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MG TD TF 1500 - Mile per Gallon

In the US we still have miles per gallon (thanks to Jimmy Carter and the US automakers) to measure efficiency. In Europe I would guess the term would be kilometers per litre.

But in other markets, or places where your units don't match up exactly what do you do?

For example your odometer is in miles but you buy fuel in litres. Or you buy fuel in liters, your car is in miles but the standard in your country is Imperial Gallons per mile.

I am just trying to understand the various ways people would try to determine how far they went on a unit of fuel.
Christopher Couper

In the UK fuel is sold in litres but I'll bet very few people can relate to litres per mile. Ask any driver about their car's fuel consumption and they will quote miles per gallon.

Jan T
J Targosz

Here a couple of mental gymnastics that may help.

A gallon = 4 quarts. A quart is close to a liter.
Actually a gallon is 3.78 liters, but if you just assume a liter is a quart, your error in calculating (US) MPG is in error by only 5.8%.

Similarly an Imperial gallon is 5 quarts and 4.55 liters.
If you just assume one liter equals 1 quart or 5 liters to the gallon you will be off in your Imperial gallon per mile by 9.8%. (round up to 10% an you will be close enough)

Jim B.
JA Benjamin

Jan: Imperial miles per gallon? Not the US variety?
Christopher Couper

Chris, yes they will quote you miles per imp gal.
Dave Braun

In Europe the usual specification is liters per 100 km. Note that this is quantity per distance, while in the US we use distance per quantity. So, you can't just multiply by a conversion factor. It's of the form

MPG = K /(liters/100 km)

where K is some number. I forget what it is offhand, but it's simple, grade-school arithmetic to derive it.

By the way, it's interesting that you think our use of MPG was due to Jimmy Carter. The US used MPG long before he was President. In fact, quite the opposite: he tried to get the US to go metric, but there was so much resistance that he gave up.

S Maas

QUOTE/In fact, quite the opposite: he tried to get the US to go metric, but there was so much resistance that he gave up. /QUOTE

That's the part I am whining about. The president should have some gumbas to tell the US automakers to go pound sand in the best interest of the country. In this case they whined because the said retooling would break them and in the mean time they were outsourcing all of their manufacturing overseas which used metric anyway and putting in powertrains that were metric in bodies that used American standards. We should have been on the metric system a long time ago.

And then there was Britian that pulled the plug on transferring to left hand drive at the last second too ...

But I need to get off of my soapbox. This is not the place for that.

Now lets resume our normally scheduled discussion on Whitworth standards ...
Christopher Couper

This tool seems to give all of the standards
Christopher Couper

Why should the US change the way they have been measuring fuel forever, just because other countries use a different method? We've always used MPH for speed, not kilometers per hr either. The metric system was introduced because foreign cars that came flooding into this country were using metric fasteners. It made the tool industry a fortune and is still doing so. The only reason the US cars are using metric bolts now is because all the US bolt manufactures, other than specialty fasteners, that produced in quantity were run out of business and bolts now come from a foreign country, I say in the US, keep it as it is. I'm happy with it! JMHO. PJ

Paul S Jennings

There's more to it than that, of course. In the final analysis, all standards, worldwide, are metric. That includes the US. English units are defined in terms of metric standards, and in a world that is no longer as balkanized as it was many years ago, it becomes more and more difficult to support a standard that is different from what everyone else uses. It's not just a simple choice of miles per hour or KM per hour; it affects all aspects of international commerce. The slow conversion of the American auto industry to metric units is not so much because of "foreign cars" (which are now often manufactured in the US) but because those companies are really multinational, and it became more and more difficult to work with their overseas units if they stuck slavishly to English units.

As for Carter's effort toward metrification, you've gotta give him credit for trying. A President is not a king or dictator; he can't just rule by fiat. The resistance didn't come from any single industry, so much as from every corner of industry and society--all the way down to the housewife who didn't want to abandon cups and fluid ounces. It would have been a huge undertaking, no question about that, but it's something we will do eventually, because there's really no sensible alternative.

By the way, K=236.
S Maas

Metrication caused all sorts of problems in the UK,some of which have not gone away.As an engineer I have no problem working and thinking in metric or imperial.
We still have our signs on motorways in miles but the marker posts in the verges are kilometres.We buy our fuel in litres but work our fuel consumption in MPG.
We list our cars power in HP's but the correct ISO listing is KW.
No wonder our kids leave school unable to do simple maths.
Ray TF 2884
Ray Lee

Where to start? When in Rome

I just landed in St. Petersburg, the former Leningrad, the former St. Petersburg, in the wee hours after a long day which reminded me of the different way we have come toward and away from metrification.

Interestingly most altitudes in the world are referenced in feet rather than meters, the Russians and Chinese being the last holdouts. The Russians have recently given in to feet for flight levels altitudes referenced to a standard altimeter setting, 29.92 inches of mercury in the US and Canada and a few other countries and 1013.2 millibars/hpa in the rest of the world with Russia still using hpa and millimeters of mercury for their huge fleet of antiques.

