Fuel economy myths

"phil" <dbrider@cac.net> wrote in message news:47070B4A.44004113@cac.net...
> slowing down to 55 will do the most to conserve fuel
> i just read a study about mileage and cars,suv's are at the most
> efficient at 55mph regardless of what brand they are. between 30 mph and
> 50 the cars consume more as well as over 60 to 90 mph seems 55 is the
> sweet spot so it's no mistake that mileage is rated at that speed

I've found that to be true on my own cars that have the instant readout for
mileage. Repeated runs over the same piece of road at different speeds on
my way to work.

Problem is, you can't do it voluntarily by yourself. It is downright
dangerous to drive at 55 while everyone else is doing 70 or above. Nor can
I drive a car at 55 on the open road when both the car and highway are built
to sustain much higher speeds.

In article <470654ec$0$1614$9a6e19ea@unlimited.newshosting.co m>,
Brent <none@no.com> wrote:

> Wow, my Maxima easily sits 4 adults with lots of legroom. I can't put
> the seat all the way back and still be able to shift either. I have yet
> to find a GM that I could say that about.

In many cars of Japanese origin I need the drivers seat all the way
back, but then the steering wheel is too far away.
Unfortunately they are often set up for shorter drivers.
For example I can't comfortably drive the Toyota Corolla, the steering
wheel is too far away. The Chrysler '95 Cirrus had this same problem.
The previous Corolla model my knees hit the steering wheel, so I
couldn't brake with my foot flat on the pedal.

The Toyota Camry fits me, but I need the telescoping steering wheel all
the way back.
At least I don't hit my head on the ceiling as I did in a Honda Civic of
10 years back.
The Impalla fits me perfectly, as does my Concorde.
My height is only 5'-11"

In article <DsCdnfJ7s86a-JvanZ2dneKdnZydnZ2d@bt.com>,
Coyoteboy <coyoteboyuk@m> wrote:

> Chevy Man wrote:
> > Only thing I see that will force higher fuel economy is for gas to get up
> > to
> > around $10 a gallon. Most people have not even slowed down at $3.
>
> Wont affect anyone anyway - in the uk we pay the equiv of 7.70 a US
> gallon - people here are still happily ploughing around in 20mpg cars
> (me included).
The cars I see in the UK, I travel their every few years, are
significantly smaller on the average than those in NA, with smaller
engines.
In NA a mid sized car needs at least a 2.7L V6 engine to sell.

However in both the UK and NA there seems to be a trend for some people
to go larger and some to go smaller, so the number of fuel efficient
cars in the middle is decreasing.
Here in western Canada over 50% of vehicles are large truck based SUVs
or tall heavy cross over vehicles with large engines. Neither get good
urban mileage which is most of the driving.

"Edwin Pawlowski" <esp@snet.net> wrote in message
news:UeENi.367$LD2.225@newssvr17.news.. ..
>
> "phil" <dbrider@cac.net> wrote in message
> news:47070B4A.44004113@cac.net...
>> slowing down to 55 will do the most to conserve fuel
>> i just read a study about mileage and cars,suv's are at the most
>> efficient at 55mph regardless of what brand they are. between 30 mph and
>> 50 the cars consume more as well as over 60 to 90 mph seems 55 is the
>> sweet spot so it's no mistake that mileage is rated at that speed
>
> I've found that to be true on my own cars that have the instant readout
> for mileage. Repeated runs over the same piece of road at different
> speeds on my way to work.
>
> Problem is, you can't do it voluntarily by yourself. It is downright
> dangerous to drive at 55 while everyone else is doing 70 or above. Nor
> can I drive a car at 55 on the open road when both the car and highway are
> built to sustain much higher speeds.
>

I've found it to be true in real life measurements, but only in the
strictest definition of the word true. In all of my vehicles, the age old
adages about easy starts, easy stops, etc. have certainly been born out, but
the difference in the fuel mileage between driving at 70 instead of 55, or
jumping on it a little bit instead of grandfathering it off the line, was
inconsequential. In order to really impact mileage I find that I have to
put my foot into it completely, all the while - through the entire tank of
gas. Not at all practical for most driving. Otherwise, the difference in
mileage over a thankful is just not that significant.

--

-Mike-
mmarlowREMOVE@alltel.net

"Mike Marlow" <mmarlowREMOVE@alltel.net> wrote in message
> I've found it to be true in real life measurements, but only in the
> strictest definition of the word true. In all of my vehicles, the age old
> adages about easy starts, easy stops, etc. have certainly been born out,
> but the difference in the fuel mileage between driving at 70 instead of
> 55, or jumping on it a little bit instead of grandfathering it off the
> line, was inconsequential. In order to really impact mileage I find that
> I have to put my foot into it completely, all the while - through the
> entire tank of gas. Not at all practical for most driving. Otherwise,
> the difference in mileage over a thankful is just not that significant.

