Motronic Adaptation?
11-21-2011, 10:17 PM
#1
Three Wheelin'
Thread Starter
Motronic Adaptation?
We all know that the Motronic will target a 14.7 AFR in the OT throttle maps using an algorithm based on input from the NBO2 sensor. The cycle time for this appears to be 0.75 seconds based on the data I have logged (ie every 0.75s it adjusts the fuel, rechecks lambda and repeats until 14.7 is achieved). These values are stored in the RAM. This is of course closed loop control.
But, does the Motronic apply any other adaptive algorithms to take into account wear and tear on the engine for open loop control? ie - do any of the trim settings applied to get 14.7 at part throttle get applied to the WOT fuel values, or is the trim only applied to the PT maps (where in closed loop).
Secondly, I thought I had found the trigger points (RPM and load) for going from closed to open loop in the code for PT, but the DME still targets 14.7 at all RPMs. Remember that I am talking about a S2 here. In additional the lambda rich/lean adjustment maps only go to 4000rpm, yet the DME still seeks 14.7 above 4000rpm (tested up to 5000).
If I can't get my tune right in the PT maps, are there any likely probelms with running the cat delete mode so I can tune to richer AFRs above say 4000 rpm?
But, does the Motronic apply any other adaptive algorithms to take into account wear and tear on the engine for open loop control? ie - do any of the trim settings applied to get 14.7 at part throttle get applied to the WOT fuel values, or is the trim only applied to the PT maps (where in closed loop).
Secondly, I thought I had found the trigger points (RPM and load) for going from closed to open loop in the code for PT, but the DME still targets 14.7 at all RPMs. Remember that I am talking about a S2 here. In additional the lambda rich/lean adjustment maps only go to 4000rpm, yet the DME still seeks 14.7 above 4000rpm (tested up to 5000).
If I can't get my tune right in the PT maps, are there any likely probelms with running the cat delete mode so I can tune to richer AFRs above say 4000 rpm?
11-21-2011, 10:50 PM
#2
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Have you looked at this site? Lots of good info on closed and open loop.
http://the944.com/
One thing I ran into in the amp area that may help:
M2.10.1 only: I found that Porsche 968 and 993 has a code that marks the end of the map table. Doing a search for C40A finds the end of the map table. I only find this in M2.10.1 Motronic.
http://the944.com/
One thing I ran into in the amp area that may help:
M2.10.1 only: I found that Porsche 968 and 993 has a code that marks the end of the map table. Doing a search for C40A finds the end of the map table. I only find this in M2.10.1 Motronic.
11-22-2011, 01:16 AM
#3
Three Wheelin'
Thread Starter
Thanks Brian - yes I had seen that. I understand the lambda control principles, my query is around how this information is used for other than the PT fuel maps and around issues running open loop all the time and identifying closed loop limits in the code.
11-26-2011, 03:48 AM
#5
Three Wheelin'
Thread Starter
Mike,
Yep - running ROW settings. I have figured out all the maps in the DME and how both the coding and variant plugs affect map selection. There are four possible settings:
No variant plug
CA/JA/AU variant plug
Reversed variant plug (outer pins on variant plug switched) (this is not a normal setting - ie no cars actually had this map set) Also - only affect WOT timing.
"No cat" coding plug (overrides variant switch)
PT fuel is the same for all except when the "no cat" plug is bridged
PT ignition - 3 maps - AU/CA/JA (region coding), ROW, and "no cat"
WOT fuel - Au/CA/JA and ROW use same map, separate map for "no cat"
WOT timing - AU/CA/JA and Row use same map, flipping the wire on the 3 pin variant plug switches to a separate map (timing retarded by about 3-4 degrees), "no cat" has separate map. This map could be used as a "race" map if you had access to higher octane fuel.
I have wires running to both the variant and "no cat" plugs so I can swap. Might run a "no cat" map on the track, depending on how tuning goes.
Yep - running ROW settings. I have figured out all the maps in the DME and how both the coding and variant plugs affect map selection. There are four possible settings:
No variant plug
CA/JA/AU variant plug
Reversed variant plug (outer pins on variant plug switched) (this is not a normal setting - ie no cars actually had this map set) Also - only affect WOT timing.
"No cat" coding plug (overrides variant switch)
PT fuel is the same for all except when the "no cat" plug is bridged
PT ignition - 3 maps - AU/CA/JA (region coding), ROW, and "no cat"
WOT fuel - Au/CA/JA and ROW use same map, separate map for "no cat"
WOT timing - AU/CA/JA and Row use same map, flipping the wire on the 3 pin variant plug switches to a separate map (timing retarded by about 3-4 degrees), "no cat" has separate map. This map could be used as a "race" map if you had access to higher octane fuel.
I have wires running to both the variant and "no cat" plugs so I can swap. Might run a "no cat" map on the track, depending on how tuning goes.
