Gas mileage

Posted by Edwin Pawlowski on October 3, 2005, 8:48 pm

In a recent thread we had comments about fuel mileage, SUV's etc. I did
some research using my full sized car and the instant read mpg on the
computer that it has. I took readings on the same places, seemingly very
level. Keep in mind the gauge read whole numbers so decimals are not show
but may be rounded.

Using cruise control to keep the human element out, I drove at 70 mph, 65
mph, 60 mph. There was no shown difference between 65 and 70. When I made
the run again at 60, is showed a 3 mpg increase.

I drive about 12,000 mile a year on highway (total is about twice that).
Saving the 3 mpg saves a total of 52 gallons of gas. At today's price of
$3, my savings per year is $156.

Now, driving at 70 mph, I will spend 171 hours at the wheel. Driving that
same distance at 60 mph, I'll be spending 200 hours for the same trips. So,
to save $156 I have to give up 29 hours of my free time. The actual mpg
will vary on different cars, but that is what I was able to do with a Buick
LeSabre. I also don't notice any difference with the AC on or off so I go
for comfort. YM WILL V
Ed

Posted by Rich256 on October 3, 2005, 9:28 pm

> In a recent thread we had comments about fuel mileage, SUV's etc. I did
> some research using my full sized car and the instant read mpg on the
> computer that it has. I took readings on the same places, seemingly very
> level. Keep in mind the gauge read whole numbers so decimals are not show
> but may be rounded.
> Using cruise control to keep the human element out, I drove at 70 mph, 65
> mph, 60 mph. There was no shown difference between 65 and 70. When I

made

> the run again at 60, is showed a 3 mpg increase.
> I drive about 12,000 mile a year on highway (total is about twice that).
> Saving the 3 mpg saves a total of 52 gallons of gas. At today's price of
> $3, my savings per year is $156.
> Now, driving at 70 mph, I will spend 171 hours at the wheel. Driving that
> same distance at 60 mph, I'll be spending 200 hours for the same trips.

So,

> to save $156 I have to give up 29 hours of my free time. The actual mpg
> will vary on different cars, but that is what I was able to do with a

Buick

> LeSabre. I also don't notice any difference with the AC on or off so I go
> for comfort. YM WILL V
> Ed

Or you can say you are paying about $5.50 an hour to drive 70 instead of 60
( or earning $5.50, tax free, driving at 60).

The "Myth Busters" did a segment on driving with AC or windows open. It was
not very conclusive I thought. I think the windows open won but the guy
with the AC on was freezing. They were not diving at 70 mph either.

Posted by Edwin Pawlowski on October 3, 2005, 9:54 pm

> Or you can say you are paying about $5.50 an hour to drive 70 instead of
> 60
> ( or earning $5.50, tax free, driving at 60).

That is for the saved 29 hours. For the full time it is more like 91¢ per
hour.

> The "Myth Busters" did a segment on driving with AC or windows open. It
> was
> not very conclusive I thought. I think the windows open won but the guy
> with the AC on was freezing. They were not diving at 70 mph either.

I think speed and car design would make a difference. On a smaller engine,
the AC would take more power as a percentage than a larger engine. Years
ago, I'd shut the AC off to pass another car or to struggle up a hill. On my
car, I cannot feel any difference. Compressors have improved.

Posted by Duane Bozarth on October 3, 2005, 7:10 pm

Edwin Pawlowski wrote:

> > Or you can say you are paying about $5.50 an hour to drive 70 instead of
> > 60
> > ( or earning $5.50, tax free, driving at 60).

>
> That is for the saved 29 hours. For the full time it is more like 91¢ per
> hour.
>

> > The "Myth Busters" did a segment on driving with AC or windows open. It
> > was
> > not very conclusive I thought. I think the windows open won but the guy
> > with the AC on was freezing. They were not diving at 70 mph either.

>
> I think speed and car design would make a difference. On a smaller engine,
> the AC would take more power as a percentage than a larger engine. Years
> ago, I'd shut the AC off to pass another car or to struggle up a hill. On my
> car, I cannot feel any difference. Compressors have improved.

There's also a good probablility the computer cuts the compressor off
when you downshift automagically, too...

Re: your "test"--I wouldn't put too much faith in the absolute values of
those onboard systems for small differences and short distances
particularly. Your data doesn't negate physical reality other than the
zero difference at the lower speed differential which is quite likely
owing to the imprecision of the display as much as anything (as you
note)....

Posted by Rich256 on October 3, 2005, 10:38 pm

> > Or you can say you are paying about $5.50 an hour to drive 70 instead of
> > 60
> > ( or earning $5.50, tax free, driving at 60).

> That is for the saved 29 hours. For the full time it is more like 91¢ per
> hour.

I look at is as your driving 70 instead of 60 you saves about 10 minutes.
The 91 cents is the savings for the 10 minutes, not the whole hour.
Therefore the $5.40 an hour for the saved time.

Page 1 of 7 1 2 3 > last >>

Similar Threads	Posted
Track your mileage and gas consumption	May 14, 2008, 11:09 am