There are many different types and variations of fuels for cars than you typically see at gas station pumps. We have compiled the types of fuels used to power your car and discuss their differences and the benefits they offer for certain engine types.
There is a wide range of fuel types for cars, from oil to alcohol-based fuels. Gasoline is an umbrella term that encompasses all the different fuel types for cars today, including the mixes between gasoline and ethanol, diesel fuel, and various octane differences.
The type of fuel used in your car engine can impact the engine’s performance and the wear and tear the engine experiences depending on the type of work it performs. Certain fuels are better for power, while others are preferred for speed. Other fuels provide better engine protection and are used where reliability is paramount.
1. Leaded Gasoline
Leaded gasoline was the standard gasoline that was available at gas station pumps for decades in the early 1920s.
Lead additives were introduced to gasoline for the first time as early as 1921 to prevent knocking, sometimes called pinging, in gasoline-burning engines. The lead additive also improved the engines’ performance and fuel efficiency.
The lead additive was tetraethyl lead and provided a cushioning effect when burned in a gas engine’s cylinders. There were cleaner versions of alcohol-based fuels at the time, but the lead additive was cheaper, and the health and environmental conditions were unknown at the time.
Leaded gasoline was available in all octanes for modern vehicles and was the only fuel available at gas station pumps.
When the adverse effects of leaded fuels were realized, the world mobilized to find a better alternative. The first signs that the fuel was causing health and environmental problems were shown by studies conducted in 1969.
The leaded fuel could not be simply stopped but had to be phased out to give car manufacturers time to modify engines for a new fuel type. Car manufacturers began this process in 1970, and Japan was the first country to completely outlaw this fuel in 1986.
Algeria was the last country to ban the use of leaded fuel in 2021, which has resulted in this fuel no longer being available globally.
2. Unleaded Gasoline
Unleaded gasoline was the world’s answer to the dangerous pollutants produced by burning leaded fuels. Unleaded gasoline does not contain tetraethyl lead and has become the standard fuel available at gas stations today.
The change to unleaded gasoline took more than 50 years to complete since the change had to be phased in. Vehicle engines designed to run on leaded fuel could not run on unleaded fuel.
This required leaded fuel to be available until the old cars running leaded fuel were no longer being used. Car manufacturers needed time to produce enough new generation engines for the new unleaded fuel.
At the same time that the negative effects of leaded fuel were being discussed, new environmental controls regarding the emission of other harmful gases from cars came under the spotlight.
New environmental controls required cars to be fitted with catalytic converters to reduce harmful emissions. Catalytic converters do not work with leaded fuels, which was another motivation for car manufacturers to switch to engines designed for unleaded fuel.
3. Regular 87 Octane Gasoline
Regular is a term given to the lowest octane fuel offered at gas stations. The “regular” designation is related to the cost of the fuel, which is directly related to the octane level.
Octane is a measure of the quality of the fuel, its burning efficiency in a gasoline engine, and the performance it offers the engine. Most gas stations offer Regular, Mid-grade, and Premium fuels.
Lower octane fuel such as Regular 87 is a less stable and burns unpredictably in high compression high-performance engines. 87 Octane does not provide the same power and performance as higher octane fuels.
The instability of low octane fuels can result in uncontrolled or spontaneous ignition of the fuel in the engine cylinders resulting in significant damage to high-performance engines over time.
Many cars using computer-controlled ignition can adjust timing and sparking to limit spontaneous combustion, but it results in higher emissions and lower engine efficiency.
Regular gasoline is usually cheaper than the other grades or octanes of fuel sold at gas station pumps.
4. 89 Octane Plus Gasoline (Mid-Grade)
Mid-grade gasoline is typically 89 octane but can be 90 octane in certain regions. Certain cars, such as SUVs and modern pickup trucks, benefit from the higher octane fuel.
The 89 octane benefits improved fuel efficiency, less wear and tear on the engine, and more power from the fuel.
Most car manufacturers that recommend a mid-range fuel for their vehicles state that regular 87 grade can be used in these vehicles, but you cannot expect the same performance with this lower octane fuel.
In most cases, vehicles that use 87 octane fuel can use 89 octane fuel without any damage, but there will not be the same performance increase as an engine designed for 89 octane. Using a higher octane gasoline in a car designed for a lower octane will not improve performance; you will simply be paying more for the gasoline.
If you have a vehicle designed for 89 octane gasoline, you can use 87 octane, but you will notice performance degradation in the vehicle and a lower fuel economy.
5. Premium Gasoline 92 Octane
Premium gasoline is typically between 91 and 93 octane, with the average being 92 octane. Premium gasoline is the most expensive fuel sold at gas station pumps, with mid-grade and regular-grade gasoline being cheaper.
Premium octane fuel is more stable and limits the potential of pre-ignition or spontaneous ignition in the engine cylinder. The higher octane also gives a cleaner, more powerful burn than lower octane fuel.
Cars with high-performance engines are designed to use premium-grade fuel with higher octane. Using lower octane fuel in these engines can damage the engine and result in costly repairs.
If the manufacturer stipulates that your car should use premium-grade fuel, you should only use this fuel and never use a lower octane.
Cars designed for lower octane fuels can use premium-grade high octane gasoline without sustaining damage, but the engines are not designed to use the advantages of high octane fuel. The higher octane, therefore, offers no performance benefit but costs significantly more to fill your tank.