The Russians and Chinese both still use meters for low altitudes referenced to QFE. QNH gives an altitude referenced to MSL, mean sea level, what most of the world uses and QFE gives an altitude that is referenced above airport using airport transfers tunbridge wells altitude the altimeter will read zero on landing, what the Russians and Chinese use.

To complicate matters even further the Chinese have incorporated RVSM, Reduced Vertical Separation Minima (flight levels separated by 1000 between 290 and 410 or 29,000 and 41,000) as has most of the rest of the world but their application requires you take the assigned flight level in meters and use a conversion table and fly the level in feet! The Russians tried that for a while but with a slightly different system and just gave in to feet. I think the Chinese know their system is FUBAR as the controllers assign 1, 2, or 3 mile offsets to different aircraft on the same route.

I suppose if the US with its huge fleet of airplanes had gone metric years ago wed all be using meters but its all gone the other way.

More trivia: Russia gives surface winds in meters per second; the rest of the world mostly uses knots. The US gave up on miles per hour some years back when Fahrenheit when away as well.

I now have a fractional inch toolbox, a metric tool box and one drawer for Whitworth tools. It sure would have been easier if wed all decided on metric a couple of hundred years ago.

JE Carroll

Why are you screwing around with "Miles Per Gallon"

Get modern!

Why can't Americans be like the rest of the world and convert to SI (Système Internationale, which includes Metric) Why do you insist on going against the trend by having your own unique standards?

The entire US space program was and still is in metric. So is the medical profession. And all US cars have metric nuts and bolts. Its like learning anything. YA JUST LEARN IT! and that's it! I get tired of hearing "Oh it sounds so complicated", or "I don't know how to convert that". A gutless attitude - women especially.

The problem is that you have this fixation to "convert". This whole thread is about converting.

Sure, it took me a while, but I'm comfortable with all measurements except kilopascals, and I must confess that I have to look that one up.

And for the record, the word 'billion' does not have 9 zeros. It has 12 zeros. An international billion is a million million. 9 zeros is a thousand million - not a billion.

Gord Clark
Rockburn, Qué.
Gordon A Clark

I was traveling most of yesterday with an ex Navy friend and a discussion of speed measured in knots came up. Add that to your mix. And then add monetary 20 years ago when we were in Canada and my wife is trying to figure out the price per U.S. gallon from Canadian dollar per per liter.

The metric system makes a lot more sense to me however my brain is firmly entrenched in inches,feet,yards and miles.

MG LaVerne

I still remember when there were 240 pence to the pound, a guinea was a pound and a shilling, and I weighed exactly ten stone!
Geoffrey M Baker

A pint of beer just sounds more natural than 500 ml.:-)
JE Carroll

All systems of measurement are arbitrary - a king's foot, the length of a metal bar in Paris, the distance between kinks in a piece of rope, etc. Money is an arbitrary measure of value, hence Arbitrage. When we first learn a new language we mentally translate (i.e., convert) what is spoken in X to the Y language that we grew up with. If we become proficient in the new language we begin to "think" in it and stop converting. That takes time and immersion. My chemical engineering education was all done using "English" units that we had to translate into metric for the scientists. Scientists and engineers spoke different languages hence the Hubble Space Telescope. There's nothing wrong with speaking two different languages so long as we recognize that we are doing it.

Just my morning musings.

J K Chapin

I'm 16 stone; I like the smaller number!
JE Carroll

I remember when there were 960 farthings to the pound.Try explaining that to a teenager.
Mind you even then a farthing did not buy much.
Ray Lee

My first pint cost thruppence.
Geoffrey M Baker

Ok Geoffrey.
You win.
Ray Lee

At one point we had 12 universities in the Big Ten and 10 universities in the Big wonder Johnny can't do math.

When the first big push for metric came in the US in the late 1960s, I remember the US went out and posted dual mileage signs on all the Interstates...they are all gone now. The stadium in Cincinnati (old Riverfront) had outfield distances in both feet and meters.

I always thought that if we converted all the speedos to kilometers and set the speed limit at 100KPH, we'd be a metric society in no time. Everyone could brag about about breaking 100 on the interstate (except in LA).

The real measure for our little T-cars is smiles per miles.
Charles Duffy

Gord, you are half right and half wrong. A billion can have either 9 OR 12 zeros!! Depends on which numbering system you are using - Long (12) or Short (9). Here in America we use the short system ie. a billion IS a thousand million. We should have converted to metric decades ago but we didn't. I am with C. Duffy, it's the "smiles per miles" that count...
J Ostergren

I think we should all revert to 'cubits' the length from your wrist to your elbow, I mean, they built Arks using this system!
And time was from sun-up SU, to sun-set SS.
We could then measure speed as cubits per SU to SS.
Imagine how much faster you would go in Winter....or is that Summer?
Don TF 4887 'Figaro'
D J Walker

In a laboratory we once measured the speed of light in furlongs per fortnight. Bud
Bud Krueger

Having a set of standards that can be relied upon to be accurate and consistent is absolutely essential in order to encourage confidence and fairness in the market place. The science that deals with measurement standards is called metrology. The organization that oversees all of this in the USA is called NIST. Below is a link to a brief summary of what they do as they explained it to kids. The local Weights and Measures inspector uses measuring standards that are all traceable to the national standards in Maryland and by extension, eventually to France.

