Lean-burning engine... (what vehicles have them?)

[Fingie]

Aren't Lean burn engines designed to be Lean burn, as the top of the cylinder is designed to keep the explosion from touching the walls of the cylinder. Isn't this essentially just running your car on lean

[LeanBurn]

Its too bad the OBD tuner companies can't make a plug and play module for mpgs like they do for power and different octanes.

[Hersbird]

Seems like this would be the best way to add lean burn to a lot of cars.
HPTuners.com >> Performance At Your Fingertips
I wonder what cars have the most unlocked PCMs to do the tuning?
I just got 5.7 Hemi that for a long time Diablo was the only company to have cracked the Chrysler "code". Funny thing is one of the first things offered was the ability to disable the multidisplacement-cylinder deactivation. What! I was wondering why I can't have more of a locked-in MDS setup, you know, so I could run the motor on 4 cylinders with a greater throttle opening and better BSFE. Then add a lean burn mode to that would be awesome. 380hp when you need it, and 4 cylinder lean burn for easing down the highway. Maybe an exhaust diverter to bypass the cat if needed in lean burn. As it stands stock, I am getting pretty good at keeping the engine in "fuel saver" mode (a light in the overhead console) which I assume is the MDS mode. What stinks is the scanguage and my torque app don't work right when in MDS mode (they read way high) so I have to burn a whole tank to figure out the MPG. I still am working on my 2nd tank.