Point of comparison for my Metro/Firefly's fuel consumption performance against the Insight...
On a 293 (182 mi.) weekend round trip, identical route, nearly identical conditions:
- Insight: 2.5L / 100 km or 94 mpg (US): last fall, with IMA disabled and 5 aero mods in place, cruising within +/- a couple of km/h of the posted limit of 80 km/h / 50 mph on the open road.
Main techniques used: DWL (driving with load), aiming to stay in lean burn at 100 MPG on the instant display on the highway at 50 mph / 80 km/h. Manual engine-off to most stops/turns, DRL used selectively (on in the city).
- EcoModded Metro/Firefly: 3.4 L/100 km or 69.4 mpg (US): this weekend.
Main techniques used: same as the Insight, except no lean burn (!), so to achieve that fuel economy, I had to drive 10 km/h slower on the open road compared to the Insight (where I could, without pissing off other drivers)!
Conditions on both trips were nearly perfect: mostly flat roads, dry, 15-20*C (cool enough to comfortably keep the windows up on the highway), little to no wind on both days, very light traffic outside of the city.