Ever wonder if the type of gas you add to your vehicle matters? This article will help answer questions like this and more. After reading this article, you’ll have a better understanding of common fuel types, the average octane difference between types of gas, and the pros and cons of each.
Types of Gas
What's In This Post?
- 1 Types of Gas
- 2 Alternative Fuel Types
- 3 Services & Products to Help Improve Engine Life
- 4 FAQ
- 5 Key Takeaways
- 6 Final Thoughts
There are three main categories of gas types: Regular or Unleaded (low-grade), Plus (mid-grade), and Premium or Super Unleaded (high-grade), which have all been around since the early 1900s. There’s also Diesel fuel, but it’s different, and you should never use it in gasoline engines. Today, we also have E85 (flex fuel), making it difficult to know the best type for your motor.
Understanding Octane Ratings
The octane levels determine how well an engine can mix the air and fuel. Higher numbers mean more power, better fuel efficiency, and fewer chances of knocking sounds.
In the United States, we have gas with octane levels of 85 to 94, depending on the state and elevation. So if you live in higher elevations, you’ll typically have lower octane ratings than states at lower elevations.
So what’s the difference in octane levels? A higher number means the gasoline has additional oxygen blended with it, making the mixture of air and gas burn faster and easier, so you get more power from less fuel. Below are more details for each type of gas, along with some pros and cons.
Unleaded or Lower-Octane Fuel
Unleaded or regular gasoline typically has the lowest octane rating, and it’s the most common form of gasoline available today. You’ll find this grade of gasoline listed as 87-octane fuel.
- Cheaper than other grades of gas
- It doesn’t contain lead
- Contains cleaning additives
- May help cars run more efficiently in higher altitudes
- Not the best type of gas for high-end or European cars
- Not as efficient as premium grades
- Not great for turbo or high-performance motors
- It can cause engines to run poorly and even damage emission sensors
Plus or Mid-Grade
Mid-grade gasoline has an octane rating between 88 and 90. The extra oxygen helps make this gas more powerful than regular unleaded. As a result, it’s slightly more expensive than regular unleaded, but it’s still cheaper than premium grades.
- Great for high-performance vehicles
- Great for turbo motors
- It helps prevent knocking in older vintage motors
- More expensive than regular unleaded or low-grade gas
- Less efficient than super unleaded or premium grades
Premium or Super High-Octane Fuel
Premium or Super Unleaded gasoline is considered Higher-Octane Fuel and has an average of 91-octane or higher. It’s the highest quality fuel available and often used by race teams and enthusiasts because of its ability to produce more horsepower. Premium fuels also provide better performance in cold weather conditions.
- Highest quality fuel
- It helps reduce engine noises like pinging and knocking in older classic vehicles
- It performs better in cold weather conditions
- More expensive than other grades of gas
E85 or Flex-Fuel
This type of gas is a blend of 85% ethanol and 15% gasoline, allowing your vehicle to use either gas or ethanol. We’ll discuss ethanol a little later in this article. The price of corn determines the price of E85, which causes it to fluctuate more than traditional gas at times.
According to the historical price chart put out by macrotrends.net, corn prices are roughly $7.2575 per bushel. As a result, E85 costs about 21 cents per gallon less than regular unleaded gas when writing this article.
E85 isn’t as available as other fuel types since it has fewer filling locations across the United States. However, according to the U.S. Department of Energy, roughly 3900 gas stations across the U.S. provide E85.
- Generally cost less than regular low-grade gasoline
- It burns cleaner and doesn’t release as much pollution as other grades of gas
- It helps prevent pinging and knocking better than Plus and Premium
- It’s only available in a flex-fuel vehicle
- Lower MPG (miles per gallon) leading to more visits to the gas pump
- It’s not available at every gas station across the United States
Unlike other fuel types, diesel fuel has a lower octane level of 25 to 40 and is heavier than any other type of gas. Therefore, accidentally adding diesel fuel to a gasoline engine can lead to issues with your pistons, spark plugs, and valves. In some cases, having too much diesel fuel in a gas motor can lock your cylinders. Along with causing damage to the engine, diesel fuel can also destroy your catalytic converter.
Diesel fuel might be bad for vehicles that require other types of gas, but it’s excellent for cars designed to run on it. Below are some of the pros and cons of diesel fuel when used in the correct type of vehicle.
- Diesel burns at a different rate than other gasoline types leading to better fuel economy
- Produce lower emissions than gasoline-powered vehicles
- Currently priced higher than all other types of fuel
- Emits dirty black smoke from the exhaust that smells bad
Alternative Fuel Types
There are roughly six other sources to choose from besides the ones listed above. These include electricity, natural gas, propane, hydrogen, biodiesel, and ethanol. Each one offers its own set of advantages and disadvantages. So let’s take a closer look at each type to understand better which alternative fuels will work best for you.
Manufacturers use crops like wheat, corn, and barley to produce ethanol, and it’s commonly blended with gasoline to create an energy source known as E10. Ethanol is also known as “gasohol” because it contains 10% alcohol by volume. The advantage of this type of fuel is that it produces fewer harmful emissions than other gas types. It also reduces the amount of carbon dioxide released into the atmosphere.