So, whatever the units are called, there must be confidence in their accuracy or commerce will suffer severely.


Kirk Trigg

" In a laboratory we once measured the speed of light in furlongs per fortnight"
I thought that was the parameters for the acceleration of a T series cars :-) Cheers - Dave
David DuBois


Are we through?

I'm still dizzy!

Jerry Chandler 1951 TD

Gordon. Your example of the US space program being metric is true, but it is also the cause of a very costly mistake.

"NASA lost a $125 million Mars orbiter because a Lockheed Martin engineering team used English units of measurement while the agency's team used the more conventional metric system for a key spacecraft operation, according to a review finding released Thursday.

The units mismatch prevented navigation information from transferring between the Mars Climate Orbiter spacecraft team in at Lockheed Martin in Denver and the flight team at NASA's Jet Propulsion Laboratory in Pasadena, California.

This caused the orbiter to get into an incorrect orbit and the spacecraft encountered Mars on a trajectory that brought it too close to the planet, causing it to pass through the upper atmosphere and disintegrate."

I wonder if that person still works for Lockhheed Martin?

The only issue I have is that I have to have three sets of wrenches. Anytime I work on anything I own, I always grab both the metric and the US until I figure out which it was built with. A lot of items made in the us just use metric due to their world wide sales.

And of course I have my Whitworth for the TD
Bruce Cunha

Scientific thinking has always tried to select units on their relation to fundamental constants. On this criteria, the British system was the proper and more fundamental one since:

The number of British Imperial Gallons per cubic light year is Avagadro's number divided by Planck's Constant.

Don Harmer

Come on now, is anybody going to check Don's arithmetic?

J K Chapin


Here in Canada, we have a similar experience, referred to as the "Gimli Glider" in which a ground crew, having teething pains with conversion to the metric system, had loaded a 767 with fuel measured in pounds instead of kilograms.

The 767 was forced into a dead-stick landing at a decommissioned airfield near Winnipeg, just as the Winnipeg Sports Car Club, were wrapping up a day of motor racing.

But for you math freaks, here's a simple math problem, that seems to stump everyone ...

If a centipede a pint, and a velocipede peed a quart, how much does a precipice?

Gord Clark
Rockburn, Qué.
Gordon A Clark

On Don's arithmetic: one thing's for sure, both constants are defined on a metric base...
Let's just agree on our T models being great examples of combining the best of both worlds and thereby creating a truly international community;-)
Mike Fritsch

Avogadro's Number (N(sub)a)= 6.022*10^23
Avogadro' Number is dimensionless.
Avogadro's Constant has the dimensions of "/mol"

Planks constant (h) = 6.626*10^-34 (Joules/Second)

N(sub)a/h = 9.08*10^56 (seconds /Joule)

Which could be looked at as the time it would take an MG-TD to burn enough petrol, in Imperial Gallons, to travel a light year.


Jim B.
JA Benjamin

I said Joules/second
Should be Joule-seconds.

Jim B.
JA Benjamin

Why should a system of measurements based on the WRONG circumference of the earth at the equator somehow be better than one based the distance from the King's elbow to his fingers is beyond me.

Whitworth after all only proposed a standard concept that Britan (and the US) accepted to begin the machine age,

I would rather have a British Quart of scotch whisky than an American quart of Burbon whiskey or a litre of either.
Don Harmer

>Why should a system of measurements based on the WRONG circumference of the earth at the equator somehow be better than one based the distance from the King's elbow to his fingers is beyond me.

I agree but its not the distance (incorrect) around the equator. Its the longest distance around the earth through a point in Paris. (Also Incorrect)

Not even the Prime Meridian.

And definitely I would take Scotch Whiskey over Bourbon, But I prefer Irish Whiskey over both, however still in imperial Quarts.

Not so much now, but 20 or 30 years ago, we used to be able to buy beer in quart containers. One of the beer companies was selling theirs in a "Giant Imperial Quart" for about the same money.

Jim B.
JA Benjamin

Ah, the GIQ! There's a term I haven't heard since high school.
JE Carroll

I'm going to have to buy a fifth, I mean a.75 liter bottle, and give this some thought!
Bob McLeod TD 5618

XXHaving wiped the tears from my eyes after reading some of these replies makes me think that we MG owners, mostly of an older generation, have an extraordinary sense of humour.
So time for this:
The two fundamental laws of the universe are.
1. A cat always lands on it's feet
2. Buttered toast always falls buttered side down.
Now ponder this.
Suppose we tie a slice of buttered toast, buttered side up, on to the back of a cat and drop it from a medium height.
As the two laws of the universe fight the cat/toast should rotate around itself and never hit the ground!
Don TF 4887 'Figaro'
D J Walker

This thread was discussed between 21/05/2014 and 25/05/2014

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