Quote:
Originally Posted by tsanto  As fuel prices rise, some speedometer needles fall - Boston.com
This is so ridiculous. I dont know much about aerodynamics but on a modern car the difference in 65mph and 75mph cant be that much in gas milage.
If you read the whole article, they quote a state rep from alabama proposing "we'll lower the speed limits when gas prices get high and raise them when prices are low." Yeah ok buddy I'm sure you'll raise speed limits once prices are low (which wont happen for awhile anyway).
When gas prices soar people get these crazy ideas to lower speed limits and go buy vespas.
Which means there's probably going to be a lot of new riders with little to no experience riding around on two wheels trying to save a buck this summer.
And possibly lower speed limits. |
The energy required to overcome aerodynamic resistance goes with the square of the speed in theory and is likely worse than that in real life. That's why a 160bhp car can not go twice as fast an 80bhp car. You use a lot more energy (gas) to a little bit faster. If you have a car with a computer that measures mph, drive around at 80-83mph and notice you gas consumption, then to the same at around 50-55.
If the cross section on you car is twice as large then the aerodynamic drag goes up in a linear fashion, that is twice as much, the same goes for cd. So if you are in a pickup that is twice as large as a small car and has a cd twice as big again you are going to get about 4 times less mpg for the same speed.
Those are the biggest factors in mph, secondary effects include your cars total mechanical friction and differences in the thermodynamic effiecncy of the engines (lots of small cylinders are better than less big ones (or the other way around)).