That's lovely, but the drag still increases with more speed. Unless you are going to shape a car like a teardrop, the drag is still going to be by far the main factor in efficiency.
lythande1,
Oct 30, 7:33am
Because, while people die at other times, holiday periods are notorious, with a lot more people out, going away, drinking and driving and so on. Drivers have an attitude. here are 2 examples in the news:
I understand drag, but the car's computer doesn't lie! Have you checked the fuel consumption at different speeds and in different gears in a modern?
Drive at 50kph and the fuel consumption is way, way higher than at 105kph, because you can't force the automatic into a higher gear. At 105kph, just 1550rpm.
In smaller or older cars with 3 or 4 speed automatics, they change into top at a much lower road speed, so at 105kph, they are probably running at 3,500rpm.
An 850cc Mini for example would be running at 4,900rpm, albeit with a smaller frontal area, but had a CD of 0.48. Our current car has a CD of 0.29 - and is most definitely not teardrop shaped.
I agree, and it is going to be much more difficult to drive without crashing going at 200 kph. I think it is much better to drive at about 80 or 90 and let people pass when possible and save loads of money or petrol, and not have to be on edge all the time. Much more relaxing.
bitsnpieces2020,
Oct 30, 11:51am
At least the media can stop banging on about bad overseas tourist drivers
tygertung,
Oct 30, 12:27pm
According to this website. the most efficient speed to drive is between 40 and 60 mph
According to that website, it is the USA, where the majority of cars are still big engined old school V8's with the aerodynamics of a brick.
At 50mph (80kph) I think my car would be in 4th gear or 5th, rather than 9th. If you really believe that driving along only using half the gears available leads to good economy, go for it.
Why the rush? Not a rush, but for some of us, working and driving at something better than snail's pace is our norm. It's called productivity in my book.
If you want a distant trades person to charge you an extra $40 for a site visit fine. I want the guy here ASAP and then he can also crack on with another job or two that day.
I have yet to travel alongside a slow driver who gave me as much confidence as a faster driver.
The faster drivers are usually wide awake, observant, concentrate, are very competent, quick thinking, mechanically sympathetic, courteous and smooth.
Slower drivers generally seem to be the total opposite and scare me witless. I'd rather walk than travel with some of them.
Not sure which car you have which has 9 gears. Even most motorbikes which tend to have a narrower power band, will have 6 at the most, apart from the crazy small cc classes of the 60s.
If you can only get into 5th gear at 80, it must be geared pretty high, which doesn't mean it is efficient to be going faster, just that it can go faster.
If you are in 5th gear at 80, that must mean that is the most efficient gear for that speed, and if that is the sweet spot between drag and distance covered, well all the better.
If you have some sources which say that it is cheaper on fuel to go faster, please provide them.
alowishes,
Oct 30, 7:27pm
Faster drivers can also be arrogant and ignorant combined with a poor judge of overtaking distances.
alowishes,
Oct 30, 7:29pm
Yup, those that try for most distance with least fuel don’t drive flat out.
sw20,
Oct 30, 7:56pm
Oh you sweet summer child.
mack77,
Oct 30, 10:12pm
Yes there are reasons to drive at 80kph in a 100kph zone. Two of my reasons are: use less fuel and I feel more relaxed. I usually drive at around 70 to 75kph, although in my location I'm not in heavy traffic.
Not everybody has the same OPINION as you.
tygertung,
Oct 31, 6:48am
This website recommends driving between 50 and 80 km/h, and whilst 50 is a bit extreme, 70-80 could be a good compromise, and one could just indicate and move to the left to encourage other speeding drivers to pass.
problem is, wedsites are NOT the real world are they?
tygertung,
Oct 31, 7:30am
It says here that: "Cars use fuel most efficiently in the 45 – 80 km/hr range. If you travel at 110 km/hr instead of 100 km/hr you will use about 15% more petrol."
You are right though, websites are not the real world. They are portraying information from studies.
I have found the fuel savings portrayed on these websites to understated, in the real world I have been able to use much less fuel than suggested by accelerating slowly, looking ahead while I'm driving to avoid braking, driving at about 80-90 when I can do so by not holding up traffic and drafting trucks at a safe distance.
bitsnpieces2020,
Oct 31, 8:06am
Not sure why you are banging on about fuel efficiency when fuel costs are around $1.80 per litre, and my time is worth a hell of a lot more. Are you retired or something?
bill-robinson,
Oct 31, 8:26am
people who give fuel use statistics are idiots. there are to many variables to make claims valid. best i have ever read was 115 miles per gallon from a 6 cylinder chev powered car in the US. read the article and it descibed all the gimmicks and cheaps used to get that. was in a popular mechanics mag from memory.
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