Quality of Gasoline

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Trey - 25 May 2004 09:20 GMT

I was talking with a friend and she said "why pay ten cents a gallon more
for chevron gas, when ABC Gas is just as good?"

So lets start the debate, what makes one station cost more, besides the name
on the sign.
Chevron really better then Arco? why? what is in the fuels that make them
different?

I know there are items like ethanol, MTBE and sulfur (just from memory) what
other chemicals are used like these?

My truck manual pretty much just says to stay away from MMT and sulfur as
best you can.

For my motorcycle, the manual says,
"Gas containing MTBE:
Unleaded gasoline containing MTBE may be used in your motorcycle if the MTBE
content is not greater than 15%"

"Gas/Ethanol blends:
Blends of unleaded gasoline and ethanol also known as GASOHOL, may be used
in your vehicle if the ethanol content is not greater than 10%"

"Gas/Methanol blends:
Fuels containing 5% or less methanol may be suitable for use in your
motorcycle if they contain co-solvents and corrosion inhibitors"

So who makes the best gas? and is it worth what they are charging over the
other companies?

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fbloogyudsr - 25 May 2004 16:05 GMT

> I was talking with a friend and she said "why pay ten cents a gallon more
> for chevron gas, when ABC Gas is just as good?"
[quoted text clipped - 3 lines]
> Chevron really better then Arco? why? what is in the fuels that make them
> different?

There are two refineries in the Seattle area; they use the same crude
(Alaskan),
and provide all the raw gasoline for Shell, Union 76, Arco, Costco, Safeway,
Tesoro, etc. It *IS* the same gas, exclusive of additives.

> I know there are items like ethanol, MTBE and sulfur (just from memory) what
> other chemicals are used like these?
> My truck manual pretty much just says to stay away from MMT and sulfur as
> best you can.

The basic raw formulation is mandated by EPA. You can forget about
everything but ethanol and additives like Techroline.

Arco stations (in WA at least they used to) use 10% ethanol IIRC -
there is some sort of tax break. All the other additives are added by
the distributor. AFAIK, no distributor (in the US) adds methanol.

FloydR

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Bob Kegel - 25 May 2004 19:43 GMT

> There are two refineries in the Seattle area; they use the same crude
> (Alaskan),
> and provide all the raw gasoline for Shell, Union 76, Arco, Costco, Safeway,
> Tesoro, etc. It *IS* the same gas, exclusive of additives.

Actually there are five working refineries in Western Washington, all within
a couple hours of Seattle.
See http://www.ecy.wa.gov/programs/swfa/industrial/oil1.html . I buy my gas
at a Safeway. The guy who drives the tanker truck says it comes from US Oil
& Refining in Tacoma. Told me it runs 2-3 octane points higher than the
minimum for the grade. YMMV

Gas is gas. Any differences are probably regional and due to different crude
sources and refinery equipment.

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Dori A Schmetterling - 26 May 2004 17:19 GMT

On neither this nor the Merc NG have I seen Europeans discussing the merits
of different sources of petrol/gasoline.

Is there something about North American petrol that prompts repeated
queries/discussions? There also seem to be a lot of US/Canadian people
trying to use a lower octane number than recommended by the mfg, and a lot
wondering about using a higher number than recommended.

DAS
Puzzled Brit

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---

> > There are two refineries in the Seattle area; they use the same crude
> > (Alaskan),
[quoted text clipped - 11 lines]
> Gas is gas. Any differences are probably regional and due to different crude
> sources and refinery equipment.

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fbloogyudsr - 26 May 2004 20:53 GMT

> On neither this nor the Merc NG have I seen Europeans discussing the merits
> of different sources of petrol/gasoline.
[quoted text clipped - 3 lines]
> trying to use a lower octane number than recommended by the mfg, and a lot
> wondering about using a higher number than recommended.

It's all an "old wives' tale":
1) "Higher grades of gas have better additives and hence keep your
car running better". Used to be true (30 years ago), but is *FALSE*.
2) "Higher grades of gas give you better mileage." False, except for
newer engines with knock sensors.
3) "My car ran crappy after getting *** brand of gas from &&&
gas station. Must have had water or dirt in the tank." False, because
virtually all tanks are now hermetically sealed (vapor recovery.)
Also false because people just don't change their fuel filters often
enough, or because a mechanic says he can't find anything wrong;
"must be bad gas".

