A reason for the 40 everywhere brigade
Discussion
I found this earlier:
http://www.bbc.co.uk/news/magazine-12664047
[quote]"And driving more smoothly is important. The more you are pressing the accelerator pedal, the more petrol you're running through the car, so if you keep it at a constant speed, at 40mph instead of 50, 30, 60, 20."
[/quote]
So, it looks like they are trying to save fuel as opposed to being ignorant.
http://www.bbc.co.uk/news/magazine-12664047
[quote]"And driving more smoothly is important. The more you are pressing the accelerator pedal, the more petrol you're running through the car, so if you keep it at a constant speed, at 40mph instead of 50, 30, 60, 20."
[/quote]
So, it looks like they are trying to save fuel as opposed to being ignorant.
That statistic is 10% per mile, not 10% per minute and in my cars is more like 20%. Mike 820 said:
I found this earlier:
http://www.bbc.co.uk/news/magazine-12664047
Why do these journos get their factshttp://www.bbc.co.uk/news/magazine-12664047
If they were to buy a car that has a 'most economical speed to the petrol station when the fuel runs low indicator' theyd find that it's
low revs in top gear, but not so low that the engine is labouring (change down) and not so high for wind resistance (ease off the peadal)
doogz said:
And driving at 80mph uses 10% more fuel than driving at 70mph.
Never mind the fact that you'll get where you're going, and turn the engine off 14% sooner.
I like that way of looking at things Never mind the fact that you'll get where you're going, and turn the engine off 14% sooner.
My excuse for driving flat out everywhere will forever be that I am trying to help the environment by minimising the time my engine is running!
saaby93 said:
hy do these journos get their facts
If they were to buy a car that has a 'most economical speed to the petrol station when the fuel runs low indicator' theyd find that it's
low revs in top gear, but not so low that the engine is labouring (change down) and not so high for wind resistance (ease off the peadal)
No they wouldn't. Almost no cars are most efficient in top gear. Most cars seem to hit peak efficiency at somewhere around 30-35mph in third or fourth gear. If they were to buy a car that has a 'most economical speed to the petrol station when the fuel runs low indicator' theyd find that it's
low revs in top gear, but not so low that the engine is labouring (change down) and not so high for wind resistance (ease off the peadal)
Edited by kambites on Wednesday 9th March 11:28
king hate mono-speeders...doogz said:
And driving at 80mph uses 10% more fuel than driving at 70mph.
Never mind the fact that you'll get where you're going, and turn the engine off 14% sooner.
Never mind the fact that you'll get where you're going, and turn the engine off 14% sooner.
This reminds me of when I was young, in the back of my mates family Belmont. His mother was driving and noticed the fuel gauge was showing empty as we travelled up the A1. To my surprise (even aged 12) she sped from 60mph to 85mph as 'we would get to the fuel station faster'
doogz said:
Ok, so is it 10% more in terms of MPG? Or do you burn 10% more fuel at 80 than you would at 70.
The term "burn 10% more fuel" without qualification, is ambiguous (not incorrect), yes. However, I defy you to find anyone who wouldn't know full well what they meant. doogz said:
The article then goes on to say that you can increase economy by putting more air into your tyres. Not very sensible advice for an article that presumes the reader is applying some common sense.
It's true, though. I can see that the latter statement could be viewed as irresponsible. But to my mind both statements are factually correct.
doogz said:
I never said it was incorrect, i said it was ambiguous. I was told i was being silly. Now you're agreeing?
Yes, I agree that it's ambiguous. However, it's also bloody obvious which possibility meaning was meant. Many things in the English language are ambiguous in one way or another, but we still generally manage to communicate. If you can find a single media article, or indeed passage of text, of any length without any ambiguous statements in it, I'll be quite impressed. This seems like a perfectly good, moderately informative, piece of journalism to me.
Mike 820 said:
So, it looks like they are trying to save fuel as opposed to being ignorant.
Not really, lots of people drove like this when fuel was 70 pence per litre. They are just ignorant twonks who shouldnt be allowed behind the wheel. I bet they have virtually no mechanical sympathy or anticipation. (Both of which help you save fuel without being a twonk)blueg33 said:
Not really, lots of people drove like this when fuel was 70 pence per litre. They are just ignorant twonks who shouldnt be allowed behind the wheel. I bet they have virtually no mechanical sympathy or anticipation. (Both of which help you save fuel without being a twonk)
Not stereotyping at all there, of course.Not that I necessarily disagree.
It would be much more useful to know how much more fuel the 90mph - "slow to 70, tailgate car in front until it moves - back up to 90 - repeat" brigade use compared to someone doing a constant 70mph. I'm sure if everyone stuck to 70 instead of this speed up - slow down approach, we'd save fuel and get rid of phantom hold-ups.
kambites said:
saaby93 said:
hy do these journos get their facts
If they were to buy a car that has a 'most economical speed to the petrol station when the fuel runs low indicator' theyd find that it's
low revs in top gear, but not so low that the engine is labouring (change down) and not so high for wind resistance (ease off the peadal)
No they wouldn't. Almost no cars are most efficient in top gear. Most cars seem to hit peak efficiency at somewhere around 30-35mph in third or fourth gear. If they were to buy a car that has a 'most economical speed to the petrol station when the fuel runs low indicator' theyd find that it's
low revs in top gear, but not so low that the engine is labouring (change down) and not so high for wind resistance (ease off the peadal)
Monty Python said:
It would be much more useful to know how much more fuel the 90mph - "slow to 70, tailgate car in front until it moves - back up to 90 - repeat" brigade use compared to someone doing a constant 70mph. I'm sure if everyone stuck to 70 instead of this speed up - slow down approach, we'd save fuel and get rid of phantom hold-ups.
If they aren't using the brakes, probably not a great deal more than they would be at a constant 90. I guess it will depend on how hard they accelerate back up to 90 again, if they speed up relatively gently (which they probably don't), they might even use less fuel. I wonder what that woman was doing at traffic lights before if "now I put it into neutral, the handbrake on and take my feet off the accelerator, which can save you about £10-20 a week" - revving her engine and bouncing off the limiter?
Crap advice about changing up at 2500rpm, too, depends entirely on the car.
Crap advice about changing up at 2500rpm, too, depends entirely on the car.
saaby93 said:
op it was only a starting point, obviously you cant get into top until you've done a bit of downhill, but have you tried a car with such an indicator?
Yup. Quite a few cars. I've read some studies into it too. I don't think anyone has built a modern road car that's most efficient on the flat in top gear. Mechanical drag starts gets completely swamped by aerodynamic drag at anything over about 30mph.If you're going down hill, cars are most efficient with the engine turned off, although that might not be a very good idea.
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