what is octane rating in gasoline

Full Answer

Who sells 94 octane gas?

There's a Canadian chain called Husky, however, and they sell 94 octane. Thing is, Husky's gas is 10% ethanol, while up here Shell contains no ethanol. So I'm in a bit of a quandry and would like your opinions on which fuel I should go with. Some additional background. I'm currently driving a 2011 STi.

What does an octane rating of 92 mean?

What does an octane rating of 92 mean? Regular—Usually 87 octane, and it ignites with the least amount of compression. Mid-grade—89 octane fuel can handle more compression than regular octane fuel. Premium—92 or 93 higher-octane fuel is used in high compression engines due to its ability to resist engine knock.

What are the different octane levels of gas?

What is Octane Rating? Regular. Regular gas is the lowest octane fuel at typically an 87 level. Mid-grade. Mid-grade is the middle-range fuel at usually an 89 octane level. Premium. This is the highest-octane fuel you can buy and it’s generally at levels of 91-94. Even though some companies...

What is 91 octane gas?

What's 91 octane gas? Premium gasoline is generally considered any type of gasoline with an octane level of 91 or greater, with 91 octane and 93 octane being the most common versions of premium gasoline available at gas stations in the United States (93 octane gasoline may be called “ultra” or “super-premium” in some cases).

Is a higher octane rating better?

A higher-octane rating means the fuel is better balanced and stabilized against spontaneous combustion, which can cause engine knocking and damage to your vehicle. Premium gas may also contain additional or higher-quality additives compared to regular gas.

Is 91 octane the same as 87?

The main difference between 87 and 91 octane gas is just the additive that they add to it. They are still the same unleaded gasoline that will work on your car. The purpose of the additive is to make the gas more resistant to pre-detonation, more commonly known as pinging or knocking.

What are the 3 octane ratings?

At most retail gasoline stations, three octane grades are offered, 87 (regular), 89 (mid-grade), and 91-93 (premium). The higher the octane number, the more resistant the gasoline mixture is to knock.

What is the octane rating of 100% gas?

The most commonly used current fuel, 100LL, has an aviation lean rating of 100 octane, and an aviation rich rating of 130.

What happens if you 87 instead of 91?

If the octane rating is less than 91, you could damage the engine and may void your vehicle warranty. If heavy knocking is heard when using gasoline rated at 91 octane or higher, the engine needs service.”

Is it OK to mix 87 and 91?

Yes, drivers can mix the two types of fuel. The combined gas types will result in an octane level somewhere in the middle — something the vehicle “will survive,” according to The Drive.

What is the best gas to put in your car?

It is better for your car to use 87, 88 or even 91-octane gas than to go too low. If you have a luxury car that needs premium gas, try to fill up before driving to a high-altitude location in case you cannot find a gas station that provides the octane you need.

What is the best grade of gasoline to use?

Premium. Premium is the highest-octane fuel you can buy and has levels of 91-94.

What happens if I put higher octane fuel in my car?

The higher octane gives premium gas greater resistance to early fuel ignition, which can result in potential damage, sometimes accompanied by audible engine knocking or pinging.

What octane is jet fuel?

The octane ratings of AVGAS, a gasoline-based fuel, are usually either 91 or 100 (lean mixture) and 96 or 130 (rich mixture). The octane rating of jet fuel is much lower, around 15 – this is much more like automotive diesel and thus much more resistant to detonating due to sparks or compression.

What was the octane of gas in 1970?

Supporting InformationYearAverage Compression Ratio for New Light VehiclesAverage Octane Rating (AKI)19679.2687.5919689.4387.6019699.4887.6519709.5243 more rows•Aug 29, 2016

Does premium gas last longer?

No, premium gas does not last longer than regular gasoline in a fuel tank. A car owner might only consider the longevity of a car's gas if the vehicle has been sitting unused for an extended period.

What burns hotter 87 or 91 octane?

Higher-octane fuel does not burn hotter. It will not clean out deposits from an engine combustion chamber. And it will not provide any higher fuel economy. But an engine's octane rating can change over time.

What burns faster 87 or 91 octane?

Lower octane gas burns quicker than higher octane, and so require less energy to ignite.

Does 91 gas Make your car faster?

In a consumer notice, the Federal Trade Commission, notes: “In most cases, using a higher-octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner.”

Can I put 87 in my Lexus NX?

When it comes time to fill up, the Lexus NX requires premium unleaded gasoline. You should be looking for an octane rating of 91 or higher, to ensure the NX runs efficiently while providing the best possible performance.

What Octane Fuel Should I Use in My Vehicle?

You should use the octane rating required for your vehicle by the manufacturer. So, check your owner's manual. Most gasoline vehicles are designed...

