Just an observation. When I use gasolines listed as being 'Top Tier' gas,
the mileage goes DOWN in my Supra, Scion tC and a Chrysler LHS I had a
I usually use Gulf oil ,since they are local and usually less $$$ than the
others in my area. I have always gotten decent MPG with Gulf.
The last two fill ups I did were with Citgo (Yeah, Hugo...) and the
mileage I just calculated from the Scion was 33.56 MPG, the best I have
With Shell, my MPG usually goes *DOWN* one or two MPG...
If you are just caluclating single tank averages, I suspect you results are
not meaningful. I doubt if the feed stock to the Citgo, Shell, and Gulf
sations are actually coming from individual Citgo, Shell, and Gulf
refineries. It may be that one or the other uses ethanol, while the other
does not. I've never really been able to detect any consistent difference in
fuel economy based on brand. In I have bought gas from certain stations on a
regular basis, and then becasue of a change in pricing or credit card
rebates, switched to another brand. Looking over the data shows little
consistent difference between brands, I can show a definite variation based
on the month. And interestingly, the worst months are in the spring. My best
gas mileage is in the summer months. This may be related to changes in
formulation related to the season.
Gulf has an interesting map on their web site that shows thre distribution
network and whether they are selling "Gulf" gas or gas from another
supplier. They have four categories - Proprietary, Purchase, Exchange, and
Throughput. I am guessing these mean - Proprietary: gas that meets some
"special" Gulf standards and is delivered directly by Gulf; Purchase: gas
purchased for cash from another supplier as is, but sold as Gulf; Exchange:
gas aquired from another supplier by exchaning production as is but sold as
Gulf; and Throughput: Gulf gas moved through another system (see
http://www.gulfoil.com/distribution.asp ). Since Gulf does not actually own
a refinery, they are not really selling "Gulf" gas, but I suppose the
"proprietary" Gulf gas has Gulf's own particular combination of additives.
The Wikipedia article on Gulf in interesting
(http://en.wikipedia.org/wiki/Gulf_Oil ). It turns out that Chevron actually
owns the "Gulf" trademark, but that in the US "Gulf" gasoline is sold by a
non-US company operating as Gulf Oil L.P. It is just a marketing outfit, so
I see no way you could expect their gas to be "special," at least
My understanding is the top tier gas just refers to additives which may help
keep the engine cleaner. There would be no impact on mpg which would
probably be most affected by ethanol content as you mentioned.
Other than the impact of a clean fuel and combustion system vs. a dirty
fuel and combustion system.
Dirty injectors, dirty valves, etc--all that will cause lower mileage.
Keep everything clean, get better mileage.
On Fri, 01 Aug 2008 07:00:55 -0400, "Elmo P. Shagnasty"
Anybody know how additives are put in the truck tankers?
A fellow in another group says a number of gas companies
all get their gas from the same Hess depot near his home, all the gas
coming through the same pipeline from the same ship.
Says it's all the same gas going to Texaco, Chevron, etc, and
the additive claims are BS.
The only answer I can think of is they put the additives in at the
Hess depot, but I don't know.
In most places all the gas stations in that locale get their gas from the same
terminal. Additives are added when the tanker trucks that deliver to the retail
stations are filled.
Here is an article that describes the process
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That one refinery may create the base gasoline that's used for many
brands, that refinery offers its customers a Chinese menu of choices for
filtering and anti-contamination, as well as additives.
To say "it all came from the same refinery, therefore it's all the same
gas" is like hearing my chemistry-challenged father exclaim "it's just
salt!" when someone told him that making aspirin involves "salt of
With the state of American Industry today, I would be surprised if the
different brands still customize their additive packages. In my part
of Ohio, gas stations buy their gas from either Sunoco or BP's
refinery. I would guess that Sunoco blends their gas for their
stations and anyone buying gas from their refinery is really getting
Sunoco gas. I do know that only one firm hauls gas from both
refineries. So if the refinery still sells a base stock and each
brand then adds it's own additives, someone has to stock those
additives. Either the refinery, the trucking firm or the gas station
would stock them and I can't see Sunoco stocking additives for Gulf or
On Fri, 01 Aug 2008 16:12:42 -0400, Retired VIP wrote:
Several oil companies still advertise a custom additive package, so
they would have to do it everywhere to not get nailed by the Gov't.
The pipeline company owned tank farm that all the delivery tank
trucks in the region fill from would stock the various 'special'
detergent packages and meter them into the pipeline commodity raw
gasoline as the trucks were filled from the metering racks.
If the gas is going to an independent gas station or a corporate/
government private fueling station, they just put in a generic package
that meets the federal minimums - unless the customer pays extra for a
double dose or something better...
The detergent is probably shipped in by the 55-gallon drum or the
300-gallon or 600-gallon UN Cube style tank, ultra concentrated. An
educated guess says they only need a pint to quart of detergent to
treat a full 8,000 gallon tank-truck load, so one trailer load of
detergent would go a long way.
--<< Bruce >>--
You are very hard-pressed to measure to the nearest tenth of an mpg.
You will not be able to measure to a /hundredth/ of an mpg unless maybe
your tire radius varies no more than say a thousandth of an inch, for
Be satisfied if you can measure to the nearest whole mpg. Plenty of
people will tell you that EPA can't even do that.
Let alone hundredth. 33.56? That's a bogus and meaningless number.
Unless he starts with a steam-cleaned and empty tank, and does nothing
but fill it from known cans with known quantities of fuel in it, he's
lucky to know within one or two mpg what the real number is.
It's important to know when you normally hover around 33mpg that all of
a sudden you're hovering around 28mpg, but moving around anywhere from
32 to 34, centering around 33 on a regular basis? That's temperature,
tire pressure, tire wear, and gas pump shutoff valve variability
talking. Nothing in the engine has necessarily changed.
Your engine needs some work. I always get from 33.62 to 33.68. It once
dropped to 33.34, but I took it to the dealer for a tune-up, new plugs,
filters, the works, and it immediately went up to 33.65. It was $550 well
Edwin Pawlowski wrote: (Re 33.56 MPG Scion)
Your engine needs some work. I always get from 33.62 to 33.68.
It once dropped to 33.34, but I took it to the dealer for a tune-up,
new plugs, filters, the works, and it immediately went up to 33.65.
It was $550 well spent!
Edwin has a way of driving a good bargain. Most would have paid much more,
but he's cheap and he won't shell out a nickel more than he absolutely has
to. What a shame to, when as you can see, he clearly go way more than $550
worth of value out of this deal.
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