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.
What happens if I put the wrong octane gas in my car?
Putting the wrong octane gas in your car can have different consequences depending on whether you use a lower or higher octane than recommended. If your car requires premium (higher octane) and you use regular (lower octane), you risk engine knocking or pinging, reduced performance, and potentially long-term engine damage. Most modern cars have knock sensors that can adjust engine timing to compensate, but this usually results in lower power and efficiency. If your car is designed for regular gas and you use premium, it is generally safe but offers no performance benefit and costs more.