[aerohead]

Fabio,sounds like a juicy project,here's some miscellaneous data :

The original 1984 CRX had frontal area 1.718 meter square,and Cd 0.35,for a drag factor of 0.601 meter square.This car,with the 60 Bhp 1.3-liter engine achieved 52 mpg at a steady 55-mph.When I streamlined mine down to Cd 0.23,that pushed the drag factor ( CdA ) down to 0.395 meter square,and mpg improved to 60.6 mpg at the same 55 mph.On it's best day she got 74.8 mpg at the same speed.

When the Insight came out in 2000,it had Frontal area 1.9 meter square,Cd 0.25,for CdA 0.475 meter square and 27-Bhp engine,and at around 55 mph,could be expected to return 60 mpg,with the M-5 transmission.

Without the electric motor assist,the Insight has as much power as a 1967 Volkswagen Beetle,with it's engine sawed in half.While operating at close to WOT on the highway,the Insight achieves very high BSFC,but without the electric motor to get it up to speed,it would be dangerous to operate on the highway.

The Honda VX powertrain would provide all the power you'd need.Those cars could do mid-fifties mpg stock,so with the better Cd of the Insight she should be able to return mpg in the neighborhood of the original Insight,but only on the open road.In city traffic,without the hybrid drive,she'd be no better than the VX was.Perhaps 40 mpg.