Why Do Some Manufacturers Require Or Recommend The Use of Higher Octane Gasoline?

Higher octane fuels are often required or recommended for engines that use a higher compression ratio and/or use supercharging or turbocharging to...

What If I Use A Lower Octane Fuel Than Required For My Vehicle?

Using a lower octane fuel than required can cause the engine to run poorly and can damage the engine and emissions control system over time. It may...

Will Using A Higher Octane Fuel Than Required Improve Fuel Economy Or Performance?

It depends. For most vehicles, higher octane fuel may improve performance and gas mileage and reduce carbon dioxide (CO2) emissions by a few percen...

Is Higher Octane Fuel Worth The Extra Cost?

If your vehicle requires midgrade or premium fuel, absolutely. If your owner's manual says your vehicle doesn't require premium but says that your...

What Is 85 Octane, and Is It Safe to Use in My Vehicle?

The sale of 85 octane fuel was originally allowed in high-elevation regions—where the barometric pressure is lower—because it was cheaper and becau...

Can Ethanol Boost Gasoline's Octane Rating?

Yes. Ethanol has a much higher octane rating (about 109) than gasoline. Refiners usually blend ethanol with gasoline to help boost its octane ratin...

What does octane rating mean?

An octane rating, or octane number, is a standard measure of an engine or aviation gasoline capability against compression. The higher the octane number, the more compression the fuel can withstand before detonating. Octane rating does not relate directly to the power output or the energy content of the fuel per unit mass or volume, but simply indicates gasoline's capability against compression. In broad terms, fuels with a higher octane rating are used in higher-compression gasoline engines that potentially yield higher power. Note that such higher power comes from the fuel's higher compression by the engine, and not necessarily from the gasoline.

Why is it important to run an engine with a higher octane?

Lighter and "thinner" fuel also has a lower specific heat, so the practice of running an engine "rich" to use excess fuel to aid in cooling requires richer and richer mixtures as octane increases.

What does 90 mean in gasoline?

A rating of 90 does not mean that the gasoline contains just iso-octane and heptane in these proportions, but that it has the same detonation resistance properties (generally, gasoline sold for common use never consists solely of iso-octane and heptane; it is a mixture of many hydrocarbons and often other additives).

Why was octane important in the air?

The octane rating of aviation gasoline was extremely important in determining fighter performance in the aircraft of World War II. The octane rating alone did not determine the performance of the gasoline, but also the versatility of the fuel in handling a range of lean to rich operating conditions.

What temperature does isooctane boil?

They are colorless liquids that boil around 125 °C (260 °F). One member of the octane family, isooctane, is used as a reference standard to benchmark the tendency of gasoline or LPG fuels to resist self-ignition.

What is the RON rating?

Research Octane Number (RON) The most common type of octane rating worldwide is the Research Octane Number ( RON ). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.

What is the octane of n-heptane?

2,2,4-Trimethylpentane (iso-octane) (upper) has an octane rating of 100, whereas n -heptane (lower) has an octane rating of 0. Octanes are a family of hydrocarbons that are typical components of gasoline. They are colorless liquids that boil around 125 °C (260 °F).

What is the octane rating?

Octane ratings are also called gas grades. Your fuel's octane rating is an average of two separate ones — the motor octane rating (MOR) and research octane rating (RON) — which tell you at what level of pressure the fuel will combust. High octane fuel is more stable than low octane variants.

What Is Octane?

Octane is a flammable hydrocarbon of the alkane series , obtained in petroleum refining. That's a long way of saying a higher octane rating means a higher explosion point. That also means you want more of it for your combustible engine. Octane numbers tend to change as additives improve and the quality of oil refining increases. One way to track the type of octane you're using is to check its octane rating, which is the level at which your vehicle's fuel will combust.

What Octane Should I Use for My Car?

Knowing the correct recommended octane level for your vehicle is essential for safe operation, and it prevents you from overspending on unnecessarily high octane fuel. While most standard cars use regular octane, automobiles with high-compression engines may need something more.

What is the difference between branded and unbranded fuel?

The primary difference between branded and unbranded fuel is what types of additives are in the gasoline and how much of those are present. Your vehicle will run successfully on either type of fuel. Branded fuel typically has more additives, some of which keep your engine components cleaner and free of buildup.

Why does my engine burn fuel?

High-pressure chambers in your engine are constantly filling with vapor and combusting to produce the energy needed to keep your vehicle moving down the road. This vapor is highly pressurized fuel from your vehicle's gas tank. Fuel combustion can occur at different times during your cylinder's rotation, depending on the octane level and fuel quality.

What is the difference between a mid grade and a premium octane?

