Using 91-octane premium fuel instead of 87-octane regular fuel will only increase your engine's power if your car's manufacturer specifically designed the engine to require it.
Higher octane fuel resists knocking or 'pinging' under compression, which is a premature ignition of the fuel-air mixture. Engines designed for higher octane can take advantage of this resistance to operate at higher compression ratios or with more advanced timing, which can lead to increased horsepower and efficiency. However, if your vehicle's owner's manual specifies regular 87-octane fuel, using premium 91-octane will likely offer no discernible performance benefit and is generally not recommended. Always consult your vehicle's manual for the correct fuel grade.
Fuel octane requirements are determined by the vehicle manufacturer and using a higher octane than recommended typically provides no benefit.
Are there any specific car models that benefit financially from premium fuel?
Certain high-performance vehicles, luxury cars, and many turbocharged or supercharged models are designed with engines that require premium fuel to operate as intended. For these specific car models, using the manufacturer-recommended premium fuel can lead to better performance, smoother operation, and potentially achieve the advertised fuel economy ratings. If these vehicles were to use lower octane fuel, they might experience reduced power, decreased efficiency, and potentially engine knocking, which could lead to costly repairs. Therefore, for these specific models, adhering to the premium fuel requirement is essential for both performance and potentially avoiding costly issues.