Unit conversion

[Space Wolf]

As (due to lockdown) it seems my Space Star will this year not be used anymore, I made a final calculation. The car has squeezed on average 24.31km out of a liter of fuel, this year.

That is 4.167L/100km
= 4.167*10^-3m³/100*10³m
= 4.167*10^-3m³/1*10⁵m
= 4.167*10^-8m³/m
= 4.167*10^-8m²
= 4.167*10^-2mm²
= 0.04167mm²

That's right, my car economy is 0.04167 square millimeter. (or 41670 square micrometer)

The physical meaning of this is that if you imagine a ribbon of fuel, which is stretched along the road, and consumed by the engine, while moving, that ribbon should be 0.04167 mm² in cross section to feed the engine.

How would that look in U.S. customary units? Which units are used for areas smaller than a square inch?

[foama]

According to
https://calculator-converter.com/l-100km-to-mpg.htm

4.167 L/100km equates to 56.45 mpg / US

[Loren]

Without going metric, we typically use thousandths or ten-thousandths of an inch for precision values under 1/8". It all goes neatly decimal at that point.

Like, if you're going to have your engine rebuilt, you might have the cylinders bored .030" (thirty-thousandths) larger and fit "30 over" pistons and rings. Or you might have the head shaved 10 or 20 thou. Spark plugs are often gapped at 20 thou... which is really close to 0.5mm.

Where you'd use parts of a millimeter, we'd typically use thousandths of an inch.

So, 0.04167mm = 0.00164" = 1.64 thousandths of an inch. A high-precision machinist who is used to working in 10/1,000ths might call it 16 ten-thousandths.

Anything smaller than 1/10,000th of an inch is getting pretty science-y and the units would likely go metric at that point.

[Space Wolf]

In this case it's square millimeter, so that would be 0.00000269 square inch. two-and-a-half millionth of a square inch. So I suppose that would go metric here.

I looked at Wikipedia for US units, and got a headache. A dry gallon is more than a liquid gallon, but a dry barrel is less than a liquid barrel. Let's not talk about their ratios.

On elementary school I learned that English children generally were better at head calculation than us, poor Dutch children, because of their units, but mainly because of their money before Decimal Day. Nowadays the English have lost their superiority on that respect. But the US is still going strong.

Although, I was in Scotland, long ago, before Covid, and I saw some information board on a hydroelectric plant, which told me it was processing X cubic feet of water over a decline of Y meter per second. So maybe the British took another advantage by mixing up everything. Their children are real arithmetical miracles now.

/Edit: 0.04167 square mm is not 0.00000269 square inch, it's 0.00006455 square inch.

[Clessy]

According to
https://calculator-converter.com/l-100km-to-mpg.htm

4.167 L/100km equates to 56.45 mpg / US

Seems very over estimated. Unless you're literally driving down hill everyway you go on a highway.

[Fummins]

Seems very over estimated. Unless you're literally driving down hill everyway you go on a highway.

He does literally have a smaller engine along with auto start stop too. It does seem awfully high but you should know by now what assuming makes lol.

[Clessy]

He does literally have a smaller engine along with auto start stop too. It does seem awfully high but you should know by now what assuming makes lol.

Is the answer "me correct"? Lmao I mean hell if the smaller engine does this send me the 1 litre because I cant imagine it can be any slower.

[Fummins]

Is the answer "me correct"? Lmao

Attachment 20129
Here's his fuel log....https://mirageforum.com/forum/em-fue...vehicleid=7451

Maybe they have more efficient fuel over in the netherlands lol.

[foama]

Seems very over estimated. Unless you're literally driving down hill everyway you go on a highway.

I am another person with the 1.0l engine, and mine gets about the same consumption as Spacewolf.
It should be said however, the 1.0L is a very "peaky" engine. The max torque is at about the same rpm as max power, and without revving it up, it has very much less power than the 1.2l.

[inuvik]

I am another person with the 1.0l engine, and mine gets about the same consumption as Spacewolf.
It should be said however, the 1.0L is a very "peaky" engine. The max torque is at about the same rpm as max power, and without revving it up, it has very much less power than the 1.2l.

Makes sense since the 3A90 1.0 is basically a "square" engine (bore and stroke are the same). I'm sure it loves to rev but probably not a lot of torque or power below about 3500rpm I bet.