Hi all. There was an earlier thread on this but it seemed to peter out so I thought I'd start fresh.
When I use a certain store's gasoline, which is from a local supplier and is kind of a "mom and pop" gas station, my mileage goes through the roof. I consistently get 34.5 and higher; last tank was 36.5. The tank I am on now, which is gas from a large national chain, is miserable. I'm down around 32.5 MPG. The odd thing is the weather's been nicer so I've been using the AC less but also keeping the windows mostly up. I've found that BP, which is recommended by Ford, is kind of middle of the road. Unfortunately, I live in a state where free enterprise is frowned upon, so I don't have access to Sinclair, Exxon, Chevron, or pretty much any brand on one of the coasts. Has anybody else found that smaller chains are better?

The smaller chains usually are getting thier gas from one of the big guys as they don't have there own refineries. It appears your getting a good blend and it may be from one of the other refiners that is not operational in your area. I notice the same thing here and used to get great mileage with Shell till they pulled out of our area.

2005 Prius - White, Gray Interior, Option Package 6, Mud Flaps & Auto Door locks from Coastal


2006 Highlander Hybrid - Limited, White, Tan Interior, Nav, 4WD, Trailer Hitch

NOTE: On both the Prius and HH batteries are included with your purchase !

From your experience it would be my guess your
station is being supplied by one of the Top Tier
Gasoline suppliers

For more information you can got to...

www.toptiergas.com

and for a list of retailers of top tier gasoline.

I believe in it myself and burn QuickTrip
in my Prius 100% of the time. FYI - I live
in the Dallas area and Quick Trip is suppled
from either a refinery in Tulsa (Sunoco I think)
or Conoco-Phillips in Bartlesville, OK.

Alden Bowles
2005 Toyota Prius II HSD

Abowels: It's at least as likely your gas is coming from Flint Hills Resources's refinery in Corpus Christi.

There are about 140 refineries in this country. Of these, about 110 refine gasoline (as opposed to asphalt, or other different petroleum products).

Out of those 110 refineries comes the gasoline for 270 million Americans.

I'm skeptical about "top tier" anything. In light of exchange agreements, etc.,. most gasoline in a given area comes from the same very small handful of refineries.

The only difference in gasolines is the detergent type additives majors add (think techron). I doubt detergents would cause a reduction in gasoline, but maybe.

More likely, the change is due to seasonal differences in gasoline formulations, not necessarily from different refineries who all make a fungible gasoline to specific specifications.

The last time I read anything about this, Hess was suppose to be one of the tops, especially for premium grade.

However, the sign outside of a station no longer needs to match was is in the underground tanks. The sign outside might say "Sunoco", but their regular gas could be from a Citgo truck.

Best single LD trip: 35.3mpg

Sorry Stevejust, but its not likely at all since
I spoke with a tanker driver at my QT here in
Plano. He specifically stated he was coming
from Oklahoma and I am thinking he said
Tulsa but can't remember that part for sure.
That makes perfect sense since QT HQ is in
Tulsa. It would not be required for them to
have a local fuel deal but it does make sense
since they were limited to Oklahoma for quite
a while before expanding.

As far as scepticism, I really am with you
generally. On this topic I have nothing to offer
in the way proof except my own personal
anecdotal evidence of slight but noticeable mpg
improvement.

As far as the fungible nature of gasoline I agree
to the point where the individual retailers take
delivery.

Alden Bowles
2005 Toyota Prius II HSD

There is spot market gas and top tier gas. Spot market is what grocery stores and other non branded fuel sell. This is sold on BTU content and generally has a lower BTU content therefore lower fuel economy. This fuel also has inferior additives so induction systems get clogged and deposits will form faster on valves and fuel injectors. Top tier gas usually has a higher BTU and much better additives. The additives will differ from brand to brand and are or can be added at the terminal. That does not mean that the fuels are the same. They have a pneumatic ball that will separate the fuel as it travels down the pipeline to the terminal. So Exxon, Shell and others may use the same terminal but that does not mean they are the same fuel. Also in certain markets the EPA has mandated oxygenated fuels in certain non attainment areas. These fuels typically have 10% alcohol and some special additives so on paper they are environmentally friendly. In-fact they have lower BTU so any gains are wiped out in higher fuel consumption.

Ducit Amour Hybridae
Mark Smith
Master Certifited Technician
Tempus non reparabilis fugit
"It isn't pollution that's harming the environment. It's the impurities in our air and water that are doing it."

Best Tank 35.0 MPG

This makes sense and explains why Exxon, Chevron and Shell 87 all tested high energy.

What about dissolved butane? I understand the winter blends often have butane dissolved in them but it wasn't clear if this happens at the refinery or further down the chain.

Thanks,
Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Gas is refined for different weather conditions. In cold weather you need a fuel that has a lower vapor point, this allows engines to perform and start in cold weather while keeping the fuel atomized. In the summer fuel is refined for higher vapor point (reed vapor pressure). This keeps the fuel from vaporizing to soon i.e in your gas tank. Also helps with vapor lock in ICEs. As to how they do this I dont know for sure but allowing some lighter hydrocarbons is probably the case. This does not include the oxygenated fuels which also are blended for winter and summer. There are also several specs on the oxygenated fuels so the refiners are in a real pickle when the y do a change over. Thats why they claim gas shortages in the spring and fall. I think I read there are 28 different blends they are required to make to cover the USA.

Ducit Amour Hybridae
Mark Smith
Master Certifited Technician
Tempus non reparabilis fugit
"It isn't pollution that's harming the environment. It's the impurities in our air and water that are doing it."

Best Tank 35.0 MPG

OK, so I've been getting pretty consistently 6.4-6.5 l/100Km with my TCH lately. It doesn't seem to matter a whole lot how I drive it - at least not in any kind of a consistently measurable way. I try like crazy to follow the various recommendations I've been reading about. For the last two tanks, I've increased my tire pressure from the recommended (I think) 34 psi to 40 PSI, with no noticable difference. I've paid careful attention to my driving practices, but still no significant gains. Also, two tanks ago I had my first oil change at 8000 Km and used 0W20 synthetic - did I mention no noticable difference? I've also consistently used absolutely nothing but Esso for gas, from day one.

Today, I filled up with Petro-Canada, one of the listed top-tier retailers. So, if there is any significant difference, hopefully I'll see it pretty soon. By the way, I ran the tank as close to empty as I dare, filling up with 64.8 liters (out of a listed maximum of 65), for those of you concerned with dilution and mixing of brands. Wish me luck.

--My hybrid came home!--
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Randy