Do older cars run better on premium gas?
Is Higher-Octane Gas Better for Your Vehicle?
Your vehicle’s fuel level starts to go down and you know it’s time to fill up the tank. What you may not know is what high-octane fuel is or how it affects your vehicle. Unless you hear your car’s, engine knocking, there is no need to put a higher-octane gas in your tank. You may think that buying the higher-octane, or premium, gas is better for your car and will make it perform better. This is a common belief, probably based on the commercials selling gasoline. But if you look in your owner’s manual, you’ll find that the recommended gas for most vehicles is economy and standard, low octane.
Octane Levels
Most gas stations offer motorists three octane levels: regular (87), mid-grade (89) and premium (91-93). Some stations offer even more, including a super-premium, which is usually rated at 93. However, people usually mistake the grades as “good,” “better,” “best” instead of “regular,” “mid-grade,” “premium.” It can be confusing, especially when each gas station uses different names for their octane levels. Some stations name their mid-grade gas “special” or “plus” and their premium “super.” If you’re confused, just go by the octane level.
About Octane
What does octane measure? Octane ratings refer to the fuel’s ability to burn, or combust, in the engine. There really isn’t much difference between 83 octane or 95 octane (octane levels can vary from one gas station to the next), unless you are a chemist. Deciding which octane level to use depends on the compression ratio of your engine, so check with your dealer, local mechanic, or car manual.
Lower octanes (83-87) used in most cars are made to combust easily and more rapidly. Today’s cars with low-combustion engines also have computers that keep checking on the fuel/air mixture to eliminate the knocking (often the combustion of gas before the spark) that was common in older models.
Higher octanes (92-97), which burn evenly, more slowly, and have little chance of pre-igniting in the combustion chamber, which can improve a car’s acceleration and provide more mechanical energy to the drive train, hence more power.
Cleaning Properties
Does higher-octane gas clean engines better? Not really. The EPA mandates that all gas, no matter the octane level or brand, add cleaning agents. In other words, all levels of gas and all brands carry similar cleaning agents.
Will knocking harm my engine?
If you experience a light knocking sound from time to time, there’s usually no need to worry. It won’t hurt the engine, nor does it require a higher octane. If you hear a heavier or ongoing knock, however, don’t ignore it. Make the switch to the next higher grade octane and see if that takes care of it. If the knocking persists, see your trusty mechanic.
Can You Mix Regular And Premium Gas?
It’s a common question car owners ask – can you combine higher octane gasoline with regular gas in your car?
The article below will explore the differences between regular gas and premium gas and whether these two gas types can be mixed in your car engine.
Is It Okay To Mix Regular And Premium Gas?
The answer is yes and no. When you mix regular and premium gas, it may alter the performance of your vehicle. Cars that only run on premium fuel will have a reduced performance when that fuel is combined with a lower octane fuel. Other cars that use regular fuel may not cope well with higher octane gasoline.
Mixing regular and premium gas is not recommended; however, it is expected to have a minimal impact on your car’s performance. Cars that require premium fuel that are filled with regular fuel may see a decrease in performance and experience what is called “engine knock.”
There are also other factors to consider, which we will look at in more detail in the article below.
What Happens If You Mix Regular And Premium Gas?
Modern vehicles have advanced technology in their engines. Car engines that were manufactured within the last decade are able to detect which type of fuel has been used.
Older vehicles may develop an engine knock sound. This is because these older models have fixed fuel injectors and a fixed ignition time. Modern cars are able to adjust their parameters in accordance with the type of fuel that is used.
Mixing premium gas with regular unleaded gas will impact the octane levels and may influence your gas mileage in the long run, especially if your car requires premium fuel. If you were in a situation and had to mix fuel types, it is best to top up with your required fuel type when possible.
What Is Premium Gas?
Premium gasoline is a type of higher octane fuel. It is frequently used in high-performance vehicles. The octane level refers to how much compression the gasoline can withstand before igniting.
High-performance cars tend to have powerful engines. With higher compression ratios in these engines, they require a higher octane gas to work properly. This does not mean that regular gas will impact performance, though.
Octane rating: 91 and above
What Cars Require Premium Gas?
Below is a list of some cars that require a higher octane rating fuel in 2022.
- Jeep Renegade
- Mitsubishi Outlander
- Nissan Juke
- Buick Regal
- Buick Envision
- Subaru Forrester
- Chevrolet Malibu
- Mini COOPER.
What Is Regular Gas?
Regular gas, also called unleaded gas, is the most commonly used type of fuel in cars. “Regular” used to refer to leaded gasoline. However, lead has been banned from gasoline in most countries; therefore, regular gas refers mostly to unleaded gas with a lower octane level.
Octane rating: 87 (regular gas); 89 – 90 (Mid-grade gas)
What Cars Use Regular Gas?
Below is a list of luxury cars that use regular gas. It is the most commonly used gas.
- Hyundai Equus
- Lexus ES350
- Cadillac ATS
- Buick LaCrosse
- Volvo S60
- Lincoln MKX.
Most cars use regular gas, and the list would be incredibly long if we were to list every car that depended on regular unleaded gas.
How Do You Tell Which Type Of Fuel Your Car Uses?
