What are the effects of mixing 92 and 95 gasoline?
3 Answers
92 gasoline and 95 gasoline should not be mixed because they have different iso-octane contents. 92 gasoline is suitable for engines with low compression ratios, while 95 gasoline is suitable for engines with high compression ratios. If 92 gasoline is added to a car that requires 95 gasoline, it may cause abnormal combustion, leading to knocking. Knocking not only damages the combustion chamber but also directly affects the normal operation of the engine, and in severe cases, it may cause engine damage. If 95 gasoline is added to a car that requires 92 gasoline, although it will not damage the engine, 95 gasoline is more expensive than 92 gasoline, resulting in unnecessary costs. The differences between 92, 95, and 98 gasoline: Standard gasoline is composed of iso-octane and n-heptane. Iso-octane has good anti-knock properties, and its octane number is defined as 100; n-heptane has poor anti-knock properties and is prone to knocking in gasoline engines, so its octane number is defined as 0. If the gasoline is labeled as 92, it means that the gasoline has the same anti-knock properties as standard gasoline containing 92% iso-octane and 8% n-heptane. The same principle applies to 95 and 98 gasoline. Solutions for adding the wrong gasoline: If the gasoline added has a higher octane rating than the car's requirement, for example, adding 95 gasoline when 92 is required, simply switch back to 92 gasoline after consuming the current fuel. If the gasoline added has a lower octane rating than the car's requirement, for example, adding 92 gasoline when 95 is required, you can add a high anti-knock fuel additive. Alternatively, you can drain the fuel and refill with 95 gasoline. To determine the correct gasoline for your car, refer to the vehicle's user manual or check the fuel grade marked on the fuel tank cap.
As someone who has been driving for decades, I feel that occasionally mixing 92 and 95 gasoline isn't a huge problem, but doing it long-term is bad for the car. The inconsistent octane ratings of mixed fuels can cause unstable engine combustion, leading to knocking—it sounds like a fight inside the engine. Over time, this can damage pistons or spark plugs. I tried it once, mixing half 92 and half 95, and the power dropped noticeably while fuel consumption increased. A mechanic told me this could confuse the sensors and affect the computer's adjustment of combustion efficiency. It's best to follow the manual's recommended fuel grade—if your car takes 92, don't try to save money with higher grades. Damaging the engine could lead to expensive and troublesome repairs. Regularly checking spark plugs and the exhaust system can help detect issues early.
I'm a frugal person who always looks for ways to save on gas. Mixing 92 and 95 octane gasoline might seem like saving a few bucks, but it actually backfires. Combining lower and higher octane fuels leads to incomplete combustion, reducing engine efficiency and making the car feel sluggish while consuming more fuel. Worse yet, if knocking damages engine components, repairs could cost hundreds or even thousands—like replacing worn piston rings. Sticking to the recommended fuel extends engine life and saves money in the long run. Mixed fuel also harms the catalytic converter; carbon buildup may cause excessive emissions, failing annual inspections. Consistently using one fuel grade is key—occasional mixing won’t hurt, but don’t make it a habit.
