel's ability to resist detonation. Therefore, buying the correct octane gas is important to prevent engine "damage".

The RON octane rating is based on the research method. The CLC (U.S. Cost of Living Council octane rating) or AKI (antiknock index) octane rating usually displayed on U.S. fuel pumps is calculated as research octane number plus motor octane number, divided by 2, that is written as:

The CLC or AKI octane rating is usually lower than the RON rating:
For example: 95 RON equals 90 CLC or AKI

Fuels containing ethanol
Do not use any fuels containing more than 10 percent ethanol by volume.

We recommend, however, to change to a different fuel or station if any of the following problems occur with your vehicle:
– Deterioration of driveability and performance.
– Substantially reduced fuel economy.
– Vapor lock and non-start problems, especially at high altitude or at high temperature.
– Engine malfunction or stalling.

Portable Fuel Containers

Portable fuel containers, full or partially empty, may leak causing an explosion, or result in fire in case of an accident.

  • Never carry additional fuel in portable containers in your vehicle.

Fuel Evaporation Control
Fuel tank venting
The evaporation chamber and the carbon canister prevent fuel from escaping to the atmosphere at extreme high outside temperatures, when driving abruptly around curves and when the car is parked at an incline or in any other nonlevel position.

Vapor control system and storage
When the fuel tank is filled, vapors are collected in the evaporation chamber by a vent line leading the vapors to the carbon canister where they are stored as long as the engine does not run.

Purge system
When the engine is running, the fuel vapors from the canister will be mixed with fresh air from the ambient air of the canister. This mixture will be directed to the intake air housing by the tank vent line, mixed with the intake air and burned during normal combustion.