No really, I can't figure it out.

I think SUMODE defines the values corresponding to possible configurations of flaps in the intake. These flaps modify the intake's effective length and resonance. In theory, when you have a boxster or V engine, you can take advantage of one side's pressure wave to improve filling of the opposite side. At least, this is what Porsche (for example) claims.

So, if you have two flaps in the intake, the possible configurations are:


Note that I could be entirely wrong on this. On the other hand, I have changed my KFSU* maps to open the flaps at different RPM's - using values defined in SUMODE* maps, so it checks out.

You are welcome! I don't know about the 2.7t though. If there are no flaps then SUMODE probably does not apply. Unless, they use it to control a solenoid for something else?

I don't have the file handy but I remember that in my ME7.8, the possible SUMODE values are defined in maps named with the prefix SUMODE. If you find these maps and they contain only zeroes then it is almost certain that SUMODE does not apply for the 2.7t.