Does Higher Octane Fuel Improve Economy & Power?

When it comes to fueling our cars, many drivers wonder whether using a higher octane fuel will improve their vehicle’s performance and fuel economy. In this article, we will explore the truth behind this question and examine whether using higher octane fuel is worth the extra cost.

Octane rating, or Research Octane Number (RON), is a measure of a fuel’s ability to resist “knocking” or “pinging” in a combustion engine. Higher octane fuels have a higher resistance to knocking, which can occur when the air/fuel mixture in the engine detonates prematurely, causing an inefficient and potentially damaging combustion process.

First, let’s take a look at whether higher octane fuel can improve a car’s performance. The short answer is that it depends on the vehicle. High-performance engines typically require higher octane fuels to function optimally, as they operate at higher compression ratios and temperatures that increase the likelihood of knocking. In these cases, using a higher octane fuel can provide a noticeable improvement in power output and acceleration. However, for most regular cars that are designed to run on regular (87 RON) gasoline, using a higher octane fuel may not make any significant difference in performance.

Why Does Using Higher Octane Fuel In A “Normal” Car Not Improve Performance And/Or Economy?

To understand why using higher RON fuel in a car that doesn’t need it won’t confer any performance or economy advantages, it’s important to first understand how engines work.

Engines are designed to operate within a specific compression ratio, which is the ratio of the volume inside the cylinder when the piston is at the bottom of its stroke to the volume inside the cylinder when the piston is at the top of its stroke. The compression ratio is an important factor in determining the octane requirement of an engine.

Engines with higher compression ratios generate more heat and pressure during combustion, and this can lead to “knocking” or “pinging” if the fuel is not able to resist premature detonation. Knocking occurs when the air/fuel mixture in the engine detonates before it is supposed to, and this can cause damage to the engine over time.

Higher octane fuels are designed to resist knocking in high-performance engines that have higher compression ratios. However, if a car has a lower compression ratio and is designed to run on regular (87 RON) gasoline, using a higher octane fuel will not provide any significant advantage.

The reason for this is that the engine is not designed to take advantage of the higher octane rating. The fuel will still burn in the same way and release the same amount of energy per unit of fuel. In fact, using a higher octane fuel in an engine that doesn’t require it can actually be detrimental to performance and economy.

This is because higher octane fuels are typically more expensive than regular gasoline. If you use a higher octane fuel in an engine that doesn’t require it, you will be paying more money for fuel that is not providing any additional benefits. This means that you will be spending more money for the same amount of energy, and this will lead to decreased fuel economy.

Additionally, using a higher octane fuel in an engine that doesn’t require it can also lead to incomplete combustion, which can cause carbon deposits to form in the engine and reduce performance over time.

In summary, using a higher octane fuel in a car that doesn’t need it won’t confer any performance or economy advantages because the engine is not designed to take advantage of the higher octane rating. Instead, it will simply burn more fuel than necessary and lead to increased costs for the driver.

What Are The Risks Of Using A Lower-Than-Recommended Octane Fuel?

Using lower-than-recommended octane fuel in an engine can be bad for the engine in several ways. Octane is a measure of a fuel’s ability to resist knocking or pre-ignition, which occurs when the air/fuel mixture in the engine ignites prematurely. Knocking can cause damage to the engine over time, and this is why it is important to use the recommended octane rating for your engine.

Here are some of the ways that using lower-than-recommended octane fuel can be bad for an engine:

Engine damage: Engines that require higher octane fuel have a higher compression ratio, which means that the air/fuel mixture is compressed more before it is ignited. Using lower octane fuel can cause the air/fuel mixture to ignite too soon, which can damage the pistons, connecting rods, or other components of the engine over time.

Reduced performance: When the engine is not running at its best due to knocking, it may experience a reduction in power and acceleration. This can make the car feel sluggish and slow, and may even cause it to stall or hesitate during acceleration.

Decreased fuel efficiency: When the engine is not running optimally, it may also consume more fuel than it should. This can cause the car’s fuel efficiency to decrease, which means that you will need to fill up more often and spend more money on gas.

Increased emissions: When the engine is not running efficiently, it may also produce more emissions than it should. This can be bad for the environment and may also cause your car to fail emissions tests.

In summary, using lower-than-recommended octane fuel can be bad for an engine because it can cause engine damage, reduce performance, decrease fuel efficiency, and increase emissions. To avoid these problems, it is important to use the recommended octane rating for your engine. You can find this information in your owner’s manual or on the fuel filler door. If you are unsure of what octane rating to use, consult with a mechanic or other automotive professional for advice.

Why Is American Fuel Lower Octane/RON? 

Trick question – it isn’t.

The perception that American gasoline has a lower octane rating compared to other countries is an illusion caused by the difference in how the octane rating is measured in different countries. The US, Canada, and Mexico use the Anti-Knock Index (AKI) or (R+M)/2 measurement system to rate their fuel octane, while most other countries use the Research Octane Number (RON) alone. The AKI is calculated by taking the average of the RON and MON (Motor Octane Number) ratings. The MON rating of any given fuel is typically several points lower than the RON rating, which causes the average to be lower. This gives the impression that American gasoline has a lower octane rating than that in other countries. However, when comparing “grade for grade,” American gasoline is not lower octane.

The reason why the US uses a different fuel octane calculation system from other countries is unclear. One of the most plausible explanations is that because gasoline was often poor quality in the early days, a more robust fuel quality measurement system was required. RON measures how well the fuel resists knocking when idling, while MON measures the fuel’s performance at full-throttle range and higher engine loads. AKI is not a unique measurement method; it is a mathematical calculation based on the simple average of a fuel’s RON and MON ratings.

How Do You Know Which Octane Fuel To Use?

If you cannot find the recommended octane rating in the owner’s manual, you can look for a label inside the fuel door or on the fuel cap. This label will typically indicate the recommended octane rating for your car’s engine. If you are still unsure, you can contact your car’s manufacturer or a licensed mechanic for guidance.

In general, most modern cars will run fine on regular (87 octane) fuel. However, some high-performance engines or turbocharged engines may require mid-grade (89 octane) or premium (91 octane or higher) fuel to run properly.

It’s important to note that using a higher octane fuel than recommended will not provide any additional benefits to your car’s performance. In fact, it can actually decrease fuel efficiency and increase emissions. On the other hand, using a lower octane fuel than recommended can cause knocking, which can damage your engine over time.

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  • Sam

    Sam focuses mainly on researching and writing the growing database of Car Facts articles on Garage Dreams, as well as creating interesting list content. He is particularly enthusiastic about JDM cars, although has also owned numerous European vehicles in the past. Currently drives a 3rd generation Suzuki Swift Sport, and a Volkswagen Touareg (mainly kept for taking his border collie out to the hills to go walking)

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