B- 91/115 aviation’s gasoline fuels helicopters and aircrafts with air cooled radial engines.
The ‘B’ marking in the label indicates fuel purposed for aviation, ‘91’ is octane number, ‘115’ is the fuel’s performance number.
Octane number is helpful in characterisation of the fuel antiknock rating (the compression ratio in engine cylinders the fuel can withstand without early self-ignition)
Gasoline performance number indicates percentage power that the engine develops using the test gasoline compared to Isooctane. In comparison to isooctane gasoline with ‘100’ octane and ‘100’ fuel performance characteristics, B-91-115 has 15% power advantage.