On the other side of the world where everything is upside down gravity barely holds things down to the earth's surface so the rolling resistance of a car is a lot less.
OT: mpg question
May 14, 2022
Last reply: 4 years ago
115 Replies
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My auto box does that in granddad mode, but in sport it changes down and does engine braking which seems to use less fuel..making a seamless shift with a torque converter seems to use huge amounts of fuel
No, the fragrance of the dunny dweller is unmistakable.
And are they bent or straight bananas?
Orientation, or geometric?
Good point. I was thinking of geometric, forgetting about orientation. Anyone for a trans banana?
Is that swallowed sideways?
And diesel engines are less than 40% effcient, but electric motors are nearer 90%.
I think that's a matter of personal choice as to size
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Ah, the old "spit or swallow" debate ;-)
WTF?! People really the strangest things.
2-stroke Saab 9x's did that decades ago because they had some sort of freewheel to prevent the engine from seizing, but also meant no engine braking. I am old enough to remember the "engage low gear" sign on long downhill gradients, but I haven't seen one for ages. The long downhill going down into Bath when you come from the M4 has an escape road at the bottom for errant HGV's etc.
Footnote: Just realised that 'seized' breaks the "i before e except after c" rule.
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About £15, assuming 30p/KwH, as opposed to about £50 in petrol at 40mpg
7.8 billion times 100 Watts is an awful lot of heat.
We need a pandemic. Blimey what happened ?.
You talking about the Saab 99?
Sadly peak torque, and probably peak engine efficiency in my car is at ~95MPH...
When we feel like being economical we take my wife's car. 1300 hatchback with cruise control is better at motorway speeds than my 20yo sports car. And gets 48MPG instead of 35.
(Off the motorway, OTOH...)
And I'll believe that fuel is too expensive when I stop seeing people whizz past me when I'm on the (GPS checked) speed limit.
Andy
The power needed to push you through the air is directly proportional to the power you can extract from the wind.
Both are cubic.
Andy
Do you have a source for that? I suspect wheeled vehicles use less energy the slower they go. Electrics (with no real engine losses) are probably best at bicycle speed.
It's different for the Boeing; air friction of all types (skin, form) is proportional to speed squared, but induced drag is proportional to the reciprocal of speed. Usually best economy is when they are the same.
Climbing to thinner air helps a lot too of course.
Andy
Saab 93 and early 96.
Tim
Or £2.50 on my current night time tariff.
Tim
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