6. 93 Octane Gasoline
93 Octane gasoline is higher octane than premium gasoline, which can be between 91 and 93 octane. 93 octane gasoline is on the higher end of the scale and is often referred to as ultra-premium or super-premium gasoline.
Cars with high-performance engines have higher compression ratios, which could cause unpredictable ignition of lower octane fuel in the engine’s cylinders. Turbochargers and high-performance fuel injectors also require higher octane fuel.
While using a high octane fuel such as 93 in an older car will not harm the engine, using a lower octane fuel in an engine designed for high octane fuel can cause major damage to the engine.
7. 95 Octane Gasoline
Gasoline with a 95 octane is expensive and designed for use in cars with high revving, high-performance engines. Carse such as Porsches and Ferraris would fall into this category and other sports car style vehicles.
The higher octane offers a better burning fuel that is less prone to incorrect ignition in high compression engines.
If the manufacturer recommends that a 95 octane fuel is used in the engine, you should only use this octane for your vehicle.
95 Octane fuel is often used in coastal regions, whereas some car manufacturers recommend running 93 octane at higher altitudes. The slightly lower octane fuel burns more effectively and efficiently at high altitudes than 95 octane fuel.
8. E85 Or Flex-Fuel
Ethanol is often blended with gasoline as a fuel additive to change the characteristics of the fuel for specific locations.
E85 or flex-fuel is a blend of ethanol, a plant-based fuel, and gasoline, a petroleum-based fuel. The ethanol is added to the fuel to lower emissions and improve characteristics such as cold-weather starting.
Vehicles designed to accept fuel with high levels of ethanol are called Flexible Fuel Vehicles, or FFVs. These vehicles can utilize blended fuels where the ethanol component can be as much as 85% of the fuel.
E85 can contain anywhere from 51% to 83% ethanol. The amount of ethanol can be changed from season to season to canter for changes in climate between winter and summer.
FFVs have some engine and fuel system adaptations to allow them to use E85 fuel and can develop more torque and power than running these engines on gasoline.
The main disadvantage of vehicles that use E85 fuel is that they can be between 15% and 27% less fuel-efficient than gasoline-powered cars. This is mostly due to the lower energy-per-volume of ethanol compared to gasoline.
Most FFVs can run on gasoline or flex-fuel, but you should never put flex-fuel in a vehicle designed to run on gasoline.
9. E15 Gasoline
Most gasoline has some amount of ethanol blended into the fuel as an additive or alternative fuel. When the amount of ethanol added to the fuel becomes significant, affecting a motor vehicle engine, it is given an “E” designation.
E15 gas is a blend of 15% ethanol, and 85% gasoline and typically has a slightly higher octane of 88 compared to regular gasoline, which generally is 87 octane. Gas stations often drop the “E” on the fuel name and market E15 as “Unleaded 88 Octane.”
This is because most vehicles manufactured after 2001 can utilize E15 fuel without any special modifications. Vehicles designated as FFVs can use E15 gasoline without any problems.
Certain vehicles such as motorcycles, offroad vehicles such as ATVs and snowmobiles, and vehicles with heavy-duty engines such as school buses are not allowed to use E15 fuel due to lack of testing.
Diesel is technically not gasoline, but it is used as an alternative fuel to power our vehicles and deserves to be mentioned when discussing types of gasoline for cars.
There are many forms of diesel; some manufactured from petroleum and some from biomass. In order to distinguish between the diesel types, diesel made from petroleum is often called petrodiesel or simply diesel, while other diesel forms are termed biodiesel.
Petrodiesel is a byproduct of the manufacture of gasoline. In the US, diesel is often referred to as ULSD or Ultra-low sulfur diesel.
Diesel is less refined than gasoline and requires a diesel engine to burn the fuel. Diesel engines use compression to ignite the diesel fuel rather than the typical spark from a spark plug in a gasoline engine.
Engines designed to run on gasoline can be irreparably damaged if diesel fuel is put into the tank instead of gasoline. Diesel is also much thicker than gasoline and will clog fuel lines, filters, and fuel injectors.
Diesel engines can be severely damaged if gasoline is put in the tank rather than diesel fuel. Diesel engines rely on the additional lubrication that diesel fuel provides and can seize if run on gasoline. The gasoline will also damage the fuel pump and injectors.
Biodiesel is the broad term given to non-petroleum-based diesel fuel. Biodiesel can be manufactured from plant-based oils such as sunflower, peanut, or soybean. In some cases, animal fat or tallow is also used to manufacture biodiesel.
Most diesel car engines cannot run on pure biodiesel without modification. As a result, most biodiesel for motor vehicles is a blend of biodiesel and petrodiesel. In some cases, the petrodiesel can be as low as 10%, but the engine must be designed to run on this fuel.
Most diesel engines are designed to run on petrodiesel or biodiesel/petrodiesel blends. You should not run these engines on pure biodiesel, as damage can result.
While there are cost differences in the types of fuel for cars, motorists should be more selective about the fuels they use to power their cars. The choice should not be price-driven, but what fuel is the best for the long-term benefits for your car’s engine.
Using the right fuel in an engine designed for that fuel will make your car last longer with less expensive repairs required over the life of the car.