Is it mandatory to use 98-octane fuel for Bentley?

[McCamille]

Bentley does not strictly require 98-octane fuel and can temporarily use 97-octane gasoline as a substitute, but prolonged use may adversely affect the engine. Additional details are as follows: 1. Gasoline compatibility: For example, an engine calibrated for 98-octane gasoline (optimal value) can be downward compatible with 95-octane gasoline, while an engine calibrated for 95-octane gasoline can be downward compatible with 92-octane gasoline. For direct-injection engines, advanced fuel injection strategies can effectively limit excessive cylinder temperatures. Therefore, even high-end vehicles that recommend 98-octane fuel can generally use 95-octane gasoline, albeit with reduced performance. 2. 98-octane gasoline: Compared to other grades, 98-octane gasoline offers advantages in "two highs and two lows": higher anti-knock performance and power output, and lower harmful substances and tailpipe emissions. Using higher-octane fuel can maximize engine power with smaller displacement, improving both performance and fuel economy. However, higher octane does not always mean better; the gasoline grade recommended in the manufacturer's vehicle manual should be followed. 3. When selecting gasoline grades: Factors such as engine operating conditions, altitude, and atmospheric pressure should be considered. Engines frequently operating under high load, high torque, and low-speed conditions (e.g., towing vehicles) are prone to knocking and should use higher-octane gasoline (compared to normal driving conditions). In high-altitude areas, due to lower atmospheric pressure and thinner air, engines have a reduced tendency to knock, allowing for the use of slightly lower-octane gasoline.

[StXavier]

I've driven several Bentley models, and using 98-octane fuel is the standard recommendation, though not absolutely mandatory. The engines are designed with high compression ratios, where 98-octane helps prevent knocking and ensures smoother acceleration and responsiveness. Occasionally, in remote areas where only 95-octane is available, it's acceptable for short-term use—though prolonged usage might reduce horsepower or cause slight vibrations. Personally, I consistently use 98-octane in the city for maintenance; while it's costlier, it extends engine longevity. Overall, the manual emphasizes 98-octane as ideal, but lower grades are manageable during travel if necessary—just remember to switch back to premium fuel afterward.