More on Top Tier gasoline

On Thu, 31 Jul 2008 20:48:08 -0400, "Elmo P. Shagnasty"
> wrote:

>In article >,
> RT > wrote:
>
>> Buying higher grade gas than what the manufacturer of your car
>> specified is a waste of money.
>
>Define "grade".
>
>Gasolines with good additive packages that include good detergents to
>keep the fuel and combustion systems free of crap--now, those are good
>grades of gasoline.
>
>Funny thing--the manufacturer of your car doesn't specify what GRADE of
>gasoline you should use.
>
>I think you mean "octane" instead of "grade". Octane is not a measure
>of "goodness". It's a measure of the fuel's ability to resist knock and
>preignition. It's a property of the fuel--like color, it doesn't make
>the fuel inherently "better" or "worse". It's just a property.
>
>You've bought into the fuel company "premium" hype.

yeah yeah, I meant Octane.

"Elmo P. Shagnasty" wrote:
>
> In article >,
> RT > wrote:
>
> > Buying higher grade gas than what the manufacturer of your car
> > specified is a waste of money.
>
> Define "grade".


Grade is a term used by the petroleum refining industry to classify
types of gasoline. Basically gasoline is pumped into pipelines for
distribution, The grading system is a way to determine the value of
the product so that exchanges and sales can be made. Octane is the
main criteria for determining each grade.

Most people agree that if you go below the octane requirements for a
given engine that your mileage will go down and if you purchase
gasoline that goes above the octane requirements you won't get any
benefit. That seems like a pretty simple proposition but in reality it
is a whole lot more complicated. It's complicated by the fact that you
really can't be sure what the exact octane requirements are with out
careful real world testing.

>
> Gasolines with good additive packages that include good detergents to
> keep the fuel and combustion systems free of crap--now, those are good
> grades of gasoline.




>
> Funny thing--the manufacturer of your car doesn't specify what GRADE of
> gasoline you should use.
>
> I think you mean "octane" instead of "grade". Octane is not a measure
> of "goodness". It's a measure of the fuel's ability to resist knock and
> preignition. It's a property of the fuel--like color, it doesn't make
> the fuel inherently "better" or "worse". It's just a property.

I suppose you think there isn't any difference in quality of beef cuts
or that there is no such thing as "better" or "worse" when it comes to
types of wine?

Whether high octane is "better" or "worse" depends on what you are
interested in. Octane certainly is the single most important property
with respect to fuel economy. The reason the price is higher and
people pay more for premium is because A) It costs more to produce B)
In some vehicles it is cheaper to run using premium. C) regular may
cause damage to some vehicles. (note: I'm not saying B) applies to
every person who purchases premium and C) doesn't apply to very many
modern engines)

Here is a list what J.H.Gary's "Petroleum Refining Handbook" says
about the impact of octane on gasoline engines. The assumption here is
if everything else would be kept constant this is how these factors
affect a typical engine's octane requirements:

Combustion chamber deposits 0-12 RON
Altitude (air pressure) 3 RON for every 1000 ft.
Spark timing 3 RON for every 2 degrees
Engine speed 1 RON per 300 RPM
Engine Temperature 1 RON per 10°F
Intake air temp 1 RON per 20°F
Humidity 1 RON per 20%RH


He doesn't say anything about spark plug voltage and gap, EGR
concentration, and Air/Fuel ratio, or engine load which also are all
known factors that alter the engines octane requirements.
Engine management and it's sensors are designed to deal with a good
many of these factors so for instance timing is used to offset many of
the other factors. But sensors that measure these factors aren't
perfectly accurate or reliable. Just add up the possible normal
deviations and it is easy to see even in engines that are working 100%
as designed it is possible to deviate from the norm by more that 2
octane points. And what about the millions of cars that aren't
operating 100% as designed?

In isolation anyone of these factors is pretty simple to understand,
but when you combine everything together it becomes very complex
interactive system. Anyone (including the car's manufacturer) who
tells you they can predict with certainty what the effect of
purchasing higher octane fuel will have on any particular car's fuel
economy at any particular time or place is talking thru their hat.
There are just too many different factors beyond the scope of their
knowledge for such a statement to be anything but a guess.

