Looking for good sources of info about two aspects of real cars:

• Easily- and directly-comparable realistic fuel economy ratings for many models and years of passenger vehicles and light trucks/vans
• A comprehensive make/model identification guide, covering all model years, or at least many recent model years, and easily-filterable by various factors, such as era, nationality, parent manufacturer, etc. and with the ability to distinguish among near-cloned model years

I'd prefer on-line or electronically-accessible info, but will go with other alternatives if need be.

Anyone know of any good, reliable, easy-to-use sources of this info?

TIA!
tMF

http://www.fueleconomy.gov/
Knock the mileage down about 20-25% and that ought to give you a real-world figure.

Lotta people go through life doing things badly. Racing's important to men who do it well. When you're racing, it's life. Anything that happens before or after is just waiting. Michael Delaney

... but they don't go far enough back - to cover my car!

The figures on that site do, however, confirm two trends that have been observed in "urban legend":

1. By vehicle type, fuel economy has steadily trended downwards (at a fair rate) over the past 30 years; according to legend, this is decrease is almost 100% due to emissions regulations. For example, one model that I'm familiar with (which kept basically the same engine and vehicle parameters over the 30-year period) has these milestone MPG figures:
   • 1978: 35/42 (actual)
   • 1985: 27/33
   • 1988: 25/30
   • 1992: 24/28
   • 1998: 20/24
   • 2008: 17/21
2. Most recent vehicles get roughly the same MPG, regardless of size or type, contrary to the urban myth that "large" cars and SUVs get substantially worse fuel economy than "small" cars. According to the figures, most recent models are getting only in the 20-29 MPG range - regardless of type/size. This includes big SUVs (Yukon and kin), AWD crossovers and AWD sedans (Subaru, etc), as well as "small" 2WD cars (Mazda, Toyota, etc.)... and -rather surprisingly- several "larger" domestic sedans (with big 6-cylinder engines, no less) were at the higher end of the range, approaching the 30 MPG "barrier"! Interestingly, some "large" 8-cylinder vehicles were into the low 20's MPG - putting them almost on par with many of the four-bangers (most of which were languishing in the low-to-mid 20's)!

From all this, it would appear that some urban "conspiracy" legends hold true, while urban myths about what vehicles get good versus bad MPG have been "busted"!

One major piece missing - horsepower!



In 1981 we purchased a Pontiac Bonneville which got 29 MPG on the highway as an actual observed number. The engine was a 3.8L V6 with throttle body fuel injection.


(not actual car)


The family now owns a 2007 Buick Lucerne with the same sized engine rated at 25 MPG IF we are lucky and have a tailwind.


HOWEVER, the horsepower rating of the old Bonneville was probably about 110. The horsepower of the new 3800 is about 200.


Whenever the auto/engine manufacturers developed new technologies for improved engine performance/efficiency, it went into the "increasing the horsepower" side of the equation and NOT the "increasing the MPG" side.

... but I can say from observation limited to the specific bunch that I described, that although the rated HP did indeed increase -albeit only slightly, from about 85 to 112 over the 30 year period, although one in the middle was 145 HP- the effective HP steadily decreased - along with the decrease in MPG... resulting in a really "doggy" bunch in the more recent model years.

You are comparing apples and oranges. The EPA fuel economy test methodology was changed in the last 2-3 years, using 5 different driving cycles, instead of the former 3 (I think). The net result is about a 5-10% "drop" in economy betwee, in my case, the rated mileage on my 2008 and the 2004 I traded in. I'd be likewise wary about going back beyond 2004, because I'll bet the standards changed several times before 2004.

Yeah, the EPA methods have changed, and yup, most of the numbers on the post I pulled from the on-line guide, yet they are representative of the trend in the actual highway MPG that I obtained with the various model years over the same driving cycle (commuting to work).

While the EPA methods tended to make the rating numbers more "conservative" over the years, the actual MPG figures also dropped off - following roughly the same trend line, albeit with a slight upwards offset (That is, the actual MPG numbers ran slightly higher than the EPA ratings, but were generally a consistent offset of about 3-5 MPG - which I attributed to driving habits and conditions).

Interestingly, the one car which had aftermarket fuel economy instrumentation on-board actually got its top MPG at 63 MPG over the course - contrary to the myth of 55 MPH being a gas-saver. Granted, the difference was only in the 1-3 MPG range, but it was higher. Unfortunately, the fuel delivery system was changed in later model years, rendering those fuel flow sensors relatively inaccurate, thus reliable numbers for MPG versus MPH weren't achievable from that instrumentation, but the usual indirect measurements (fuel added versus miles driven) seemed to indicate that peak MPG still fell in the 60+ area for the later models as well.

Dunno whether these observations can be extrapolated as applicable to other makes and models, but I suspect there is at least some similarity.

In my opinion, the Buick 3.8 liter V-6 was a great engine. I had one in a '79 Olds Cutlass that ran with the power of a V-8, but averaged 30 MPG on the highway and around 22 MPG in town. Later, I bought a '97 Riviera with the supercharged 3.8 liter V-6 and it got about the same fuel economy, but with HUGE increase in torque & horsepower, due to the supercharger. Only real weakness I found with that engine was the potential for premature oil pump failure. As long as you knew to rebuild the pump after about 70,000 miles, you were good-to-go.

Regards
Craig