When you visit a gas station, you have many choices. If you are uncertain about what’s best, it can leave you very confused! For example, is unleaded fuel the same as regular fuel, and what is premium gas anyway?
In this article, I define both unleaded fuel and regular fuel. I then identify the differences between regular fuel and other types of fuel at the pump. At the end of the article, I will help you figure out what fuel is best for your vehicle.
Is Unleaded Gas the Same as Regular?
Yes, Unleaded gas is the same as regular gasoline since leaded fuel was outlawed in the 1970s due to neurological problems.
That being said, there are different levels of octane for unleaded gas, and some grades are higher quality than others. This is why it’s all the more important to understand the differences.
What is Unleaded Gas?
Unleaded gas has no lead. This was put into use in the 1970s to replace the leaded gasoline grade.
Overall, unleaded is safer for the environment and safer for motorists than leaded grade. It’s also more expensive to refine.
Lead was used, because it improved the octane level of the fuel. A higher-octane fuel meant that there were less instances of pinging or knocking during the combustion process.
The government decided it could no longer offer leaded fuel because it was causing neurological damage in people (especially children) and contributing to a higher amount of pollution in the air.
There are some older vehicles that’ll still need leaded fuel as well, as they use it primarily for race cars to improve performance.
What is Regular Gas?
Regular gas is classified as unleaded gasoline, and contains a lower octane rating than anything labeled as premium. It’s the grade of gasoline that’s used the most in vehicles today, and carries an octane rating of “87”.
Regular gas can be used in almost all vehicles on the road today, with the exception of high-performance models, or vehicles in the luxury category. Also, it’s the cheapest form of gasoline, at least among unleaded varieties.
Regular vs. Premium Gas
#1. Octane
There is a difference in the octane of regular and premium gas. Octane is the fuel’s characteristic of withstanding some combustion event. A combustion engine must compress air and fuel to be ignited.
Pre-ignition must occur at a specific point to avoid a prior combustion. When this happens, you will hear a knocking sound from the engine, and it will affect performance and ultimately result in engine damage.
Regular gas is usually rated at 87 octane, while premium goes higher, to 89-94 or higher. The higher the octane, the more of an ability is has to withstand pre-ignition to protect the engine.
#2. Price
Gas isn’t cheap anymore. There is no way to avoid paying for gas. But, regular unleaded will be much cheaper than premium fuel types. Generally, you will pay 20% more to put premium fuel into your car.
If you require premium fuel as required to operate your engine, the damage to the engine is insurmountable when compared to the small price differential for fuel. If you are routinely paying then it adds up!
#3. Engine Compatibility.
Many modern cars require regular unleaded gas. Regular unleaded gas is the right fuel option to get the best performance, for most cars, trucks and SUVs. That being said, many cars recommend that you use premium fuel.
If you have a luxury model or high-performance car, you might see premium fuel is recommended. If you are unsure, read the owners manual or ask your local dealership.
Regular Gas vs. E85 Gas
You may have seen that E85 gas is recommended for some newer models as well. What is E85 gas and how does it compare to regular? You also want to know if you can use these fuels interchangeably.
Ethanol is a renewable fuel source, derived from plant material also referred to as biomass.
Regular unleaded fuel actually has some ethanol in its formulation. In most cases, the fuel is referred to as E10, which means it is ten percent ethanol throughout the fuel. It gives the proper amount of oxygen to the fuel.
Newer vehicles can be classified as E85 flex fuel. This means regular unleaded fuel could be used, or you could use E85 fuel.
This blend is 85% ethanol and 15% gasoline. Ethanol burns quicker and is cleaner burning, but the downsides are it does not create as much energy as gasoline. Plus, it tends to be difficult to find unless you live in the Midwest where the product is commonly produced.
Why Is the Octane Rating So Important?
The octane rating of the fuel is one of the most important elements. This number indicates how the fuel reacts to being compressed in the engine. The higher the octane number, the more compression can happen before it detonates.
While detonating does happen at a certain interval to protect the engine, this is why motors are all rated to run on a certain octane fuel.
