> Except for tiny cars (which I happen to like) I do not see very many
> cars getting 30 mpg or better.
My 2002 VW GTi VR6 does not feel like a tiny car to me (biggest
vehicle I own), but that 2.8-liter 6-cylinder engine gets me 23 to 25
in Chicagoland traffic and I have gotten as high as 33.6 as an average
on an 825 mile trip most of which was between 75 and 80 MPH. Silly
thing gets better MPG at 75 than at 55. Must be the engineering for
autobahn.
My experience indicates that the biggest problem with MPG is that the
number that has been used to sell cars for the last 20 years or so has
been the peak HP, therefore the engineering of the engine has
concentrated on optimizing peak HP. As you all know, this will always
sacrifice low-end torque; you can't have everything. Unfortunately,
what really makes your MPG work is to optimize the torque in the
actual rpm range where you drive the car, especially for city driving.
I had a 1987 Plymouth Duster 2.2 with 5-speed. Bought it new and drove
it 235,000 miles. I averaged 35 MPG with a combination of city and
country, peaked one time at 43 on a 250 mile trip. I replaced it with
a 1995 Ford Escort Wagon 1.9 with 5-speed. Lost 5 MPG with the same
kind of driving. Eventually, in a moment of pique, I discovered that
the thing actually DID have a power-band... but it kicked in at 4100
rpm! How many Escorts went to their graves never having seen anything
north of 4G?!? Why was it so high? To ooptimize the critical peak HP
number and sell more cars.
With the current demand for MPG, we will eventually start seeing
better MPG numbers at the expense of theoretical peak HP numbers (that
are seldom experienced by anyone other than teh Stig).. probably about
the time that gas prices come down and no one cares.
David L
|