More Gasoline information
Even though many reports say so, fuel does NOT all come from the same place. And even though some of it can come from some of the same refineries, they have different additive packages that are specified by the different stations. The better stations like Shell, Phillips 66, Sonoco and BP have a MUCH better additive package put into their gas. It runs much cleaner than the other gasoline's.
There is also what we call "Government Gas" This is the gasoline that the Government stores in many different storage facilities all across the US in what is known as the "Federal gasoline and oil reserves". This is fuel that is stockpiled for use in emergency situations such as an oil embargo, or a hurricane that knocks out some refinery capabilities, or a war or some other emergency. They didn't use to stockpile much gasoline in the past because we were not using nearly as much fuel as we are now. Today's demand for gas leaves us with only about a 72 hour supply at any one time and the problem is NOT crude oil...it is refining capacity. The US has not built any new refineries in the last 20 years...so if something happens to ANY of the refineries, we will be in a dire shortage. The Government is now stockpiling gasoline reserves to try to make sure that we do not get into real gasoline shortages. The problem with this is that gasoline cannot be stored for much longer than 30 days before it turns stale and creates gum and varnish particles. on a molecular level, and these particles are what causes the engine damage and carburetor problems that we are talking about. The government must ROTATE this gas about every 30 days. Much of the "Government gas" is sold to many of the "Discount" gas stations at a lesser price than the fresh fuel from the refineries. That is why you see the Shell gasoline commercials that show the two engine valves in the ad. The valve out of the engine that used the Good gas (in this case Shell) does not show any signs of gum and varnish deposits on it, where the valve that was out of the engine that used the Gas from a DISCOUNT station, has a large amount of the gum and varnish and carbon deposits. this is all caused by old gasoline. Gasoline that is even older than that will cause not only this problem but is can also cause the piston and the cylinder to score and ruin the engine.
It is very difficult for people to believe that this is happening, because many of the internet sites tend to try to make you believe that the gas is the same no matter where you buy it. Usually these sites are backed by the discount stations who want you to buy their gas. Go to a Shell station and ask them for some literature on the difference between their gasoline's and the discount stations. You might even be able to go to their website and get some of this information.
This information is not information that the gasoline companies or the government want the general public to know. The reason that I know this gasoline issue is because I have gone to many ASDVANCED service schools where they have tested the fuel from different stations, and we actually had to tear down engines that were run on the different gasoline's and tell the instructors what gas was used in each different engine and what damage was done because of them This is a very comprehensive multi-day "Failure analysis" school that covered not only the different gasoline's, but also the different oils....mainly 2-cycle oils. And there is a lot of difference in the oils, too.
AT least 70 to 80% of ALL of our repairs are due to this problem.....Bad gasoline.
WE recommend that you DO NOT use REGULAR GAS at all but use AT least 89 octane mid-grade gas. The higher the octane, the more additives that are added.
In any case, I hope this sheds some more information to help you understand about gasoline a little bit more.
The reason that your owners manuals say to use 87 octane gas is because the government says they have to. The actual statement is that they have to tell customers that they can use, what is called, "Universal fuel" What is universal fuel. It is fuel that is available in 100% of the United States and Canada. And there are a few REMOTE areas of The United States and Canada that Mid-grade (89 octane) Gasoline is NOT available.
Also, when these manuals were written, gasoline was a lot better than it is now.
I agree that in an automobile you do not NEED to use Premium gas, But you will actually get better gas millage by using the 89 octane gas.
Actually the biggest difference between the 87 octane gas and premium gas or even 89 octane gas is the "Rate of Burn"
Regular 87 octane gas actually EXPLODES like a firecracker. All of the heat and power are transferred to the piston all at the same time. Wasting a lot of the power and creating an enormous amount of heat ...all at the same time. This heat usually cannot be dissipated through the piston to the cylinder and out to the cooling system fast enough to keep the piston from overheating. This is called "DETONATION". This overheated piston can melt and cause engine damage.
Premium Gasoline DOES NOT EXPLODE! It actually burns more like a sparkler... Very evenly. This allows the power and the heat to be transferred more slowly and the energy is not wasted....also the engine runs cooler. You get better mileage because of the more efficient burning of the fuel. And you do not risk melted pistons.
Now there is a twist to this for automobiles. Most of today's autos, are now computer controlled. and you DO NOT want to use Gasoline that is more than 89 octane. The computer will be fooled and the engine will not run right. Why can you use the 89 octane gas in cars that have the computer set for 87? It is because the Government and the oil companies got together a few years ago and have removed a lot of the additives that they used to put into the fuel. This was an attempt to keep the price of gasoline down. Although we don't realize it, the price of gas would be much higher if they still used all of the additives that they used to. The additives are actually one of the most expensive parts of gasoline. If you are old enough to remember "Leaded Gasoline" Lead was not only a lubricant, but it was also what we call an "Octane booster" It actually didn't BOOST anything. What it did was slow the rate of burn so it would not burn as fast. Leaded regular gasoline was 90 octane. When they took the lead out of the gas, it became 87 octane gas. In addition, this is one of the reasons that they always said DO NOT USE THE 87 OCTANE gas in the older engines...Because it would RUIN the engine. That is because these older engines were made to run on 90 octane gas.
The more additives you take out of gas, the faster it will burn. In fact you might be surprised to know that the 87 octane gas that we are using today is not really 87 octane at all. It is even less. But they do not want the general public to know this. It would start a real uproar. That is also one of the reasons that you MUST use the better gasoline's with the better additive packages and it should be 89 octane. Today's 89 octane burns more like the 87 octane of just a few years ago.
Actually, there are 3 different methods for determining and mainly for reporting the octane rating of gasoline.
Research Octane Number (RON)
The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.
90 Octane - petrol with the same knocking characteristics as a mixture of 90% iso-octane and 10% heptane would have an octane rating of 90.
Motor Octane Number (MON)
There is another type of octane rating, called Motor Octane Number (MON), or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load as it is done at 900 rpm instead of the 600 rpm of the RON. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally, fuel specifications require both a minimum RON and a minimum MON.
] Anti-Knock Index (AKI)
In most countries, including all of those of Australia and Europe the "headline" octane rating shown on the pump is the RON, but in Canada, the United States and some other countries, like Brazil, the headline number is XXXXX average of the RON and the MON, called the Anti-Knock Index (AKI, and often written on pumps as (R+M)/2). It may also sometimes be called the Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2.
Difference between RON and AKI
Because of the 8 to 10 point difference noted above, the octane rating shown in the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel. See the table in the following section for a comparison.
Back when the older manuals were written, we were using the older Octane rating. That means that if they suggested using 87 octane gas back then, that you should use 91 or 92 now based on the new (R+M)/2). Rating system.