You should consult your car manual if you are uncertain whether your car takes premium fuel or regular gas. If you have misplaced the manual, there should be a sticker inside the fuel door (the flap you open to get to the fuel cap and fuel tank). This sticker should indicate whether your car takes diesel or petrol, and also the octane rating required in the case of petrol.
Will Mixing Premium And Regular Gas Mess Up Your Car?
If a lower octane gas is mixed with a small amount of higher octane gas, then the octane level will remain low. If you were to mix a large volume of gas with a higher octane rating with gas with a lower octane rating, then the resulting octane level would be high.
So, is it okay to mix these gas types?
If your car requires a low octane gas, then mixing premium fuel with regular fuel will not do a lot of harm. However, it will also not offer any advantages, despite people believing that putting premium fuel in a regular gas car will offer better performance.
If you fill a car that requires premium gasoline with regular gas, ignition will not happen at the right time, and there is a small chance your vehicle will be damaged. However, modern engines are able to detect the octane ratings and can adjust performance and ignition accordingly.
Can You Switch From Regular To Premium Gas And Vice Versa?
It is not recommended that you switch between gas types.
Older cars that require higher octane fuels may instantly experience “knocking” when filled with lower octane gas. As mentioned already, more modern engines that require premium gas should be able to detect the octane fuel levels and adjust accordingly. So it will come down to the age of your premium gas car.
Cars that require regular gas are also unlikely to benefit from the use of premium gas. However, if you are in a pinch and it is the only fuel type available, you can fill up with high octane fuel.
FAQs
Does premium gas last longer?
Premium gas is only defined by the octane level, which determines the combustion in the engine. Premium fuel, therefore, does not last longer or make your car drive further.
There are things you can do to make your gas last longer, such as using a car with an excellent fuel economy, removing excess weight from the car, and giving your car regular maintenance.
Is unleaded gas regular gas?
Yes. Regular gas is also called unleaded gasoline. There is a worldwide ban on lead in gasoline by the United Nations, so therefore all regular gas is “unleaded.”
Is super unleaded the same as premium?
Yes. Premium fuel is often called “super” or “high performance” unleaded gasoline.
Is it bad to mix gas from different stations?
Different gas stations may use various additives in the fuel. However, there is no problem with mixing gas from different stations.
Author: DJ
Dave Junior is a hands-on automotive technician with experience in performing service, diagnostics, and repairs on domestic and imported vehicles. He enjoys writing and sharing his knowledge far and wide.
Choosing the right fuel will protect your classic
Ethanol and octane are separate issues. Let’s deal with ethanol first. From an automotive standpoint, there is nothing good about E10, the blend of gasoline with 10-percent ethanol sold at most pumps around the country. Ethanol is hygroscopic—it absorbs water. One could argue that the ability of gas to absorb a small amount of water is a good thing. If water is present and isn’t absorbed, it sinks to the bottom of the tank, where the pickup tube sucks it into the engine. But there’s a limit to the amount of water that can be absorbed before separation occurs, so when E10 sits in a humid environment, a corrosive mixture of water and ethanol can accumulate at the bottom of the tank.
These problems are exacerbated in lightly driven vintage cars that often have metal fuel tanks that might be poorly sealed due to degraded or missing emissions systems. This allows moist air into the tank, which gets absorbed by the ethanol in the gas, separates out as water, accumulates at the bottom of the tank, and causes running problems and rust in the tank. Ethanol also ruins rubber fuel lines, gaskets, and plastic and rubber fuel-system parts.
Fuel stabilizer used in vintage cars that sit for months, as I understand it, only prevents gas from going “sour.” It doesn’t alter ethanol’s hygroscopic properties or cause water that has already formed to magically dissolve.
If you can buy ethanol-free gas at a reasonable price, do it. Availability varies state to state. Websites like Pure-Gas.org and BuyRealGas.com make it easy to find ethanol-free fuel.
Now let’s move to octane. I always use the recommended octane for the car I’m driving—no more, no less. A modern car has a digital engine-management system with a calibrated spark-advance profile for a certain amount of octane in the fuel. In addition, most modern cars have a knock sensor, so if the engine is under load (low rpm, open throttle) and it begins knocking, the system should retard the ignition timing until the knocking stops.
In a vintage car without a knock sensor, especially one with a mechanically advanced distributor, regardless of what fuel is in the tank, if the car knocks under load, back off the throttle! Knocking (or pinging, as it’s sometimes called) is terrible for your engine and can blow holes in the pistons in short order. Especially in a vintage performance car with high-compression pistons, running on fuel with the recommended octane, with a distributor timed perfectly to spec, it’s still possible for the engine to knock under load. Try rotating the distributor to retard the timing. If it still knocks under reasonable loads, try switching to higher-octane gas, if you’re not already at the max. I set up my vintage cars for a tiny amount of pinging in a load situation (for example, uphill, wide-open throttle, one gear higher than I’d normally be in) but zero pinging otherwise.
In short, buy ethanol-free gas if you can, and buy gas with sufficient octane that your car doesn’t knock. If you’re forced to choose, take the higher octane to prevent knocking. But if the car doesn’t knock, go with the ethanol-free gas.