Floyd

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Raybender - 26 May 2004 21:25 GMT

> On neither this nor the Merc NG have I seen Europeans discussing the merits
> of different sources of petrol/gasoline.
[quoted text clipped - 7 lines]
> Puzzled Brit
> --

Dori,

I*think* your gas in Europe is generally better quality than we have here in
many parts of the U.S. Here in CA the regulations and multitude of "boutique
blends" make the gas both expensive (in *our* terms) and often just *barely*
meeting the octane requirements. As I noted in my post above, the constantly
shifting seasonal blends produce noticeable performance variations in my cars.

In many of the mountain states where the *old carburated* cars could run with
reduced octane due to the high altitude, the octane number for *each grade* of
gasoline was usually reduced by 2 points or so from the sealevel value. Now,
when modern fuel injected cars with Mass Airflow sensors automatically correct
for this effect, thus needing the correct octane value even at high altitude, *I
don't think* this practice has stopped. Maybe someone from CO could comment
here. Last time I was in CO was about 4 years ago, and I think the octane
values were still reduced at that time.

What's it like in Europe? If you go up in the Alps can you still get 95
research octane gas, or do they reduce the octane value and say "you don't need
it at this altitude"?

Frank

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Dori A Schmetterling - 28 May 2004 23:29 GMT

From your comments your question at the end also occurred to me. Austria
and and Switzerland might be good examples of where to check for varying
octane numbers. I have no idea.

Where I normally drive around in my own car in western Europe (GB, NL, DE,
FR, BE typically) I get standard 95 octane. There is a euro norm but, I
gather, this only lays down a bare minimum quality.

I have also rented in various central European countries, e.g. Hungary &
Slovenia, and don't recollect any issues. Whether their 95 octane fuel is
any different I don't know. The suppliers are often the same, i.e. Esso
(Exxon), Shell & BP or a state-owned company.

(95 as approx equivalent to 90/91 US.)

In GB most petrol stations also sell 97 or 98 octane, depensing on brand. I
think, e.g. Shell offers 98 whereas BP 'only' 97.

In summer I am planning to go to northern Italy and may go into the Alps.
If I remember I'll have a look at the petrol on sale.

DAS

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For direct contact replace nospam with schmetterling
---

> > On neither this nor the Merc NG have I seen Europeans discussing the merits
> > of different sources of petrol/gasoline.
[quoted text clipped - 30 lines]
>
> Frank

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Raybender - 25 May 2004 20:36 GMT

> I was talking with a friend and she said "why pay ten cents a gallon more
> for chevron gas, when ABC Gas is just as good?"
[quoted text clipped - 25 lines]
> So who makes the best gas? and is it worth what they are charging over the
> other companies?

Well, quite certain that I'm in the minority - perhaps a very small minority -
that seems to notice a difference between brands. I *know* all the gas comes
from the same refinery/pipeline and supposedly the only difference is the
detergent, and anti-deposit additives in the different brands. Also, I
*believe* that the EPA now mandates that all gasolines must pass the BMW
unlimited mileage test for valve deposits, but.....

Here in Northern CA we have a very hot, and very *dry* summer climate -
absolutely ideal for causing pinging if you are missing even 1 octane point.
Just go out and try climbing I-80 over the Sierras on a 110 degree afternoon
with 10% humidity - now that's a test of gasoline quality. Really hit my
Pathfinder hard one day, even though it has a knock sensor. Switched to Chevron
and then it was ok.

Anyway, I *do* notice a difference between brands, and between our summer and
winter blends here. CA recently mandated that all gasolines must now use
ethanol rather than MTBE as the oxygenate. However, for the year or so previous
to this mandate, Union 76 had big signs at all their stations saying they had
ethanol rather than MTBE already in their gas - it definitely ran better in both
my BMW and Pathfinder than other brands.

At the moment, I'm back to Chevron. Seems their summer blend, apparently with
ethanol now, runs just great - so I dunno. Even though all the *raw* gas comes
from the same pipeline, I wouldn't be surprised if some of the different
additive packages between brands contain various aromatic hydrocarbons that can
change what is known as octane sensitivity - which is a larger difference
between the motor octane and research octane numbers.

Frank

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