Tuesday, October 30, 2007

Halfway Through Tank - 30 October 2007

This morning I passed down through the halfway point of the tank, right
about 240 miles. While I like it to be at 250 miles, this was actually
encouraging, because yesterday on my way home I was at 218 and really
really close to the halfway point.

Most of my way home yesterday and half of the way here today I was able
to drive in the slipstream of a tractor trailer.

Don't go nuts about "that's crazy."

I am about 100-125 feet behind, and have a cleat view to the lanes on
either side of the truck and always check for brake lights in those
other lanes as an indication of potential slowing in my lane. I also
make sure that there's room on one side of me or the other to
immediately swerve out of the way in an emergency.

Oh, and rush hour traffic usually never tops 55 on my way home.

I am not a "bumper sticker," but a smart drafter. If the truck speeds
up faster than 65, I let it go, and if it drops slower than 50, I pass

Driving in general is a dangerous activity, and I am keenly aware of my
"out" in case of danger.

Here's to smart driving!

Wednesday, October 24, 2007

Tank 135 - 24 October 2007

Filled up this morning at the Fredericksburg Costco with 10.694 gallons
of gas. The loe fuel light came on three times on my way home
yesterday, and stayed on for good at 415.8 miles. I travelled 8.2 miles
more before filling up, making it 424.0 miles on this tank.

That made for a fuel economy of 39.65 mpg on this tank.

This is nice, because I was stuck in heavy traffic on a couple occasions
in this tank. The expected hit on my mileage was apparently offset by
my avoidance of using the air conditioning. It was warm in the last
several days, but not wuite hot enough to need the AC for very long.

I refueled on October 25 of 2006. Comparing data from these to days one
year apart, I see that I have driven farther this year, but spent less
money on gas, even though gas has averaged about 12 cents more per

My fuel economy for 2006 averaged 36.26 mpg, and so far in 2007 it has
been 37.87 mpg, about 4.4% higher.

My average fuel economy has increased during each year of ownership of
this car. I wonder how long this will last? Obviously the engine is
broken in, and I think my smart driving tactics are pretty well
developed. Perhaps I will break down and seek out "fuel saving motor
oil" for future oil changes, or synthetic oil to see how that works.

That reminds me, I still must check my tire air pressure to make sure
they're still pumped up to 40 PSI. Although my fuel economy has been
stable, which indicates my tires ought to be still pumped up, it's smart
to check that air pressure for safety reasons as well.

Friday, October 19, 2007

Tank Update - 19 October 2007

Very little news this week as I commute to and from work. I was able to
take the green minivan to work one day to get it inspected while I was
at work. Other than that, very little to post.

Sorry folks, but sometimes there's just no news.

Monday, October 15, 2007

Tank 134 - 15 October 2007

So this morning I had the opportunity to refuel at the Fredericksburg
Costco. Filled up with 11.112 gallons after going 423.7 miles, making
for an average fuel economy of 38.13 mpg for this tank.

The Low Fuel light came on for good at 408 miles.

This was the Mighty Corolla's 35th tank for the year. Last year's 35th
tank came much earlier, on September 26, 2006. Mileage for that tank
was 37.55 mpg.

After 35 tanks last year, I has spent $880.18 on gas. After 35 tanks
this year, it is 909.99. But if you go be calendar date, Overall gas
expense was $931.11 on October 17, 2006, and $909.99 on October 15,

Miles travelled is pretty close as well. On October 17, 2006, I had
gone 13,844.7 miles, and as of today in 2007, I have gone 13,837.2
miles. I will have gone more miles by the 17th of October, though.

For calendar year 2006, gasoline averaged $2.378 per gallon. This year,
it's averaged $2.492 so far, about 11.4 cants more per gallon. Gas did
go up in price over the last two months of 2006, however it was on a
down trend as 2005 closed out, so there is no pattern there. We shall
see how overall cost works out.

I predict 43 tanks of gas this year. Last year ended with 46.

Wednesday, October 10, 2007

Halfway Through Tank Update - 10 October 07

It has been uneventful commuting over the past days. Had a three-day
holiday weekend, and a short week this week as well. The needle dropped
past the halfway point of the gauge yesterday at about 258 miles, which
bodes well for overall fuel economy this tank.

It's probable that I will not have to refuel until Monday, October 15,
which will give me a fair number of days between tanks. I continue to
drive smartly on my commute, but also stay with the flow of traffic.

