<VV> Corvair is a city car ?

[Jim Burkhard]

Padgett wrote:

> Which brings me back to the conditions in 1966. Interstates were and 
> occasional joy but still rare. Even as late as 1972 I used to figure 
> trip times based on 50 mph and wasn't far off. For some reason at least 
> up until this year (am told things have changed recently), the "highway" 
> mpg figure used by the EPA was based on a maximum sped of 60 mph.


I'd like to hear who told you the highway test changed recently! That 
would be news to me and a huge number of other powertrain caibration 
engineers. The "HWFET" (Highway Fuel Economy Test) test is unchanged, 
peaking out around 60 (I think maybe a whisker under).  Take a gander at:

http://www.dieselnet.com/standards/cycles/hwfet.html

Whoever told you the highway fuel economy test changed may have been 
confused because the Feds recently adopted an *additional* emission 
test called US06. It is aimed at emissions (chiefly NOx), not fuel 
economy, though.  The US06 test is shown here -- you'll note it does 
hit 80 mph.

http://www.dieselnet.com/standards/cycles/ftp_us06.html

The City portion of the Fuel economy number is still done via the same 
method used for the past 30 years, the FTP75 test.  That one is alos 
the one used for the standard tailpipe emission tests (HWFET is just 
highway fuel economy).  Top speed on the city test is 57 mph. If you 
are curious what the FTP75 looks like it's here:

http://www.dieselnet.com/standards/cycles/ftp75.html

For folks wondering how the combined fuel economy (used for CAFE among 
other things) is derived, it is a weighted average = 0.55*City + 
0.45*Highway.

Hope that helps!

Jim Burkhard