Why are you talking of something not even related james ?
I've never said manufacturers can't map correctly have I, please show me where ?
Mapping a modded engine is not the same as mapping for a mass produced engine that has to put up with so many variables, if the makers mapping was top notch MSD would have of business, with chips etc, that exploit the less than ideal mapping, oddly enough 92 co incides with cats becoming popular, it was to do with emissions.
What I stated clearly was that a correctly INDIVIDUALLY mapped car will likely show no discernable difference in mpg, mpg and emissions don't always go hand in hand.
Ask stu why the M5 has a ecu that adjusts itself, surely you know more than BMW motorsport, or does this yet AGAIN show there are gains to be had.
tabetha