I have noticed that traffic in the mornings this week has been heavier
than normal, but as I try to keep going at 64-66 mph, I actually am
staying in the middle lane a bit more and actually am passing people
this week on the way to work.

That's kind of fun.

Friday, October 5, 2007

Gas Prices Change!

So I refueled on Tuesday morning at $2.549 per gallon.

Wednesday morning as I passed the same station (Woodbridge Costco), gas
was $2.499 per gallon. Yesterday I walked over to the Woodbridge Costco
for lunch, and gas was $2.429 per gallon.

If I got worse mileage, I'd be quite ticked!

Putting in 11 gallons, I conceivably would have spent $1.32 less on the
same amount of gas on Thursday than on Tuesday, about 5% less.

Of course, had I waited until Thursday, I'd have run out of gas, so it's
not like I really had a choice.

Drive smartly this weekend, folks!

Wednesday, October 3, 2007

New Statistics!

I have spent a few minutes thinking of other ways to create descriptive
and/or helpful statistics for me to use when analyzing my fuel
consumption and travel data.

A neat thing is that I can go back in time to make historical
information about these statistics, even though I just now thought of
them, to see how things have changed (or not) over the last years.

Popular stats include miles per gallon (mpg) and average mpg. That's
about it, I guess.

But today I started wondering how much this actually costs me as I
travel around. Obviously, highway travel at a constant speed will be
less than stop-and-go traffic driving, but aggregate numbers derived
from each tank ought to give me a good general idea.

Some media outlets use "cost per mile" as part of ownership costs. I
can figure out my gas cost per mile each tank. I change my own oil, and
have not had any major engine or brake work on the car yet, so that data
obviously would affect things. But overall cost per mile seems good.
Only thing is, the fluctuations of gas prices really change it a lot.

This year, I paid 7.3 cents per mile on a tank that served me with 37.6
mpg, yet 7.2 cents per mile on a tank that got me 39.42 miles per
gallon. One tank I paid 5.1 cents per mile but just got 36.6 mpg. This
may not be a good statistic.

Then I thought of "miles per dollar," which is almost as useless, but
easier for me to picture me spending money, as the numbers are bigger.
For instance, my last tank I went 430.8 miles, and spent $27.89 to
refuel, making for 15.45 miles driven per dollar spent at the pump. So
this is about $4.00 per hour driving at about 63 miles per hour.

I gladly entertain ideas for better descriptive statistics. For now I
can impress my friends and family (or bore them, if you feel that way)
by announcing that I spend about six and a half cents per mile in my

At the very least, I can be proud (to use the term generously) that I
probably am the only one in my circle of friends that knows this sort of
information about my primary vehicle.

Tank 133 - 3 October 2007

Again I filled up at the Woodbridge Costco this morning, making this the
third consecutive tank I have refilled at this location. 10.942 gallons
after going 430.8 miles = fuel economy of 39.37 mpg!

One year ago, my mileage was 36.33 mpg for the tank used at that time.

This was my 34th tank of 2007. My 34th tank of 2006 came on September
19. So I am refueling less frequently this year than last year. But I
have driven more miles: 13,413.5 miles on 34 tanks in 2007, 12,509.6
miles on 34 tanks in 2005.

Going by calendar day, Last October 5, I had gone 13,447 miles. I'll be
at 13,447 miles when I get home tonight, so I am about two days ahead of
schedule on the miles driven front.

One issue of mild concern (an issue I have only recently started
tracking, but was aware of about two years ago), is that when you total
up the miles driven for each individual tank, this number is WAY LESS
than the "hard wired odometer" reading.

Odometer reading at last fill-up: 49,028 miles

Total miles in 133 tanks: 48,977.6 miles

This is a difference of about 50 miles. I don't know where this
discrepancy came from. Even if each gas tank is off by two tenths of a
mile vs. the hard odometer reading, that only totals about 27 miles

This is odd.

Another problem is that a small plastic door has broken off my
dashboard. It's the cover for a small cubby that's big enough to hold a
pile of about 4 CDs. I rarely opened this little door, but in the last
two months, each hinge has failed at the pivot point. If I just remove
the cover, I can see around the gap of the outside of the cubby and it's
not that pretty.

Other than this small problem, the Mighty Corolla is doing fine.

Oh, and the steering wheel is showing signs of wear where my hands
usually rest on it.

Monday, October 1, 2007

Tank Update - 1 October

No major incidents since last update. Went 254 miles on the first half
tank, which bodes well for mileage.

Expect to refuel this week.