Does it matter what type of gasoline I put in my car?

Question

The "super unleaded" and the "super supreme unleaded"? C'mon now, I've never heard of anybody said that their car was inoperable because they use regular unleaded instead of thier recommended super unleaded plus.

Answer 1

Are you tempted to buy a high octane gasoline for your car because you want to improve its performance? If so, take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to your owner's manual.

The only time you might need to switch to a higher octane level is if your car engine knocks when you use the recommended fuel. This happens to a small percentage of cars.

Unless your engine is knocking, buying higher octane gasoline is a waste of money, too. Premium gas costs 15 to 20 cents per gallon more than regular. That can add up to $100 or more a year in extra costs. Studies indicate that altogether, drivers may be spending hundreds of millions of dollars each year for higher octane gas than they need.

What are octane ratings?

Octane ratings measure a gasoline's ability to resist engine knock, a rattling or pinging sound that results from premature ignition of the compressed fuel-air mixture in one or more cylinders. Most gas stations offer three octane grades: regular (usually 87 octane), mid-grade (usually 89 octane) and premium (usually 92 or 93). The ratings must be posted on bright yellow stickers on each gasoline pump.

What's the right octane level for your car?

Check your owner's manual to determine the right octane level for your car. Regular octane is recommended for most cars. However, some cars with high compression engines, like sports cars and certain luxury cars, need mid-grade or premium gasoline to prevent knock.

How can you tell if you're using the right octane level? Listen to your car's engine. If it doesn't knock when you use the recommended octane, you're using the right grade of gasoline.

Will higher octane gasoline clean your engine better?

As a rule, high octane gasoline does not outperform regular octane in preventing engine deposits from forming, in removing them, or in cleaning your car's engine. In fact, the U.S. Environmental Protection Agency requires that all octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against the build-up of harmful levels of engine deposits during the expected life of your car.

Should you ever switch to a higher octane gasoline?

A few car engines may knock or ping - even if you use the recommended octane. If this happens, try switching to the next highest octane grade. In many cases, switching to the mid-grade or premium-grade gasoline will eliminate the knock. If the knocking or pinging continues after one or two fill-ups, you may need a tune-up or some other repair. After that work is done, go back to the lowest octane grade at which your engine runs without knocking.

Is knocking harmful?

Occasional light knocking or pinging won't harm your engine, and doesn't indicate a need for higher octane. But don't ignore severe knocking. A heavy or persistent knock can lead to engine damage.

Is all "premium" or "regular" gasoline the same?

The octane rating of gasoline marked "premium" or "regular" is not consistent across the country. One state may require a minimum octane rating of 92 for all premium gasoline, while another may allow 90 octane to be called premium. To make sure you know what you're buying, check the octane rating on the yellow sticker on the gas pump instead of relying on the name "premium" or "regular."

Answer 2

Manny hit the nail on the head. The famous pre-ignition cover up" knock sensors." If the cost does not outweigh the mileage gain higher octane fuel in a high performance motor is always better.

Take the new 3.5 V6 Camry Toyota motor for instance. It will run and operate on 87 octane but according to the operators manual you gain 10 hp. with 93 octane. Enter the famous knock sensor. Then the motor detects the slightest amount of pre-ignition or spark nock "wham" the knock sensor retards the spark and the extra10 horses is out to pasture.

Turbocharged motors are in desperate need of the highest octane fuel you can find because of the intense heat of compressed air caused by the turbocharger. The death rattle of spark knock is a given. Everyday new innovations are being created by the introduction of more efficient innercoolers to keep the compressed air coolerand spark nock away from the combustion chambers.

Higher octane fuels will be little or no benifit on older motors with mechanical loose tolerance pistions, rings and valves with compression ratios under 10.1.

Answer 3

Honestly you should just go by what the manufacture says in the guide.
But in reality it doesn't matter any more if you have a car after 1990. That's when they came up with knock sensors. Knock sensors controls the pistons in the cylinders from hitting the valves and breaking apart ,if you switch over from premium gas to regular gas or vice versa. What happens is that if your car says use premium, the engine timing is expecting the gas to mix with air at a certain time for combustion. Premium gas burns slow, regular gas burn really fast. SO when you put regular gas in an engine preset for premium gas combustion occurs faster than before when you had premium gas. But knock sensors automatically adjust the engine timing to compensate for the faster burning regular gas. But when this happens the actual car performance is usually affected.

I know this is complicated but i hope it helps though.

Answer 4

Most cars are fine with the regular unleaded, but some do knock and ping and need the plus. If your engine runs fine on regular, you won't need anything better and your fuel economy won't suffer.

Answer 5

most cars will run on the low grade fuel but there are some engines that must have premium fuel or they will start to ping. I know the Northstar engine in Cadillac needs 93 octane or better.

Answer 6

It depends what your car likes


My car only likes low grade unleaded, it does not like high grade

Answer 7

The premium gas is better for a car's engine. With using premium, you do spend a few cents more here and there, but you save a lot of maintanence on your car. I drive my car about 2,000 miles every two weeks and I rarely have to have maintenance. It is better for your car's efficiency to use the premium gas.

Answer 8

If they recommend super premium, then use it. Unless you want premature combustion...which isn't good for your engine.

Answer 9

use what the mfg. recommends