Hi obioban -
I'd love to see controlled as possible testing at lower constant speeds. I'd bet a dollar fuel economy will improve as speed drops, right down to just above lugging RPM.
(Feel free to post a couple of "filler" posts to get full forum permissions. It's there so we can spot spammers and obviously you're not one.)
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Since posting this thread originally, I had a chance to take a 6-speed, 505 hp Corvette Z06 out to collect info for a speed vs. MPG chart:
http://ecomodder.com/forum/showthrea...05-a-9841.html
In a nutshell, the slower, the better.