Gas Prices

[pegwinn]

I wonder the same. I also wonder why one place in the same state has gas at 2.99 and another at 3.19 ?

I can understand that the supply you paid big bux for needing to go down.... but man they raise gas prices faster than the fed and interest rates (when I am renegotiating a loan mind you).

 

[Annie]

I can understand that the supply you paid big bux for needing to go down.... but man they raise gas prices faster than the fed and interest rates (when I am renegotiating a loan mind you).

I'm having problems with a .20 local tax.

 

[fuzzykitten99]

I would love to hear the explanation for how running an engine on 4 octane lower could destroy it, especially if tuned to that lower octane. I have spoken to the guys that deliver fuel and they say that a lot of the time there isn't a difference, if there is a shortage they use whatever is available to fill the station's underground tanks. You end up paying 10 cents more a gallon for the same fuel....ooops.
If the recipe is different like aviation fuel you will have a drier mixture at 100 octane that if the tuning isn't changed could burn the valves. I used to run aviation gas that we would get from sumping the tanks of the trucks we fueled aircraft with. The water sinks to the bottom of the container so we could control it. My jeep would jump when punched but it idled like a Harley. I also added marvel mystery oil to it to try to lubricate it a little more. I finally started adding it in a ratio of 50/50 with regular gas and it ran OK, it was free at least.

High Octane fuel is HARDER to burn than lower octane fuel. Higher octane is to protect the engine from pre-detonation.

If you've read "How Car Engines Work", you know that almost all cars use four-stroke gasoline engines. One of the strokes is the compression stroke, where the engine compresses a cylinder-full of air and gas into a much smaller volume before igniting it with a spark plug. The amount of compression is called the compression ratio of the engine. A typical engine might have a compression ratio of 8-to-1. (See How Car Engines Work for details.)

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.

It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio. ...

link for more details: http://auto.howstuffworks.com/question90.htm

the same info, different site:

Why is octane important?
It may prevent engine damage. If a
gasoline is used with too low of an octane
rating than is required by an engine, then
engine knock may result. Heavy and
prolonged knocking or pinging may cause
power loss and may damage the engine.
...
How do I know what octane to
use for my vehicle?
Check you owner’s manual. Regular
octane is recommended for most cars.
However, some cars with high
compression engines, like sports cars,
older cars, and certain luxury cars (which is my car on both levels) , may
need mid-grade or premium gasoline.

link for the above info: http://www.oregon.gov/ODA/MSD/docs/pdf/gas_octane_guide.pdf

personally, i'll take the word of my mechanic with 40+ years of knowledge (as well as my vehicle's manufacturer) than some columnist in a newspaper who likely doesn't even know how to change his own oil. The cost to me at the pump is less than what I would have to spend for a repair bill at Andy's.

 

[fuzzykitten99]

in case those 2 weren't good enough for you, here's another:

http://en.wikipedia.org/wiki/Octane_rating

Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking. (Note that it is the absolute pressure (compression) in the combustion chamber which is important - not the compression ratio. The compression ratio only governs the maximum compression that can be achieved).

It might seem odd that fuels with higher octane ratings burn less easily, yet are popularly thought of as more powerful. The misunderstanding is caused by confusing the ability of the fuel to resist compression detonation (pre-ignition = engine knock) as opposed to the ability of the fuel to burn (combustion). However, premium grades of petrol often contain more energy per litre due to the composition of the fuel as well as increased octane.

 

[Jason Chambers]

The Net and it's information... Thier both right you know. It doesn't matter if you use regular (unleaded) or premium, it will not damage your engine. A mechanic telling you that is as full of it as the manufacturer's manual telling you to use ONLY premium... This is the AUTO INDUSTRY we're talking about... What do automobiles use? GAS! LOL! Do you see the correllation?

Just don't use leaded regular... :halo:

 

[Shattered]

I wonder the same. I also wonder why one place in the same state has gas at 2.99 and another at 3.19 ?

I actually asked a gas station owner this question... Here's your answer:

Me: Do you guys have magical gas or something?

Him: What do you mean?

Me: Well, your gas is $3.15, and half a block away, Mobile is at $2.99. Is yours magical?

Him: It's just a big game sometimes. We charge based on what we would have to pay if we needed a fill today.

Me: Well, this has been a fun game, but I'll go play at Mobile now. But, I'll take the coffee - thanks!



Oh, and it's currently $3.25 a gallon for 89 octane, and has been for weeks.

 

[misterblu]

in case those 2 weren't good enough for you, here's another:

http://en.wikipedia.org/wiki/Octane_rating

What year is the Caddy? Does it have a factory knock sensor?