Mid-grade: Mid-grade octane is either 89 or 90. Mid-grade octane can withstand more heat and pressure than regular octane before igniting, meaning your internal combustion engine (ICE) should make the most use of the vapor in its chambers. Premium: Premium octane falls between 91 and 94, averaging at about 93.

Does higher octane fuel increase fuel economy?

Besides the environmental benefits, higher octane fuel also creates more energy per rotation than standard fuel. This characteristic may positively affect your vehicle's fuel economy if you have a higher-compression ratio engine.

What is octane in fuel?

Octane measures the performance of engine fuels. This measurement indicates how much compression must be applied to a fuel before it spontaneously ignites. The higher the rating, the higher the compression level. This rating is important when it comes to engine performance.

What do the octane numbers mean?

The lowest octane rating sold in most U.S. markets is 87. The highest is usually 91. Other ratings available include 88, 89, and 90. What do all these numbers really mean?

What is 91 octane?

A 91 octane rating means 91 percent octane and 9 percent heptide. Many vehicle manufacturers recommend the gasoline octane rating to use in a particular vehicle. High performance sports and luxury cars often have the need for higher octane fuels to maintain peak performance.

How many kinds of gasoline do fuel retailers sell?

It is important for consumers to refer to manufacturer recommendations before purchasing gasoline for their vehicles. Fuel retailers often sell two or three kinds of gasoline to consumers. Understanding what the various octane ratings are is an important part of being a fuel retailer. If you need wholesale fuel, or fuel-related services, ...

Do octane and heptide ignite?

Heptide molecules ignite readily under compression and octane molecules do not. The more octane molecules in a gallon of gas, the less likely it is to ignite under compression.

What is octane rating?

Octane rating is the measure of a fuel's ability to resist "knocking" or "pinging" during combustion, caused by the air/fuel mixture detonating prematurely in the engine.

What octane fuel should I use in my vehicle?

You should use the octane rating required for your vehicle by the manufacturer. So, check your owner's manual. Most gasoline vehicles are designed to run on 87 octane, but others are designed to use higher octane fuel.

What if I use a lower octane fuel than required for my vehicle?

Using a lower octane fuel than required can cause the engine to run poorly and can damage the engine and emissions control system over time. It may also void your warranty. In older vehicles, the engine can make an audible "knocking" or "pinging" sound. Many newer vehicles can adjust the spark timing to reduce knock, but engine power and fuel economy will still suffer.

Why does higher octane fuel cost more?

The fuel components that boost octane are generally more expensive to produce.

Can ethanol boost gasoline's octane rating?

Yes. Ethanol has a much higher octane rating (about 109) than gasoline. Refiners usually blend ethanol with gasoline to help boost its octane rating—most gasoline in the U.S. contains up to 10% ethanol. Blends of up to 15% ethanol are available in some areas, and several manufacturers approve using this blend in recent-model vehicles.

Why is high octane fuel important?

In these engines, high octane fuel will improve performance and fuel economy.

Can you use 85 octane fuel in a car?

This is not true for modern gasoline engines. So, unless you have an older vehicle with a carbureted engine, you should use the manufacturer-recommended fuel for your vehicle, even where 85 octane fuel is available.

What is the octane rating of gasoline?

The octane rating of gasoline essentially tells you how much the air-fuel mixture can be compressed before it will spontaneously ignite. Gasoline with an optimal octane rating performs best in an engine designed to run on that octane level. Refiners aim to produce gasoline that has this optimal octane rating so it will meet the specifications for the most kinds of engines. That's what ethanol is such a big deal - it's partly used to increase the octane rating of the gas. Ethanol free gasoline has to have other things added to it to make up the octane difference.

Does octane increase explosion?

So, octane does not enhance the explosion in ...

What is the octane number of gasoline?

The octane number of gasoline is a measure of its resistance to knock. The octane number is determined by comparing the characteristics of a gasoline to isooctane (2,2,4-trimethylpentane) and heptane. Isooctane is assigned an octane number of 100. It is a highly branched compound that burns smoothly, with a little knock.

What are the compounds in gasoline?

Smaller amounts of aromatic compounds are present. Alkenes and alkynes may also be present in gasoline. Gasoline is most often produced by the fractional distillation of petroleum, also known as crude oil (it is also produced from coal and oil shale). The crude oil is separated according to different boiling points into fractions.

Does high octane gasoline outperform regular gasoline?

High octane gasoline does not outperform regular octane gasoline in preventing engine deposits from forming, in removing them, or in cleaning the engine. However modern high octane fuels may contain additional detergents to help protect high compression engines. Consumers should select the lowest octane grade at which the car's engine runs without knocking. Occasional light knocking or pinging won't harm the engine and doesn't indicate a need for higher octane. On the other hand, a heavy or persistent knock may result in engine damage.

