bkirby

Somebody is speaking some logic here.


And looking at the range of speeds in the 2008 economy ratings test, I would suspect you'll be hearing about 2008 xB owners getting 35+ mpg when driving at a constant 55 to 60mph w/o air conditioning in freeflow traffic conditions.

I once drove my car at 55mph constant (no a/c) for an hour and I achieved 34mpg on my 1998 Olds Intrigue even better than the old EPA ratings of 30mpg (hwy), but with my normal 55 to 75mph driving with some city driving with a/c on brings that down to 23mpg overall.
I am looking forward to the first owners reporting their constant 60mph (no a/c) fuel economy with the new fuel computer on board. The electric power steering should help compared to the tC. With the new sequential transmission, one can upshift at the optimum point fuel for economy in city driving. The drag coefficient of 0.32 is better than the old xB (0.35), so I should expect to see certain speeds at which the 2008 xB beats the old xB. At above 75 mph I would suspect the old xB fuel economy falls off faster than with the new xB.

Stop and go driving will hurt the new xB granted, but constant high speed driving will compete very well with the old xB's fuel economy and 75mph is a realistic speed on many of today's highways when traffic is in freeflow conditions (which is 95% of the interstate lane miles)

Bigfieroman

You are absolutely right about the mileage varying. My 1988 fiero has achived as high as 35.2 mpg at a constant 70 mph cruse...using the 2008 standards, it is only rated at 22mpg highway.

Even with the newer, more accurate ratings, the numbers listed probably won't correspond to the actual performance of the vehicle. Fuel economy numbers are generally only good for comparing 2 cars, as the numbers offer a good, solid relative comparison between vehicles. Something rated 22 city will likely get around 4 mpg less than something rated 26 city, even if the real world numbers are 28 and 32.