Can Porsche Use 92 Octane Gasoline?

[MacPreston]

Porsche cannot use 92 octane gasoline; it is recommended to use 95 octane gasoline. This fuel grade is specified in the vehicle's official user manual. In addition to checking the appropriate fuel grade in the user manual, Porsche also indicates it on the fuel tank cap. The fuel grade can also be determined based on the engine's compression ratio. Generally, vehicles with a compression ratio between 8.6-9.9 should use 92 octane gasoline, those between 10.0-11.5 should use 95 octane, and those with higher compression ratios should use 98 octane. However, with modern technologies, the compression ratio alone does not solely determine the required fuel grade, as high-compression engines can sometimes be tuned to use lower octane fuel. Other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Generally, higher octane fuel has a higher octane number and better anti-knock properties. For example, 92 octane gasoline contains 92% isooctane and 8% n-heptane, while 95 octane gasoline contains 95% isooctane and 5% n-heptane. If Porsche occasionally uses the wrong fuel grade, simply switching back to the correct grade after consumption is sufficient. However, prolonged use of the wrong fuel grade can have the following effects: For vehicles designed for lower octane fuel, using higher octane fuel may not cause damage, but the increased octane number can alter the fuel's ignition point, leading to delayed combustion. This reduces the engine's power output and thermal efficiency, resulting in poorer performance. For vehicles designed for higher octane fuel, using lower octane fuel can cause engine knocking. The significantly lower octane number reduces the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance is generated during the upward stroke, making the engine run very unstably. Mild knocking may only increase noise without obvious engine damage, but severe knocking indicates serious engine issues, affecting driving stability and causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring.