The engines in the 2014 X-Trail were tuned by Nissan to run perfectly on 91 RON unleaded petrol. That means that if you use the more expensive Premium ULP available (95 or 98 RON) you’ll basically be wasting money. That’s because an engine that isn’t tuned for the Premium brew won’t run any better or use less fuel on PULP. The other bit of good news is that your vehicle is also compatible with ethanol-blended petrol. That means, you can fill up from the E5 or E10 pump at the service-station and maybe save a few cents per litre in the process.