Most newer vehicles may 'require' high octane, but tune themselves to run just fine on regular (at lower power outputs).

FWIW,


Jon

 

[dilloduck]

High Octane fuel is HARDER to burn than lower octane fuel. Higher octane is to protect the engine from pre-detonation.



link for more details: http://auto.howstuffworks.com/question90.htm

the same info, different site:


link for the above info: http://www.oregon.gov/ODA/MSD/docs/pdf/gas_octane_guide.pdf

personally, i'll take the word of my mechanic with 40+ years of knowledge (as well as my vehicle's manufacturer) than some columnist in a newspaper who likely doesn't even know how to change his own oil. The cost to me at the pump is less than what I would have to spend for a repair bill at Andy's.

Use the premium if you want to car to run better, quieter and last longer. There's lots of evidence pointing to damaged pistons and plugs from "pinging".
Why risk it for a few cents a gallon?

 

[red states rule]

gas prices here are still 40 cents per gal under their all time high

2.89/gal

 

[sitarro]

Mr. P stated it correctly back in post#10 and #12 of this thread. Newer cars have a timing and fuel mixture management system that would keep the engine from being damaged with the lower octane fuel(A huge 4 points lower). Older cars could be tuned to run on it, you would lose performance and even fuel mileage but damage the engine.... only if you allow it to "diesel" until it burst into flames like a cop's car I saw in Denver. He shut it off and ran into a building and it just kept coughing until a few minutes later when it blew up.

Liability keeps many from recommending things that might not be done correctly so Wikipedia will of course give you some definitions and won't go into the timing aspect.

 

[fuzzykitten99]

What year is the Caddy? Does it have a factory knock sensor?

Most newer vehicles may 'require' high octane, but tune themselves to run just fine on regular (at lower power outputs).

FWIW,


Jon

it is a 1992 Seville with a 4.9L V8 Northstar Aluminum B series engine block.

and the one and only time 87 oct was in it, it knocked like there were marbles dancing around. the 87 was put in on accident, and only 2 gallons were put in before my mom realized that she hit the wrong #. We took it to our mechanic to make sure there was nothing else wrong, and he said no, it was just the fuel. he drained the tank for us and put in 2 gallons of premium and said the knocking would eventually stop within 40-50 miles, which still isn't good for the car, but nothing we could do at the time.

 

[Adam's Apple]

We just got back from a trip down south and saw some pretty interesting things with regard to the price of gas. For example, at one exit we took to get gas, the Citgo station we used was charging $2.779/gal. for regular. Next door to this Citgo station was a McDonald's. Next door to the McDonald's was a BP gas station where regular was advertised for $2.939/gal.

At another exit where we stopped for gas, there were two gas stations directly across the road from each other. One's advertised price for regular was $2.989/gal. The other's was $3.099/gal.

When we got back home, regular was selling for $2.929/gal., which is the lowest it has been here for quite a while. It was not too long ago that we were paying $3.199/gal. for regular.

 

[sitarro]

We just got back from a trip down south and saw some pretty interesting things with regard to the price of gas. For example, at one exit we took to get gas, the Citgo station we used was charging $2.779/gal. for regular. Next door to this Citgo station was a McDonald's. Next door to the McDonald's was a BP gas station where regular was advertised for $2.939/gal.

At another exit where we stopped for gas, there were two gas stations directly across the road from each other. One's advertised price for regular was $2.989/gal. The other's was $3.099/gal.

When we got back home, regular was selling for $2.929/gal., which is the lowest it has been here for quite a while. It was not too long ago that we were paying $3.199/gal. for regular.

Just went by an Exxon with $2.70 regular. That is near Houston but from what I've heard it is cheaper in San Antonio.

 

[onedomino]

It is $3.38 for regular in Santa Barbara, CA., and we can see 7 or 8 huge oil platforms pumping away just offshore. Moreover, there are giant refineries close to here. Proximity to crude offers no relief on gas prices. Infact, there seems to be an inverse relationship: the closer the crude and refineries, the more expensive the gas.

 

[Mr. P]

It is $3.38 for regular in Santa Barbara, CA., and we can see 7 or 8 huge oil platforms pumping away just offshore. Moreover, there are giant refineries close to here. Proximity to crude offers no relief on gas prices. Infact, there seems to be an inverse relationship: the closer the crude and refineries, the more expensive the gas.

Ya know I been wondering about this...

In the past (40+ years), in Georgia we had cheap gas compared to the rest of the Country (for the most part). Now, we are as high as the Northern states. Makes ya wonder....

 

[Bonnie]

Prices here are going down each day, seems there are price wars now.... I see 2.85 for regular..... do I see 2.75??