Since I don't drive at 55 I cannot factor that into my daily life. I can,
however, compare the grandfatherly driving versus putting the foot into it
once in a while, using my remote starter to hear up the car when cold or
start the AC when very hot. While I don't "speed", I often do like to
accelerate up the entrance ramp to the highway and be doing 70 at the top.
The difference between the two types of driving cost me about 38 gallons a
year over 23000 miles.

I can hear some of you saying "not big deal, enjoy driving" while others are
screaming that "a family in Ethiopia can plow their fields with what you
wasted". Judge as you please but I'm not going to change. Another zinger,
my total cash outlay for gas last year was probably $200.

phil wrote:

> slowing down to 55 will do the most to conserve fuel
> i just read a study about mileage and cars,suv's are at the most
> efficient at 55mph regardless of what brand they are. between 30 mph and
> 50 the cars consume more as well as over 60 to 90 mph seems 55 is the
> sweet spot so it's no mistake that mileage is rated at that speed...

Which is the cause and which is the effect? Are official mileage
figures done at 55 mph because that is a fixed law of physics that that
is the optimum (fuel mileage) speed for a wheeled vehicle. *OR* is 55
mph optimized by the manufacturers for fuel mileage because that is the
speed at which the law arbitrarily says they have to be measuered at?

I know all about the square laws of wind resistance and all that, but I
have a hard time believing that 55 mph is the optimum speed by a fixed
law of physics and not an arbitrary design parameter. Things like this
get ingrained in the culture to the point that it starts being treated
as if it were a fixed natural law instead of some arbitrary phenomenon
created by legislation.

I submit that if the mileage measurements were required to be done at,
say, 65 mph, lo and behold, within two vehicle design generations you'd
find studies that proved that 65 mph was the magical optimum fuel
mileage speed. I'm not saying let's change the official measurement
speed to 65 mph, but let's be careful to not make the "55 mph is the
optimum fuel economy speed" an irrefutable law of physics.

Question: Would a study of all cars designed for use on the Autobahn
also show that opitimum fuel mileage speed is 55 mph?

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

"Bill Putney" <bptn@kinez.net> wrote in message
> I know all about the square laws of wind resistance and all that, but I
> have a hard time believing that 55 mph is the optimum speed by a fixed law
> of physics and not an arbitrary design parameter. Things like this get
> ingrained in the culture to the point that it starts being treated as if
> it were a fixed natural law instead of some arbitrary phenomenon created
> by legislation.

I don't know enough to dispute or confirm that.

When I was buying a Mack truck years ago, the salesman had figures on power
needed for various loads. At 60 mph, you needed more power to overcome wind
resistance than for rolling resistance or load. It would take some analysis
by an engineer to determine the if the 55 sweet spot is true or not. In the
case of final drive ratio, there has to be some compromise between highway
driving versus rural driving. City driving ratio selection is easily done
with the transmission lower gears. My 5 speed does not shift to the highest
gear until 40. Maybe a 6 or more speed would shift at 50 or higher to gain
better ratios at 70.

My guess is that gearing can be better optimized at various speeds, but at
some cost.

"Edwin Pawlowski" wrote:

I can compare the grandfatherly driving versus putting the foot
into it once in a while. The difference between the two types
of driving costs me about 38 gallons a year over 23000 miles.
Another zinger, my total outlay for gas last year was about $200.
__________________________________________________ ____

At $3 a gallon, $200 will buy 66.67 gallons of gas. And 66.67
gallons to go 23,000 miles means the car is getting 344.98 mpg.

Driving more conservatively will save the lost 38 gallons, using
only 66.67-38 = 28.67 gallons. This will result in a gas mileage
of 23,000/28.67 = 802.23 mpg.

That's what I call good gas mileage. Congratulations.

Rodan.

"Rodan" <Rodan@verizon.NOT> wrote in message
news:u8RNi.3895$9r2.3139@trndny04...
> "Edwin Pawlowski" wrote:
>
> I can compare the grandfatherly driving versus putting the foot
> into it once in a while. The difference between the two types
> of driving costs me about 38 gallons a year over 23000 miles.
> Another zinger, my total outlay for gas last year was about $200.
> __________________________________________________ ____
>
> At $3 a gallon, $200 will buy 66.67 gallons of gas. And 66.67
> gallons to go 23,000 miles means the car is getting 344.98 mpg.
>
> Driving more conservatively will save the lost 38 gallons, using
> only 66.67-38 = 28.67 gallons. This will result in a gas mileage
> of 23,000/28.67 = 802.23 mpg.
>
> That's what I call good gas mileage. Congratulations.

I said that was MY total cash outlay. I do buy gas once or twice a week.

<clare at snyder.on.ca> wrote in message
news:v9lfg3dm04c7rbsmjqo90taa5sr8akd7ap@...

>
> Gas here regularly drops from about $ 1.14 per liter to $.94, and
> occaisionally (but not lately) $.87.
>
> When the reserves gut too high, the price drops. For any excuse at
> all, it goes up.

Correct - but it's hovering around a consistent price. That's not a plummet
as the OP stated.

--

-Mike-
mmarlowREMOVE@alltel.net