-jim


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"Elmo P. Shagnasty" wrote:
>
> In article >, jim > wrote:
>
> > Anyone (including the car's manufacturer) who
> > tells you they can predict with certainty what the effect of
> > purchasing higher octane fuel will have on any particular car's fuel
> > economy at any particular time or place is talking thru their hat.
>
> yeah. Gee, you're right. Honda's engineers are pretty much stupid, and
> don't know anything.
>
No. If you had ask I would respond that Honda's engineers are among
the best. But as far as I know all that they say about mileage
estimates on their vehicles is something to this affect: "Your actual
mileage may vary".
It would be pretty pointless for the engineers to enter into a
technical dialog with customers about the numerous factors that
contribute to the wide range of mileage that their customers get from
the same make and model vehicle. I mean look at your response - it
appears the only thing technical that you were able to grasp and
respond to was the analogy I made between grades of beef and grades of
gasoline.

-jim


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C. E. White wrote:
>
> http://www.cartalk.com/content/featu...ium/myths.html
========

Ed, that Car Talk page is a great link. Thanks for providing it.
I'm copying part of it into the newsgroup for permanent
archiving.

CarTalk.com passage:

It's true that premium gas does contain special or extra detergents,
but in our opinion they're of no additional benefit.

Our advice is to ignore any sales pitch about the super-special
detergents that come in the premium-grade fuel.

These days, all of the gasoline from the major gas companies contain
more than enough detergents to keep your engine clean. Period.

The only reason you might have a use for the extra detergents in
premium,
is if you have a noticeably dirty engine, and need to scrub carbon and
other
crud off engine components. (And, if you're doing that, we'd instead
suggest
that you toss in one of the many fine engine additives.)

You said "major gas companies." Is there a difference in the gas
between
the big names, and the El-Cheapo gasoline at my local Costco or
Stupey-Mart?

There is. A number of years ago, some of the major auto manufacturers
were ticked off with the deposits from gas that met EPA detergent
standards. In other words, they were afraid they'd take the heat for
problems, when their customer's engines clogged up from the twigs
and dirt that was getting deposited on their fine handiwork.

So, they set their own guidelines, which they call "Tier 2." All of
the gas
from the major gas companies meets the Tier 2 standards. The gas at
your local Quickie Mart probably does not. The difference? In some
tests, after about 10,000 miles, there was a minor amount of crud
built
up on engine components that ran exclusively on Quickie-Mart gas.
Do we think this is an issue? Not really. But, would we advise
running
your car for 100,000 miles only on Quickie-Mart gas? Not if you're
concerned about the longevity of your vehicle. We recommend switching
back and forth between Tier 1 and Tier 2 — maybe every other
tank full — to keep your engine running clean.

The formerly named British Petroleum operates only Amoco and Arco in
the US. Not the top names or on the Tier 1 list. So I guess your shop
is probably right.

However, BP does have excellent lubrication products like Castrol oils
and the likes of GT Low Moisture Activity brake fluids. Maybe their
European gas is Tier 1 equivalent? Don't know.



On Jul 29, 9:59*am, "Elmo P. Shagnasty" >
wrote:
> That's hilarious, because the local lawnmower shop specifies NOT to use
> BP under any circumstances.
>
> This place has been around for 50 years, and they've said that for as
> long as I can remember.

"doug" ...
> After reviewing the list of TOP TIER Gasoline Retailers at their website,
> http://www.toptiergas.com/retailers.html , I couldn't help but notice that
> Valero, one of the largest independent refiners in the eastern US, was not
> on the list. Here in Delaware, the Valero refinery in Delaware City was
> built in the mid 1950's specifically designed to handle sour crude. It is
> still in operation, providing numerous retail operations in this region,
> including Shell (which IS on the list) with their gasoline.
>
> If suppliers like Turkey Hill Minit Markets and Qwik Trip are identified
> as being Top Tier gasolinr retailers, why isn't Valero? Especially if they
> are supplying gasoline to companies that ARE on the list?
>
It is all in the additive package added to the tanker truck
after/during/before the same base gas is transferred to the trick. Same
gas, different additives.

I, for one, am not convinced that this Top Tier stuff has any meaning at all
anyway.
Tomes