What is E15 Gas?

Written by

CarParts.com Research Team

Automotive and Tech Writers

Updated on December 5th, 2024

Reading Time: 4 minutes
Summary
  • E15 gas is a type of gasoline that contains 15% ethanol and 85% unleaded gasoline.
  • Unlike regular unleaded gasoline with an octane rating of 87, E15 gasoline has an octane rating of 88.
  • It’s worth mentioning that even if E15 gas is better for the environment and boosts engine performance, it doesn’t work with every vehicle type.

E15 gas is a type of gasoline that contains 15% ethanol and 85% unleaded gasoline. It has an octane rating of 88, making it more powerful than regular unleaded gasoline with an octane rating of 87. It’s an eco-friendly alternative to other gasoline types because it uses less gasoline, substituting some with renewable ethanol.

The “E” in E15 indicates the presence of ethanol in the mixture. The E0 to E15 gas scale shows the percentage of ethanol in the gasoline, with E0 meaning 0% and E15 meaning 15%.

What Makes Ethanol Content Important for Gas?

Ethanol is a chemical that boosts the octane rating of your vehicle’s fuel. Generally speaking, the higher the octane, the better the engine performance. This doesn’t just increase power output and vehicle speed, but it also reduces emissions.

Despite ethanol’s benefits, too much of it can damage your vehicle. Most engines aren’t designed to work with ethanol content over a specific percentage. For example, vehicles that use E15 gas cannot use gasoline that’s made up of over 15% ethanol without running the risk of destroying the engine.

Is E15 Gas The Right Choice For You?

Check to see if your vehicle can use E15 gas in the first place. This can be done by consulting your owner’s manual or asking the dealership where you bought your vehicle.

Most vehicles manufactured in the United States after 2001 can handle E15 gas. Failing to check whether or not your vehicle can use E15 gas can cause severe engine damage and void car warranties.

Compatibility aside, it’s also important to determine whether or not E15 gas is suitable for your driving habits. It’s a good gas for drivers who regularly go on short trips since high ethanol content keeps your engine clean and minimizes emissions. However, it’s unsuitable for long drives due to the strain it puts on the engine.

The Pros of Using E15 Gas

The biggest advantages of using E15 gasoline are its ability to boost engine performance and reduce emissions. Other benefits include how cost-effective it is and how it supports local agriculture since ethanol is typically made from corn.

Powerful Performance

E15 gas increases your vehicle’s performance by boosting how much power its engine can generate. Not only does this increase the speed, but it also reduces engine knocking. This is largely due to the ethanol content and high octane rating of E15 gas.

Thousands of happy customers choose CarParts.com. Shop Now

Reduced Emissions

One of the biggest pros of using E15 gas is that it’s better for the environment than most gasoline types. This is because it uses more ethanol and less gasoline, reducing your vehicle’s reliance on fossil fuels to power it. It’s a more renewable source of energy that’s arguably better for the environment.

Cost-Effective

More often than not, E15 gas is cheaper than 87 octane gas. It uses less pure unleaded gasoline and substitutes it with ethanol, a renewable resource.

Supports Agriculture

Though this doesn’t benefit you directly, buying and using E15 gas on your vehicle supports local farmers since the ethanol in the gasoline is typically made using fermented and distilled corn. It’s important to keep farmers in business since produce is used in many ways outside the food industry.

The Cons of Using E15 Gas

E15 gas is good in many ways, but it isn’t perfect. Some of the downsides of this type of gasoline include how it is incompatible with many vehicles, can create contaminant deposits in the engine, can void engine warranties, and is generally less fuel efficient than unleaded gasoline.

Incompatible with Many Vehicles

Arguably, the biggest disadvantage of using E15 gas is that it only works with specific vehicles. Most older cars aren’t designed to handle gasoline mixed with ethanol. Doing so can destroy the engine. To complicate matters further, E15 gas isn’t available in every gas station.

Potentially Causes Contaminant Deposits

Gasoline isn’t water soluble. This means that ethanol can mix with contaminants and deposit them inside your engine, clogging vital components such as filters or injectors. You’ll need to take extra care of your engine if you use E15 gas.

Can Void Engine Warranties

Another disadvantage of using E15 gas is that it can void engine warranties since not all vehicles are designed to use it. Many warranties expect vehicle owners to use unleaded gas. Since certain complications such as contaminant deposits occur because of E15 gas, many warranties will not cover such damage, rendering them void.

Reduced Fuel Efficiency

Though E15 gasoline is more renewable and better for the environment than unleaded gasoline, it is less fuel efficient. Even if it’s cheaper, it is less fuel-efficient than regular gas, so you might need to make more frequent trips to the gas station. This can be a problem since E15 isn’t available at every gas station.

Frequently Asked Questions

E15 gas has an octane rating of 88 and contains 15% ethanol.

Here are some commonly asked questions about E15 gas.

Does E15 gas give more horsepower than most gasoline types?

Yes, E15 gas gives more horsepower than most gasoline types. This is because the gas has an octane rating of 88 and 15% ethanol, making it more resistant to premature fuel combustion. This increases its power output.

Is E15 gas the same as 87-octane gas?

No, E15 gas is not the same as 87-octane gas. E15 gas has an octane rating of 88 and contains 15% ethanol. On the other hand, 87 gas has an octane rating of 87 and typically contains no ethanol. 87 gas can also be used by most gas-powered vehicles whereas E15 gas can only be used by specific engines.

Is E15 gas the same as 89 octane gas?

No, E15 gas is not the same as 89 octane gas. Unlike E15 gas, 89 gas has an octane rating of 89 and typically contains no ethanol. Because of this, it can be used by most gas-powered vehicles – especially ones that benefit from higher octane fuel.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.