Wow. I never drove my Corvette (on the hwy) between 40-60 -- for a LONG stretch. The only speed where I've measured MPG is 70. And, it was in the 30mpg range -- sixth gear.

About the slowest I'd drive in 6th w/o lugging is 60 -- even then steep uphills would require 5th. So, I'm not sure the same approximation applies to the vette. (If so, It must get well over 30mpg in reality.)

That vacuum idea is very good. Not sure how cheap/easy -- but good. OTOH, gut instinct had already told me much over 2k rpms would cause a drop in MPG.

The other issue (and part of the point of this thread), is whether the power option actually improves MPG (vs normal mode) for larger diameter tires -- especially for city driving.

:cheers: