The truth about gasoline

[Reg Saretsky]

[edit] Lead

The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early (pre-ignition or detonation) causing a damaging "engine knocking" (also called "pinging" or "pinking") noise. Early research into this effect was led by A.H. Gibson and Harry Ricardo in England and Thomas Midgley and Thomas Boyd in the United States. The discovery that lead additives modified this behavior led to the widespread adoption of the practice in the 1920s and therefore more powerful higher compression engines. The most popular additive was tetra-ethyl lead. However, with the discovery of the environmental and health damage caused by the lead, and the incompatibility of lead with catalytic converters found on virtually all automobiles since 1975, this practice began to wane in the 1980s. Most countries are phasing out leaded fuel; different additives have replaced the lead compounds. The most popular additives include aromatic hydrocarbons, ethers and alcohol (usually ethanol or methanol).
In the U.S., where lead was blended with gasoline (primarily to boost octane levels) since the early 1920s, standards to phase out leaded gasoline were first implemented in 1973. In 1995, leaded fuel accounted for only 0.6 % of total gasoline sales and less than 2,000 tons of lead per year. From January 1, 1996, the Clean Air Act banned the sale of leaded fuel for use in on-road vehicles. Possession and use of leaded gasoline in a regular on-road vehicle now carries a maximum $10,000 fine in the United States. However, fuel containing lead may continue to be sold for off-road uses, including aircraft, racing cars, farm equipment, and marine engines until 2008. The ban on leaded gasoline led to thousands of tons of lead not being released in the air by automobiles, and resulted in lowering levels of lead in people's bloodstreams.
A side effect of the lead additives was protection of the valve seats from erosion. Many classic cars' engines have needed modification to use lead-free fuels since leaded fuels became unavailable. However, "Lead substitute" products are also produced and can sometimes be found at auto parts stores.
Gasoline, as delivered at the pump, also contains additives to reduce internal engine carbon buildups, improve combustion, and to allow easier starting in cold climates.
In most of South America, Africa, and some parts of Asia and the Middle East, leaded gasoline is common.

[edit] MMT

Methylcyclopentadienyl manganese tricarbonyl (MMT) has been used for many years in Canada and recently in Australia to boost octane. It also helps old cars designed for leaded fuel run on unleaded fuel without need for additives to prevent valve problems.
There are currently ongoing debates as to whether or not MMT is harmful to the environment and toxic to humans. However, US Federal sources state that MMT is suspected to be a powerful neurotoxin and respiratory toxin.

[edit] Dye

[hotrod_chevyz]

The performance difference between 87 and 92 isnt enough to pay the difference in price. Most cars in fact will show no difference at all when it comes to performance. Some cars with higher compression dont run right at all on 87 but usually when thats the case running 92 isnt much help.

[comp]

Originally Posted by hotrod_chevyz

The performance difference between 87 and 92 isnt enough to pay the difference in price. Most cars in fact will show no difference at all when it comes to performance. Some cars with higher compression dont run right at all on 87 but usually when thats the case running 92 isnt much help.

i have seen a big difference in many engines myself

[mr_mushroom]

i can tell the difference.
it's not an extra $.20 a gallon worth it IMO.
i get really low mileage so it's just pointless to drive high-octane gas.

[1993LUMINATOR]

and that is an interesting read, l'v mixed UPI 89regular with 91oct Shell a half half mix l have the time l'll see if theres a difference and actuly my engnie did work better l got 2-3mpg better l have the digital gauge determins rough MPG l did the same strech of road same speed same tempature same barametric prssure same sunny day. l knwo theres mythes but hey whatever you want to belave or whatever suites you better my driving habbits and vechials l drive mostly fullsize cars and pick-ups highway and backroads l'm a country guy

[WickedOne]

I would love it if someone could tell me wether or not all gas companies were putting out the same quality gas. For example: does my local gas station's 87 octane compare to say Chevron's 87 octane?

[dlog]

Look into Chevron's refining process, you might find your answer there....

[Cadillakin'98]

Some may argue it's all psychological but I swear I can tell a difference in different gas companies. Really there are only 2 that stand out to me, Chevron (which I partially dislike but like at the same time) and Shell (my prefrence). Also, it seems to me that "Sam's Club gas or Tom Thumb (grocery store) gas are "dirtier". And I swear I got ...crappier gas mileage using that cheap crap. I used to drive 250 to 300 miles a day, I would always reset my trip meter at every fill up, and if I used that discounted gas (Sam's or grocery store) I would be filling up ATLEAST 50 miles sooner than I normal would have to.

[Densis]

Originally Posted by GMMerlin

Here is some info about gasoline


A number of myths about octane have grown over the
years. There is a widespread perception that the greater the
octane the better the performance. However, once enough
octane is supplied to prevent engine knock, there is little, if
any, performance improvement. One exception to this would
be in vehicles equipped with knock sensors. In these vehicles,
if octane is insufficient, the computer will retard the timing to
limit engine knock. If the vehicle is operating in the “knock
limiting” mode (retarded timing), using a higher octane fuel will
allow timing to be advanced, resulting in some level of
performance increase. However, even in these vehicles,
tests have shown that there is no perceptible performance
improvement from using a fuel of higher octane than that
recommended by the vehicle manufacturer.
Another myth is that using a higher octane fuel will result
in improved fuel economy (increased miles per gallon). Octane
is nothing more than a measure of anti-knock quality.
Fuel economy is determined by a number of variables including
the energy content of the fuel. Some premium grades of
fuel may contain components which increase energy content.
In those cases, fuel economy may improve slightly as a result
of higher energy content, but not as a result of the higher
octane. Two fuels of identical octane could have different
energy content due to compositional differences.
Consumers need only use a gasoline meeting the
vehicle manufacturer’s recommended octane levels. If engine
knocking occurs on such fuels and mechanical causes
have been eliminated, then the consumer should purchase
the next highest octane gasoline (above the manufacturer's
recommendation in the owners manual) that will provide
knock-free operation.

GO HERE FOR MORE INFO

Nihueovii perecheni!opcorn:

[comp]

Originally Posted by Densis

Nihueovii perecheni!opcorn:

say what

[azntech630]

higher octane will just destroy you engin period!! unless it was design for that

[Francis Paguio]

anybody knows where the location of PCV valve for a 6.0 liter 2000 Chevy Suburban

[MagicRat]

Originally Posted by azntech630

higher octane will just destroy you engin period!! unless it was design for that

No true. Back in the 1960's, some people accused high-octane fuel for burning the valves of low-compression engines. But I have never seen any solid evidence for this problem.

But since hardened valve seats became industry-standard in 1971, this problem never occurs.

Originally Posted by Francis Paguio

anybody knows where the location of PCV valve for a 6.0 liter 2000 Chevy Suburban

You will get a better answer by starting an new thread in the Suburban sub forum.
Click here
This particular thread has nothing to do with your problem.

[Blue Bowtie]

An interesting article on pump fuels, and how ethanol can make a lot more power:

http://www.hotrod.com/techarticles/h...uel/index.html

[igor@af]

We can't exactly have a discussion of "facts" on here... some users in this thread have made statements that are completely false as if they are fact.

Here's the difference between octane levels:

The higher an octane of the gasoline, the higher the temperature it requires for ignition. THAT IS IT.
You can think of it as being "less easy to detonate." This comes into play when the inside of the chamber gets very hot - essentially high compression scenarios, whether by piston/stroke design or forced induction. Knock, or pre-ignition, means the gasoline inside the chamber detonates before a spark is introduced, simply because the chamber is really hot from previous explosions. This causes serious damage to the engine and will lead to failure.

A car's ECU needs to be TUNED in order to take advantage of higher-octane gasoline than it was intended for - it will make absolutely no difference unless there is a map that can either dynamically adjust based on octane level, or a map specifically designed for a certain octane level.

This essentially means that drivers with cars that are stock need not waste any extra money for any octane level that is higher than the recommended octane in the car manual; it will not make any difference.