My first three Aston Martins were Lagonda's (1984 series II, 1985 Series III and a 1988 Series IV). I was luck to get 8MPG - on the highway! From that benchmark, the Vantages are OK by me.

 

I agree, but you'll need to go even farther. If 1st gear is really something like 10/1 (as you say, way too "short") then that suggests that simply installing a "taller" final drive ratio would correct the whole gearing situation. It would have to be tall enough to drop the engine down to around 2000 at 80mph, though. You want enough load on the engine at cruise to require a significantly larger throttle opening, which will reduce manifold vacuum/pumping losses. Right now, with the engine spinning at 3000 at 80mph, it's wasting a whole bunch of energy on needless friction and just trying to suck air past that comparatively small throttle opening. In fact, the taller the gearing, the better for fuel economy...short of actually lugging the engine, that is.

Are there other applications that utilize this differential...perhaps offering other final drive ratio choices? I know it seems counter-intuitive to put taller gears into a performance car, but Aston appears to have significantly over-done the gearing in this case...at least for American roads. In Europe, extended cruising may be relatively uncommon, but here? They should've realized...