Gas Mileage AGAIN and the effect of speed

[Cape Cod Fleetwood]

When I first ventured onto the US road system in 2002, I was flabbergasted at the speeds that everyone was driving at, and soon realised that if I didn't keep up, I would be a statistic pretty quickly.

Try driving at those speeds down here, and your car would soon be clamped, for 28 days and receive heavy fines, including loss of demerit points against your licence.

Bruce.

Bruce you've never driven on the Autobahn I guess. I had rented a new Beemer, lost my nerve at 100mph and stayed to the right. People were running up my a$$, passing me and giving me the finger. Just move to America will ya? Ship your cars over. You can get parts cheaper and quicker, own guns (depending on the state you choose), and drive fast. God Bless America!

\m/
Laurie

[z3skybolt]

The speed limit between Austin and San Antonio TX is 85.  You can drive 95 all day long and no one will blink an eye.  We travel a lot in the western U.S.  Parts of Utah, Nevada, Montana, Wyoming....have very little traffic and virtually zero Highway Patrol.  Even the Cattle Hauler Semis run 90 to 100 mph.

But nothing like driving the autobahn in your rented BMW.... showing a(rental car) computer limited speed of 200 kmh(124.27 mph) and having Mercedes and Audi ...headlights flashing....blow by you at 150 mph plus!


Love it!

Bob

[Scot Minesinger]

At GN2018 in TX, I drove with traffic when the speed limit on the highway was 75mph, and 90mph was about right.  I rented a BMW 430i retractable metal hardtop convertible - what a blast!  Never drove it with the top up the entire time and blew past the cops on the side of the road at 90mph - they must pull over speeders past 100 mph in TX. 

BTW no idea bout what kind of mileage I was getting. 

[Jason Edge]

There were several mentions about the accuracy of speedometers and thought I would share another way to check accuracy.  If you do any traveling for straight distances on interstates (or other roads) with mile markers, you can use the odometer to gauge accuracy. Simply, note the odometer and a mile marker, and drive for 100 miles per the mile marker and look at your odometer. If it says 95 miles or 105 miles you know your speedometer is 5% under or over.  You don't have to drive 100 miles, but makes for easy math.  I've use this method several times on cars and trucks to determine change in speedometer accuracy where I slightly altered the tire diameter.

[Cape Cod Fleetwood]

But nothing like driving the autobahn in your rented BMW.... showing a(rental car) computer limited speed of 200 kmh(124.27 mph) and having Mercedes and Audi ...headlights flashing....blow by you at 150 mph plus!
Love it!
Bob

Oh those people are f'ing nuts. Oddly enough, very few crashes. Prolly because they're all driving real cars and are used to the road and speed.

\m/
Laurie

[35-709]

There were several mentions about the accuracy of speedometers and thought I would share another way to check accuracy.  If you do any traveling for straight distances on interstates (or other roads) with mile markers, you can use the odometer to gauge accuracy. Simply, note the odometer and a mile marker, and drive for 100 miles per the mile marker and look at your odometer. If it says 95 miles or 105 miles you know your speedometer is 5% under or over.  You don't have to drive 100 miles, but makes for easy math.  I've use this method several times on cars and trucks to determine change in speedometer accuracy where I slightly altered the tire diameter.

The speedometer needle is controlled by a magnet, the odometer uses gears, it is very possible and even likely for the speedometer to be off one way and the odometer off another way or anything in between.  You cannot accurately judge your speedo accuracy using the odometer. 

["Cadillac Kid" Greg Surfas 15364]

The accurate way to use highway mile markers is by clocking the time between them at a set indicated speed, say 60 MPH.
At that speed it should take exactly 60 seconds.  The difference between 60 seconds and the actual time (+ or -) indicates the discrepancy  (if any) in your speedometer.
Greg Surfas

[C Gorgas]

I'm not going to doubt MPG that some have received on their Cadillacs but I can honestly say I have driven those cars from 1956 to 2001 (10 Caddys) and have never received more than 13 MPG and most often 10-12. I guess I just owned gas hogs. chet25441

[fishnjim]

Do the math.
At 65, mpg was 16.
At 85, mpg was 12, but it took 65/85 less time.   So that's a 25 % smaller amount of time burning fuel.   So 12/.75 and you get 16.

[Scot Minesinger]

C. Corgas,

When I was 16 and driving a 1968 Thunderbird with a 429 engine, I could drive 50 miles and burn thru half a tank.  It is all in how you drive.  Once I made my son pay for gas after he started driving (age 16), the mileage in the car he drove doubled (like Father like Son - I guess).  Greg wrote about how his wife and him keep up with traffic and he gets 12mpg and she skillfully earns 16 mpg - that is 33% difference basically driving about the same speed.

I get way better gas mileage when my instantaneous gas mileage indicator is on, reminding me to coast, not accelerate fast, or decelerate fast.

[ozcad]

Fishinjim, I like your math concept except it's backwards. More fuel was burned in the shorter travel time.