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Ernie, when you say you worked with kerma to chip your TDI for fuel economy, how did you measured fuel economy when making changes to the ECU maps?
Using vag-com to log fuel consumption, my experience has been that advancing start of injection timing 3 degrees over stock (everything else remaining the same) led to more or less 5% increase in FE.
Tweaking the EGR for max recirculation also lead to an additional 3-5% in FE when combined to a 6 degrees timing advance over stock. When using vag-com or a scangauge to read fuel consumption, increasing EGR will look like fuel consumption went up, because the IQ value was offset upward when you change the EGR rate, which is deceptive, you need to look at tank-to-tank FE. Also, since increased EGR retards the start of combustion event, you need to advance the start of injection timing in order to preserve optimal FE.
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