Biodiesel isn’t the same as traditional diesel and typically comes from animal fat and vegetable oil. Biodiesel is a renewable source of fuel that uses up to 50 times less fossil fuel than conventional diesel. Meaning if you use biodiesel instead of diesel, you’ll reduce greenhouse gases by about half.
Hydrogen is another alternative option that comes from water through electrolysis. There are many benefits associated with using hydrogen, including reducing our dependence on foreign oil. However, there are still many challenges facing the production of hydrogen fuel. For example, hydrogen filling stations are not available everywhere yet.
One of the most accessible sources of fuel is electricity. Owning a vehicle that doesn’t require gas is helpful when gas prices are high, but there are drawbacks to running on electricity. First, they need access to particular power outlets which aren’t widely available when taking long road trips. Also, they aren’t very efficient, so they’re not as economical as other options. On a positive note, electric vehicles don’t produce any pollution or greenhouse gases.
Natural gas for cars is becoming more popular due to its low price, availability, and smaller gas tanks. However, methane emissions released by natural gas are harmful to the atmosphere. Another significant issue is that it takes longer to heat up and cool down than other fuel types.
Propane is clean-burning and emits only tiny amounts of pollutants which is good for the environment. However, there aren’t a lot of cars designed to use propane. Since they require large tanks, you’ll typically find propane used in larger fleet vehicles such as trucks or school busses.
Services & Products to Help Improve Engine Life
Below is a list of services we feel help improve the life of your engine when performed at the recommended intervals within the owner’s manual. But, of course, we’re not mechanics and recommend checking with a professional for detailed recommendations for the vehicle you drive.
- Tune-Up: Tune-ups should occur every 15,000 miles to ensure your engine continues performing its best. Tune-ups include checking the belts and hoses, changing spark plugs, and other essential things that need attention. Check out the post we wrote on tune-ups to learn more.
- Oil Changes: The type of oil you have will determine how long you go between oil changes. To keep your motor in excellent running condition, you should consider changing the oil and filter every three months or 5,000 miles for standard oil and every five months or 8,000 miles for synthetic blends. The length of time between changes might vary slightly depending on recommendations by service centers or details listed in your owner’s manual.
- Transmission Flush: To help prevent potential engine problems such as leaks and overheating, it’s a good idea to flush the transmission. Most service centers recommend flushing the transmission after your vehicle reaches 30,000 miles. To learn more, check out the article we wrote on transmission service.
- Radiator Flush: To prevent problems with corrosion in the different engine components, you should have the radiator flushed after your car reaches 100,000 miles. However, if you see any rust around the inside opening of the radiator before reaching 100,000 miles, you may want to speak with a mechanic to go ahead and flush the radiator.
- Engine Oil Additives: Adding an engine oil additive helps ensure all internal parts of the engine have better lubrication. There are multiple benefits to adding an engine oil additive. One is improved fuel efficiency by up to 5%. Check out the article we wrote on engine oil additives to learn more.
- Is it okay to use high-octane fuel in a car that doesn’t require it? Yes, it’s okay to use mid-grade or premium fuel in a vehicle that only requires regular unleaded or lower-octane fuel.
- Can adding diesel fuel to gas-powered engines cause damage? Yes, as mentioned in this article, it can cause a wide range of damage. Therefore, unless designed to handle diesel specifically, it’s best to avoid using it in your car.
- Is it better to have a diesel engine or gasoline engine in a 4-wheel drive? The answer depends on what kind of driving you do. A gasoline engine would be better if you drive off-road more and don’t haul a trailer. However, if you use your diesel truck to pull trailers instead of off-road mudding, a diesel would work best. Think of it like this; diesel engines are better for hauling trailers while gasoline engines are better for carrying heavy loads in the back of the truck. Ultimately the decision is up to personal preference.
- What is air fuel mixture? Air fuel mixture is key to the performance of an engine. It controls the performance and tuning by adjusting the fuel and air going into the combustion chamber.
- There are three main types of gas: Low-Grade (Unleaded), Mid-Grade (Plus), and High-Grade (Super)
- Unleaded fuel is your cheapest option.
- Mid-Grade and High-Grade fuels provide better engine performance
- Diesel burns cleaner than conventional fuel and is more fuel-efficient
- E85 or Flex-Fuel is made from corn and typically cheaper to use but not as available as other types of gas
- There are six additional types of fuel available: electricity, natural gas, propane, hydrogen, biodiesel, and ethanol.
- The engine will last longer when using the recommended type of gas listed in your owner’s manual
- Go with diesel-powered vehicles if you want more horsepower and gas-powered if you want something with lots of torque.
You should check the owner’s manual for your vehicle to determine which type of gas it requires to help it last longer. If you’re not driving a high-end luxury car or sports car, chances are you’ll have no problems using low-grade or regular unleaded gas. Be sure to check your owner’s manual or the sticker on the inside of the door to your gas cap to determine which type of gas is best for your vehicle.
Shawn LongmoreShawn is the founder of Auto Glass Locator and enjoys providing articles related to automotive parts and services. His mission is to make it easy for everyone to find all the information they need in one spot. Each year he continues to help more people find great deals on auto glass and other automotive services.
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