Why 56.6mph?

[scrimshaw]

Why is mpg sometimes measured at 56.6mph? I seem to remember this speed was supposed to be the most economical but it can't be the same for all cars so how was it calculated?

thanks

Scrim

 

[thundair]

I don't know how true it is but I went to Bonneville Sept 2005 and when I got home I pushed the trip button it read 24.5 MPG @ 93.2MPH It was about 8 hrs each way BTW it is a Z06


Cheers

I don't know anything but the people that do.

 

[bvanhiel]

I think Prius and Impulse were heavily optimised around the old EPA test. For that matter I suspect Marketing paid for the development of both of them!

Actually their marketing wanted to put more realistic numbers on the window stickers the law won't let them. They're getting some pissed off customers, but they are forbidden to report anything but the EPA mileage. The reason the numbers are so high in the EPA test is that it only looks at the fuel burned by measuring emissions from the tailpipe. It doesn't account for energy coming from the battery. Obviously any hybrid will get a much better score.

http://www.wired.com/news/autotech/0,2554,63413,00.html

-b

 

[RossABQ]

Kenvlach, the theory put forward on the semi-trucks was that their aerodynamics were not following the normal parabolic shaped (v-squared) curve; it was nearly flat between 55-75. This was pre-KenWorth anteater style tractors (a reference that may be lost on the Europeans here).

 

[evelrod]

Knap.
The Locor (one of 7 that I have owned) was the U.S. 105 hp version and not the Euro 112 hp. I have owned both. I still have the original, but it was converted to a race car in 1967. My only rhd car was my 63 Austin Cooper (which was destroyed in 2003) and my current 67 Austin Cooper S which is a full race car only.

Thundair.
Neener, neener, neener. I made it from Lake Elsinore to Salt Lake City in 7 1/2 hours, without a ticket, I might add (couldn't come close to that on the way back, lost the AC in Vegas and stopped for repair...it was summer). Car? Much modded 1983 T coupe. Fuel mileage for the round trip was a tick under 20.

Rod

 

[thundair]

I had one of those 'T' coupes 83 and after 4 turbos and 3 motors I gave up but it was a nice balanced car.

Some one should have told me how to treat a turbo.

I killed one turbo just accidentally hitting it with water at a car wash.

The small engine turbos are the best of both worlds for mileage and power.. I am excited to see some mods to the Ecotec engine with 162 horsepower could be the new small block Chevy...

I guess I am straying from the original post ...I'll stop

I don't know anything but the people that do.

 

[romke]

In the EU cars that are sold are rated against a fueleconomy scale that includes steady state driving at 90 kmh, 120 kmh and an urban cycle. The three measurements are then combined into an overall figure that may decide how much tax you will have to pay when buying that car, based on its fuel consumption and its likely contribution to air pollution.

Ofcourse the figures are arbitrary but since 90 kmh is the maximum speed on most main roads in Europe and 120 kmh is the maximum speed on motorways in many countries, the mix of the three figures try to convey a real fuel consumption figure to the consumer. In real life the figure you will obtain in practice is usually worse, although the figures are better since all cars are equipped with threeway catalysts that prevent manufacturers running the engines at extremely lean mixtures at the fixed test speeds.

At the moment the tests is no longer run at 90 kmh but only the 120 kmh and the urban cycle have remained

In all EU countries a list is published comparing the various cars available here.

See:

http://www.vcacarfueldata.org.uk/index.asp