I realized the other day that I should be using at least 91 octane gas in my car. Right now I have about 1/4 tank of 87 octane. Is it a good idea to put in 94 oct so it averages to higher than 91?
Octane
- Thread starter WinkOsmosis
- Start date
Gas stations? Some have the regular 3 (87, 91, 93), whereas some have 5 diff. grades, like 87, 89, 91, 93, 94, etc, or even 100.
There are gas stations in California that sell 100 octane, there is one right around the corner from me. It is a 76 station.
Evadman
Administrator Emeritus<br>Elite Member
- Feb 18, 2001
- 30,990
- 5
- 81
There is a 76 station near me that sells 104 octane for $3.59 a gallon.
For those in my area, it is at Barrington rd and rt 19 in Schaumburg IL.
BTW, you need not run 91 octane unless you are having detonation problems. If I go easy on the throttle, I can run regular 87 in mine.
For those in my area, it is at Barrington rd and rt 19 in Schaumburg IL.
BTW, you need not run 91 octane unless you are having detonation problems. If I go easy on the throttle, I can run regular 87 in mine.
Yeah, about 10 of them. Every other state has 93 or better at every pump, but we're stuck w/ 91 for no reason.
not a big deal to mix. you can even get an octane boost if you guys wish from any auto parts store and use that to boost it. Not sure if it will make much of a difference unless you do a lot of heavy driving such as off roading or have a supercharged or like car. I would stick to whatever the manual prescribes personally.
Excellent suggestion..............actually, consistent using of higher octane gas than is required can lead to quicker carbon buildup in the cylinder and head. Octane is a measure of the gasoline's resistance to spontaneously igniting under pressure. The higher the octane rating, the higher the compression the gasoline can withstand before it explodes without a spark.
In other words, higher octane gas is more resistant to burning. That is all. The reason higher octane cars run faster, quicker, etc. is they have higher compression ratios and more aggressive timing settings, all putting more squeeze on the gasoline.
Using high octane in a normal lower compression-engine car is pointless unless you like making the oil companies richer........and paying much more for a couple of pennies of octane booster.
?? What do you mean you get lower gas milage with higher octane gasoline?
If anything, using regular over premium is going to lower his milage because his ECU will be retarding the timing due to the knock...
The Stigenator
Lifer
- Oct 9, 1999
- 15,216
- 3
- 81
I use 91 octane on my bike. It recommends 87 but I use the higher octance because it makes the bike run cooler at normal idle and at higher rpm's the bike still has a lot more umph.. With 87 octane I find 8000 rpm to be a bother but with 91 I can hit 10K on first gear and it would still be pulling..
Somehow in this case the higher rpm's runs better with 91.. so I run that.. 87 and 91 are fine at lower rpms (7K and below).
Somehow in this case the higher rpm's runs better with 91.. so I run that.. 87 and 91 are fine at lower rpms (7K and below).
I can't speak for certain about his particular car. I understand that most cars adjust for the octane. There is more energy in a gallon of regular than in a gallon of premium and most cars will go farther on it. As C'DaleRider said, high octane doesn't burn as well. The reason is because stuff that doesn't burn is added. If it doesn't burn it doesn't make the car go. Imagine pure gas and gas with 10% water. You'll get better milage on the pure gas.
StageLeft
No Lifer
- Sep 29, 2000
- 70,150
- 5
- 0
That would be true in a normal vehicle but a car that requires premium will work less efficiently running on it. The difference in horsepower can be significant and although ounce per ounce premium has less energy than regular, when running regular an engine tuned for premium will run significantly less efficiently, reducing the distance driven per volume of gasoline.
Octane can not be measured by simple averaging of two octanes. You have to use a formula to determine what the new octane would be. You can't just average the two because octane is measured a certain way. Google octane ratings or search www.corral.net/forums.
But a 240 SX likely recommends regular, so what Moonbeam said is correct. A car designed to run on regular will most likely get worse gas mileage and more carbon build-up if you run premium in it.
Higher octane does burn slower.
Here is basically why: The difference between a high and low compression engine is the higher compression engine will be squeezing more fuel/air mixture into the same space. Since more fuel/air mixture will contain more heat molecules, the mixture will be more likely to detonate and will burn more quickly. Ideally, you want the explosion to last long enough to drive the piston all the way down, not go "poof" at the top of the power stroke and let momentum push it the rest of the way. Not to mention that since most engines fire the plug anywhere between 32 and 40 degrees BEFORE TDC (top dead center), you don't want the mixture to be so flammable that it explodes immediately and tries to kick the piston back the way it's coming from, which is exactly what detonation does.
So, gas is formulated to explode/burn at a certain rate that will let the engine take the best advantage of the explosion. Since a lower compression engine isn't squeezing the mixture as tightly, it needs to be a bit more flammable than a higher compression engine does, so it won't be still exploding after the piston reaches BDC(bottom dead center) and then on the exhaust stroke the piston pushes pure fire out the exhaust port.
You can see what that will do by retarding your timing way too much and watching your manifolds turn cherry red. (not recommended)
No car requires premium unless it pings.
Here's what the Federal Trade Commission ways about it:
The Low-Down on High Octane Gasoline
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."
For More Information
The FTC works for the consumer to prevent fraudulent, deceptive and unfair business practices in the marketplace and to provide information to help consumers spot, stop and avoid them. To file a complaint or to get free information on consumer issues, visit www.ftc.gov or call toll-free, 1-877-FTC-HELP (1-877-382-4357); TTY: 1-866-653-4261. The FTC enters Internet, telemarketing, identity theft and other fraud-related complaints into Consumer Sentinel, a secure, online database available to hundreds of civil and criminal law enforcement agencies in the U.S. and abroad
Here's what the Federal Trade Commission ways about it:
The Low-Down on High Octane Gasoline
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."
For More Information
The FTC works for the consumer to prevent fraudulent, deceptive and unfair business practices in the marketplace and to provide information to help consumers spot, stop and avoid them. To file a complaint or to get free information on consumer issues, visit www.ftc.gov or call toll-free, 1-877-FTC-HELP (1-877-382-4357); TTY: 1-866-653-4261. The FTC enters Internet, telemarketing, identity theft and other fraud-related complaints into Consumer Sentinel, a secure, online database available to hundreds of civil and criminal law enforcement agencies in the U.S. and abroad
Scarpozzi
Lifer
- Jun 13, 2000
- 26,392
- 1,780
- 126
That's the way to be. Use regular unless you get ping...better known as spark-knock. You won't have that problem with low-compression 4 cylinder cars as much. You will start to have those problems with some of the V6 and inline 6 models depending on how efficient they can burn fuel.... (that all depends on how much pressure and the temp. of the fuel when it ignites)
California does suck....most everywhere....all the last 20 pumps i have gone too....all have max octane of 91
A quarter tank of lower octane gas isn't going to hurt anything. Just start using the 91 or whatever, don't worry about doing math.
Around here, the gas stations have 87, 89, and 93. I put in 93. There IS a noticeable difference in the way the engine feels. Amazing.
TRENDING THREADS
-
Discussion Zen 5 Speculation (EPYC Turin and Strix Point/Granite Ridge - Ryzen 9000)- Started by DisEnchantment
- Replies: 25K
-
Discussion Intel Meteor, Arrow, Lunar & Panther Lakes + WCL Discussion Threads
- Started by Tigerick
- Replies: 23K
-
Discussion Intel current and future Lakes & Rapids thread- Started by TheF34RChannel
- Replies: 23K
-
-
Facebook
Twitter