Is heptane a branched compound?

It is a highly branched compound that burns smoothly, with a little knock. On the other hand, heptane is given an octane rating of zero. It is an unbranched compound and knocks badly. Straight-run gasoline has an octane number of about 70.

Does straight run gasoline have knocking properties?

In other words, straight-run gasoline has the same knocking properties as a mix ture of 70% isooctane and 30% heptane. Cracking, isomerization and other processes can be used to increase the octane rating of gasoline to about 90. Anti-knock agents may be added to further increase the octane rating.

What is 87 octane?

Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.

What makes a high performance engine?

So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance.". The disadvantage is that the gasoline for your engine costs more.

What is the compression ratio of an engine?

The amount of compression is called the compression ratio of the engine. A typical engine might have a compression ratio of 8-to-1. (See How Car Engines Work for details.) The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because ...

Does heptane gas have compression?

It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.

What is octane in gasoline?

Thanks to EPA regulations of mobile sources, air pollutants have been reduced by millions of tons in the urban environment. Several EPA fuel regulations have concerned octane. Octane is a gasoline additive that is needed for the proper functioning of modern engines. Octane sources have taken many forms throughout the years, both renewable and petroleum-based. They include lead, methyl tertiary butyl ether (MTBE), benzene, toluene, ethyl-benzene and xylene (BTEX), and ethanol (a biofuel). As adverse health and environmental consequences have been discovered for lead and petroleum-based octane providers, they have been removed from the fuel supply or decreased. Today, there are two primary sources of octane used in the U.S. gasoline supply, the BTEX complex (a petroleum refining product commonly referred to as gasoline aromatics), and ethanol.

What is octane used for?

Octane is a gasoline additive that is needed for the proper functioning of modern engines. Octane sources have taken many forms throughout the years, both renewable and petroleum-based. They include lead, methyl tertiary butyl ether (MTBE), benzene, toluene, ethyl-benzene and xylene (BTEX), and ethanol (a biofuel).

How to increase octane in gasoline?

Currently, there are two ways of increasing the octane content of gasoline: increasing the volume of gasoline aromatics or increasing the volume of ethanol.

How does lead affect gasoline?

Lead and various petroleum products have provided octane to gasoline for over 100 years, but evolving health and environmental concerns have led policymakers to reconsider the widespread use of many of these compounds. As the United States looks to reduce the greenhouse gas intensity of the transportation sector, increasing the octane value of gasoline is a promising avenue, as it would enable more fuel-efficient engines. But the health and environmental impacts of the octane sources that are used must be considered as well. By adding ethanol to finished gasoline, called “splash blending,” octane ratings can be increased while simultaneously lowering toxic octane sources.

What is the primary source of octane?

Today, there are two primary sources of octane used in the U.S. gasoline supply, the BTEX complex (a petroleum refining product commonly referred to as gasoline aromatics), and ethanol.

What chemical is used to reduce engine knock?

In 1921, automotive engineers working for General Motors discovered that tetraethyl lead (better known as lead) provided octane to gasoline, preventing engine knock.

When did the EPA mandate a phased in reduction of lead content in all grades of gasoline?

1973: EPA mandates a phased-in reduction of lead content in all grades of gasoline.

What is the octane rating of gasoline?

All states require gas pumps to be labeled with the correct octane level and nearly all states do regular testing to make sure gas stations are in compliance. A minimum 82 octane fuel is recommended for most vehicles produced since 1984. Older cars with carburetors could operate with lower octane fuel at higher elevations. Regardless of legality fuel with an octane rating of less than 82 is generally not offered for sale in most states. However 85 and 86 octane gasoline can still commonly be found in several rocky mountain states but availability is declining due to fewer cars with carburetors being still on the road and they are already gone in many states that previously sold it like Alaska, Maine and North Dakota.

Does Phillips 66 sell 91 octane?

93 is widely available. 91 octane is commonly sold as "premium" in the western, mountainous part of the state.

Does Kum and Go have 93 octane?

93 is available at select Kum & Go locations. 93 octane fuel may be available at certain locations in southern parts of the state.

Is 85 octane gasoline legal?

Regardless of legality fuel with an octane rating of less than 82 is generally not offered for sale in most states. However 85 and 86 octane gasoline can still commonly be found in several rocky mountain states but availability is declining due to fewer cars with carburetors being still on the road and they are already gone in many states ...

Overview

An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating. Octane rating does not relate directly to the power output or the energy content of the fuel per unit mass or volume, but simply indicates gasoline's capability against compression.

Principles

Measurement methods

Effects

Regional variations

See also

Further reading

External links