If your vehicle is designed to run on premium fuel, it may still run on a fuel with a lower octane, but the performance is not going to be the same, fuel economy may suffer, and you may have engine damage in the future.
How to Gauge Fuel Octane?
#1. Owner’s Manual.
The best way to confirm the correct octane rating is by referencing the owner’s manual. The owner’s manual should contain precisely what the manufacturer recommends. If you do not have access to the car manual, or can’t track it down, you can find it online.
It is worth mentioning that just because the manual recommends a specific type of fuel, that does not mean that is the only fuel you can use. However, if the only type of octane is dictated, I would recommend using the fuel the automaker designed and specified for your vehicle. They know what is best.
#2. Contact your Dealer.
If it is difficult to find, you can also reach out to your dealership or automaker through a contact link. You could obtain additional information to determine the best fuel that suits your needs, although it may take a little longer than the first two options.
A dealership would have the ability to search your specific vehicle for certain information. Again, following their recommendation is still your best option (especially if you intend to return to them for warranty repairs if something goes wrong) of course.
#3. Try It Out.
If the owner’s manual specifies fuel, then I would recommend using that type of fuel. However, if the owner’s manual gives you options, you can simply try them all and figure out which one best suits your preferences.
Ideally, you would try and get the fuel tank down to the near-empty level before switching to the different octane rating for comparison.
You may also find a situation when it makes sense to change the octane. For example, if your vehicle is in a situation were it is towing heavy loads or something else that is forcing the engine to do unusual amount of work at one time, upgrading to premium fuel temporarily could be beneficial.
Use good judgement, but also use the manufacturer’s recommendation in its best intended fashion.
Does A Car Go Faster By Switching To Premium Gas?
Your car is NOT going to go faster simply by putting premium gas in your vehicle. Octane rating is a related to the compression of fuel. Simply put, if octane rating is increased, it allows it to be compressed more, and further along its compression curve, before it detonates.
Since detonation can hurt an engine, we need to follow the octane rating recommended by the manufacturer.
What you might find by upgrading to premium fuel is a smoother running engine and much less wear and tear. You may experience an engine running a bit more efficiently, and premium fuel can provide protection from damage as well.
The opposite will be true if you downgrade octane ratings. Your engine will not be running as efficiently, so you may consume more fuel overall, making it add-up, but not correct for specific driving.
Can Using Premium Gas Damage My Car Engine?
You could run into engine damage if you use the wrong fuel (ex: you put diesel in a gas engine or vice versa). You would probably have a lot of problems, if not complete engine failure. This is typically not the case for using “wrong” octane ratings.
But car engines are tuned to run on a specific fuel octane. You might say you are doing your car a favor by simply going up to premium gas, but this is also not bad and potentially could do more harm than good.
Or you could have severely damaged (if not totally), if you were using lower octane fuel when your car requires premium. If your engine requires this extra protection, then it has to run properly comparable to the way an automaker designed.
You should not stray from the automaker’s guidelines if you want to potentially prevent damaging future performance of your engine, or very costly future engine failure.
Is it okay to mix gas types?
Yes, you can mix different gasoline types in your car. However, if you mix 2 types of gas together, then you will get an octane level that is right in between the two.
If your car runs on premium fuel, and you mix it with regular, you may see some issues.
What happens if I put the wrong gas in my car by accident?
If you put unleaded gas in a car made for premium fuel, then it may run poorly if you were to drive it hard.
You can expect to lose some power and acceleration, and you will get poor fuel economy as well. But if you accidentally put gasoline in a diesel car, you should not start the engine at all – you risk severe damage.
What happens if I accidentally put unleaded fuel in a premium car?
If you accidentally put unleaded into a car that calls for premium fuel, you may notice that the car does not seem to be operating at its best.
It may run a little rough, and you will notice a decrease in power and torque. If you do this by mistake don’t panic – just drive the car gently until you can refill it with premium fuel.
Is 87 octane the same as unleaded?
Yes. 87 octane is the same as regular unleaded gas. Generally, octane greater than 91 is considered premium gasoline. An octane rating of a fuel is a reflection of that fuel’s ability to withstand “knocking” or “pinging” during combustion.