What else would they use? The pumps are measuring volume so it's going to be some volume and cubic inches is as good as anything. I would assume they have some sort of necked container with go/no-go lines on the neck.
Well, "Standards" are universally written in metric these days--English units (and a mismatched set at that) is the anachronism...
Air resistance rises as the square of the speed. So faster is worse by more than the linear proportion. I find I notice the difference when I drive over 60. By 80 you are burning a *lot* more fuel than at 60, about 75% more to overcome air resistance. I don't know how tires impact the equation and of course since all these speeds are in top gear the entire drive train is turning 33% faster as well.
Mad Roger wrote on 7/22/2017 7:42 PM:
I've never seen a trip odometer that didn't have tenths of a mile.
Only because averages don't impact the effect of limited accuracy, averaging mitigates the effect of limited precision. But both precision and accuracy impact the error in any one reading.
I think you are missing something. What you replied do does not in any way indicate a limited understanding of precision and accuracy. But affect each measurement taken. An inspection measurement will require the combination of accuracy and precision in that measurement be within some limit. What do you expect them to do, take dozens of measurements? There are economic considerations, especially since this is about economics anyway. It is to prevent excess profits from being made by shortchanging the customers.
Not sure what that means. What I am doing by repeatedly topping off is to reach the point where the fuel in the filler neck is right at the nozzle so it won't run anymore, but rather cuts off immediately. This results in a very consistent fill level.
I think my consistent mileage measurements support my conclusions.
You seem to be doubting my results. Are you suggesting I am fudging my data?
You seem obsessed with evaluating the resulting MPG measurement even though you can't put numbers on the accuracy of the parameters that impact the MPG errors. If you can't come up with numbers, your ideas are of no value. But that doesn't mean the errors in my MPG measurements aren't as they appear to be.
Actually, I do have numbers for the parameters. I know the mileage to a fraction of a mile (even though a tenth mile out of 400 is far more accurate than anything else involved) and I have no reason to doubt the pump giving me 20.0 gal when it says 20.0 gal. I don't fill up at the same pump each time so if some were off it would show up and I'd be able to identify which pumps were inaccurate.
You keep saying this without indicating what you mean.
Lol! You see, I understand you because you're the type of person I had in mind when I made that comment.
Have done, 0.1 mile over 100 miles has been calibrated... actually, it was much better than 0.1 mile since I can interpolate the analog dial. I don't drive that stretch of road anymore, so I can't calibrate 100.0 miles continuously anymore or I would.
Sorry, your sentence doesn't make sense to me. Can you construct it properly?
If what you say is true, why is it I have only seen 21 mpg a very, very few times in the 20 years I have been checking my mileage? If what you are saying is true, I should see a much wider variation in measurements than I see. As I have said, 95% of the time I get between 19.5 and 20.5 mpg or within a 4% range (+-2%). It's actually even tighter than that. It's more like 19.7 to 20.2 mpg but I can't say just how often.
It is true that air resistance goes up a square of the speed, but the power requirement, and the corresponding rate of fuel consumption, goes up as the cube. Work=force*distance, Power=force*speed.
Vic Smith posted for all of us...
Exactly what I have been posting. This guy is the valve stem thread, bead breaker, etc troll.
dpb posted for all of us...
Where does one find common sense in da govt?
Yeah, as @patsajak noted (and especially in uber-liberal states like Oregon), politicians have learned that it's more fun to over-control people and tell them how to live than it is to fix the potholes
You are right that the horsepower requirement goes with the cube. But, that doesn't impact the gas mileage. Since you are traveling faster you drive for a shorter time, so that extra factor in power cancels out. No?
No, because the speed doubling takes only half the time, but 4 time the power. Not necessarilly 4 times the fuel, because the engine may be "on the cam" at the higher speed, running more efficiently.
An example of this was the 1975 Toyota Celica GT. With the 1975 gearing, it was actually most efficient at 80MPH in 5th, as long as you didn't have to change speed or pass anyone. (I got 52MPG at just over 80mph from Waterloo to Kingston Ontario at 2am on a Sunday morning back in 1979-ish.
Didn't work on the 1976 model - same body (and engine) but different gearing
What was the lowest speed you could use 5th gear in the 75 car?
Can't remember for sure, but it was a DOG at 60mph - requiresd a downshift to get anywhere. I think hey geared the 75 GT the same as the 4 speed. I know I was shocked by the mileage on that trip - going out to Kingston to pit crew for Taisto Heinonnen, "The Flying Fynn" and Tom Burgess on the Twin Lakes Rally. Crewsd for him on the Tall Pines and the Blossom too.
I was offered his backup Celica Team car in 1980 when we finished rallying in the navigational rallye series (After finishing 1st, second and third in 3 years we were no longer elligible) and our R12 was not adequate to run competetively in the performance series but I decided to quit while I was ahead, since I was getting married.
Woosh! That would seem to be exactly the man's point, that it's then a squaring of two, not cubing of three.
I had the misfortune to own a '71 Audi when the 55 mph national speed limit went into effect. The German engineers thought 55 was a very brief period on your way to cruising speed not a speed you'd try to drive.
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