Ya, baddog, the kind of hills where a little more weight might theoretically help would be hills where you would never hit the brakes on the way down. More weight is a sure loser if you are having to press the brakes going down hills.
Bill, I live in Western Maryland and the "hills" I'm talking about, I drive differently than "declines". Coming down a decline I generally put it in neutral and just coast until I either hit a light,traffic, or speed up becuase Im going to slow.
A hill (a mountain if you will, but these are the Appalachins) I may ride the brakes nearly the entire way down or "pulse" the brakes. Otherwise I would gain way too much speed and loose control of the vehicle. But coming up these hills suck soo much gas since they are so steep.
Yes however with a super light car (or a lighter one) you would give it a smaller engine because that would be sufficient for real world needs. Huge engine in small car (as in sports car) would be very fast but if aiming for FE, you'd be at very low throttle most of the time so you'd be far from the sweet spot.
I was talking about weight reduction without changing the engine - most people on here don't change engines.
However, if you did massive weight reduction, and put in a 2 cylinder tiny engine that worked at the best efficiency, it would be better.
__________________ Team GasMisers5 - #1 for first three rounds of the original GS Fuel Economy Challenge
Miles displaced by e-bike since 1 Jan 2008: 62.6 (0 kWh used)
Yugo's had a 2 cyclinder, 1.1 Litre if I remember correctly. They weren't very well designed though and were less powerful than my 1.0 L. Wonder how the FE was though...
They actually had a 45-horsepower 4-cylinder (Yugo 45A), and they were the butt of many jokes in Europe!. They were basically old-design Fiats (can't remember which one), so were very out-of-date. The economy probably wasn't too bad, but they were carburettor. Other 'recycled' Fiat car companies include Lada, and 'FSO' (a polish car company making the 'Polonez Prima'. This was so rubbish that, after 6 years, the body panels would actually rust through and fall off I remember, 15 years ago, I saw a 1988 one on a paper-round I used to do, with duck-tape along the seams of the wings etc, because they had completely rusted through and were about to fall off.
The Fiat 126 BIS had a 2-cylinder engine, and it was light, and very small (so a low frontal area). Cd wouldn't have been that good but CdA probably was. With some aero work it would probably be unbeatable, especially as an electric car.