[ever_green]

Hi i'm a tuner that mostly deals with Subarus and Mitsubishis powerplants. From Naturally Aspirated to Turbocharged, My customers independent of how much power they make always monitor their fuel economy. So it's important for me to give them best possible mileage on the streets. One possible area is for the automatic folks to have the drivebywire and transmission tuned in a way that will short shift and keep the throttle open wider (and sooner). This sometimes can lead to open loop enrichment (although it does not always occur, but if it does the ratios will be about 5% more rich). So with this low RPM high MAP tune the engine will usually shift around 2000-2700 RPM and keep 13 psi of MAP (roughly 90% engine relative load as referred to here).

In contrast the DBW & Transmission can be tuned to shift about 500 RPM higher but with lower MAP of about 11-12 PSI (75% Load). However chances of hitting open loop enrichment is much smaller this way, so you spend more time running as lean as possible.

Several things:
- This tune does Not affect cruising efficiency, it's just for acceleration
- Peak VE on these cars is usually around 4000 RPM
- Closed loop target AFR is roughly 14.5:1
- BSFC sweet spot is at very high MAP and wide RPM range according to manufacturers, yet i'm not sure this is trustworthy as they usually overestimated the 'boundaries'

I think I should go with Higher MAP, open thorttle, lower RPM strategy despite chances of enrichment (up to 5%) ?