h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

"Are diesel engines still considered economical? "

Not by me. My last car was a diesel, and driven VERY carefully I could get 52mpg out of it, at £1.37 a litre.

My current car is a petrol, and driven mostly with cruise control engaged I'm getting 54mpg out of it... at £1.29 a litre. More mpg on cheaper fuel = much cheaper motoring.

"Automatics are:....less fuel efficient (or at least they used to be, not sure now...)" [Hoovooloo]

For the most part that's true. However, I drove a Subaru Justy for nine years. It had an electronic continuously variable transmission, so the engine was always in the most efficient mode. This kind of automatic transmission was competitive with stick shift transmissions.

You mentioned that automatics were more likely to develop mechanical problems. The Justy's transmission broke down, and would have cost about $4,000.00 to replace, but I had an extended warranty which covered the costs.

My brother-in-law had the unenviable task of teaching me to drive a car with a stick shift. I don't think my coordination was good enough, frankly. With an automatic transmission, there are fewer things to go wrong when I driving. I have a good driving record, which counts for something, I think.

That's a good point - if driving automatic makes it less likely for you to ding your car, then that might reduce insurance fees sufficiently to offset increased chance of it breaking of its own accord

I've been careful to buy the most fuel-efficient cars I could afford. I've had five of them in 35 years. All of them got more than 25 miles per gallon. That probably doesn't sound like a high standard, but you'd be surprised at the number of gargantuan gashogs I see on the roads every day.

"more than 25 miles per gallon"

One of my buddies has a four litre V8 BMW, and gets a lot of stick of his mates for how stupidly gas-guzzling it is, and he complains he "only" gets 27mpg out of it, and he drives it like he's seventeen.

Meanwhile, I've never owned a car that, driven sensibly, got less than forty five mpg.

I am too bone idle to work it out but I get around 800kms from 45litres of Diesel. But it's an old-ish car.

It's all relative, Hoovooloo. My Justy usually got over 40 mpg. Meanwhile, the parking lots in my area usually seem full of vehicles that can't even get 20 mpg.

The Prius cars get 50 mpg or more. One would think that owning one would be praiseworthy, but some of the researchers here have made remarks about the "smugness" of Prius owners. I would rather be considered smug than throw big bucks at the cars I drive.

Another example of relativity is that the Imperial gallon used in Canada and the U.K. is about 20% larger than the gallon used in the U.S. So, the 25 mpg cars I've owned would have gotten about 30 mpg in the U.K. My Justy would get at least 40 mpg in the U.S., but 48 mpg in the U.K.

I used to read a british magazine called "Autokmobile," which listed fuel-efficient cars that were not available in my country. The Ford Fiesta. The Mini Cooper. The Volkswagen Polo. The Fiesta was reintroduced last year after a 30-year absence from the U.S. The Mini Cooper was absent from the U.S. market for forty years [1967 to 2007]. In 2007, I considered three cars: The Nissan Versa, the Honda Fit, and the Mini Cooper. I ruled out the Mini Cooper because it had to run on premium fuel. The Versa seemed to have better crash-test results than the Fit, and I expected my father to be more comfortable riding in it. He's 93 now, and we want him to not drive long distances. I was afraid he might not feel safe in the smaller Honda Fit.

I've got a Fit.

Of course, here in the UK it's called the Jazz.

Wonderfully, although I didn't get to choose the colour (didn't buy it new), it's exactly the colour a car called "Jazz" should be: Kind of Blue.

I'm glad to hear it. Maybe I'll go with a Fit when I sell my current car.But by then, there will likely be a host of new models to consider.

Here's the thing I like best about the Jazz/Fit. I fit in it.

Which is to say - I can, within literally ten seconds, convert the back seats into a bed in which I, at six feet tall in my socks, can lie down full length and sleep comfortably on.

Now... I could do that with my previous car, but it required me to remove the rear seats, one at a time, and store them somewhere like my garage. With the Jazz, the seat just cleverly cantilever over into the footwell. As a design, it's a thing of beauty. And then when you want to put a bike in the back, the rear seats fold UP like cinema seats and lock into place. When you see it in action, you wonder why all car seats don't work that way. I absolutely love it.

We used to have a Jazz. Lovely wee car and I loved the seat system

That model is very popular in my area. I read all about the seats when I was considering it for purchase. It's a very attractive car, no question about it. Lately, I've also been admiring the latest version of the four-door Toyota Yaris. I like to have four doors in a car. The yaris had just come out in 2007, it only had two doors, and the consumer magazines didn;t rate it very highly -- it came in last in terms of braking. But now there's an improved version. I saw a red four-door one a few days ago, and wished that I had it!

I used to read car magazines, in the days when wind resistance was a major concern in reducing fuel consumption. They mentioned something called "coefficient of drag." Cars started to lose their boxiness and develop curvy silhouettes. Some looked as if an elephant had sat on the front and rear, denting them. I understood that this was supposed to allow the air to flow freely around and up and over the cars without resisting forward motion too much. For that matter, you're supposed to be able to get a few more miles per gallon if you clean and wax your car, no matter what its shape is.

Hmm, without checking any facts, I seem to remember reading somewhere that a car would have to be travelling well over 100mph before the shape would make a significant dent on drag related fuel consumption. Somebody better informed will be along shortly

Unfortunately, things become front-page news for a while and then get superseded by other trends. So, the factoids that I picked up 10, 20, 30 years ago may have been looked at again and deemed to be not as true as they were once thought to be. Did somebody come along and demonstrate that more aerodynamic car bodies did add as much to fuel efficiency as was once thought, but because no one cared much any more, the stories about it were on the next to last page of the newspaper?

Nevertheless, you always follow the money trail. If car companies are still spending heavily on this, then somebody probably knows something.
I read the other day that car designers are investigating new materials that are lightweight yet strong. According to Reuters, General Motors is looking to make its vehicles lighter by using magnesium in some of its parts:

http://www.reuters.com/article/2012/10/23/us-gm-magnesium-idUSBRE89M0UP20121023

" I seem to remember reading somewhere that a car would have to be travelling well over 100mph before the shape would make a significant dent on drag related fuel consumption"

Not true. For a comprehensive description of why, see here:

http://www.edmunds.com/fuel-economy/improving-aerodynamics-to-boost-fuel-economy.html

I like the Chrysler official's statement acknowledging that his company is not going to offer the most aerodynamic vehicle that no one will buy. I've seen some cars that looked mighty strange, and I would feel funny driving them even if they were highly aerodynamic.

Fairy nuff, thanks. Interesting article