[elhigh]

RE: The Top Gear cars: let me remind you they use English gallons, which are considerably larger than American gallons. So their economy is impressive, yes, but a tad less so.

I have one tank on my own car that went over 740 miles, and a few more that have broken 700.

I have grumbled about that Opel many times. It was designed to do one thing and is utterly worthless for anything else, except inspiring wild-eyed believers. The one thing it really points up, at least to me, is that slowing down and never stopping are two of the best things you can do for your fuel economy.

I think that's an experiment that should be re-performed but with EFI. Get it warm and lean the snot out of it for the record run. Do all the throttling via injector duty cycles instead of relying on an ultra-tiny carburetor, eliminate that pesky pumping loss from the too-small intake. I'd be curious to see how much better, with modern sensors and controls, that same car could do than the old, analog version.

To further your own line of inquiry, Rich, try it with conventional, insulated and heated intakes for maximum fuel vaporization. That could prove informative. The vehicle as a testbed is already there, putting it back to work to further explore what works for fuel economy isn't a bad idea.

This is all blue-skying of course.