Quote Originally Posted by EagleMark View Post
Les TPS would be good.

I corrected my staement above:
I would agree with you if you are holding air/fuel ratio as a constant, however you want a balancing act. You want to create as much torque as possible from a specific air/fuel charge, but you also want to minimize pumping losses at the same time. Over the years of tuning I have found that slightly retarding the timing as the MAP decreases and rpm rises helps keep you in a MPG sweet spot. For example in most of my tunes, my 50-60 KPA @ 2,000 rpm timing will be higher than my 20-40 KPA at the same RPM.