Was about to ask in the 987-MAF-thread, but to avoid destroying that thread I make a separate one. I´m trying to get my head around how the Motronic 7.8 actually works. And, I really feel kind of stupid, I´m sure I got some major parts wrong.. But here we go.
1) ADAPTION
I take it that the DME adapts to a certain amount of change in airflow after a improvment of intake or exhaust. This "adaption" is that reffering to the adjustment of fuel-input that is made by the short term fuel trim and after a while moves over to long term fuel trim? Or is it the actual fuelmaps that changes by some kind of magic?
2) MAF CALCULATIONS
As discussed in other threads, when using the 987 MAF-tube the DME doesnt know of the larger area of the 987-tube and calculates to little airflow leading to a lean state. If I have understood this correctly a pro tuner will be able to adjust this in the DME. How is this done? Is it a simple constant in the DME-calculation that is adjusted to represent the new area or are the whole fuelmaps adjusted?
3) MAPS
A very wild guess is that there are three states of operation:
a) Startup/Idling: I would guess that this is managed by a fixed map in a open loop condition.
b) "Middle ground/half throttle" I guess there is ONE singel fuelmap covering this area operating in "Closed loop" thus adjusting STFT/LTFT based upon feedback from the o2-sensors.
c) WOT (Driving like a man) I guess this is covered by a separate fuelmap operating in open loop.
d) Finally I guess that also the ignition is managed by separate maps just like the fuel.
4) CODE/PASSWORD
Is there a password to get into the Motronic that we need to get from the dealer? Then how do the pro tuners do? I have got an offer to tune my car and I don´t think they need a code from the dealer.
Just trying to learn, this is so interesting! Please feel free to tell me where I´m wrong above, or just guess together..
