I originally started looking at this to prevent the CSL software from prematurely protecting the cats since my EGT sensor will be close to the stock US location (installing Megan racing headers). My thinking is that the EGT will read higher which may cause a performance reduction. I have no idea if this would be a big effect (if any at all), and would be interested to hearing from someone that's thought about this already.
So I did a little digging. Searching for TABG (I'm assuming this has to do with EGT) entries in the XDFs from Saildot4K's github gives me the following:
K_TABG_CFG - Turns something on/off?
K_TABG_ERSATZ_OFFSET
K_TABG_ERSATZ_START
K_TABG_ERSATZ_TMOT_OFFSET
K_TABG_DIAG_MIN - This looks like the min range of our EGT sensors (-50 degrees-C)
K_TABG_DIAG_MAX - This looks like the max range of our EGT sensors (1200 degrees-C)
K_TABG_DIAG_SCHWELLE
K_TABG_DIAG_OBERHALB
K_TABG_DIAG_UNTERHALB
K_TABG_DIAG_TIME
K_TABG_TAU - I've always known tau as a time constant, maybe the time constant of the sensor, meaning how long it takes to respond to temp changes. Or maybe an averaging or integration time?
K_TABG_ERSATZ_TAU_F_SLP
K_TABG_ERSATZ_T_F_SLP
K_KATZ_TABG_MIN
K_TI_KATS_TABG_EIN - Has to do with cat protection?
K_TI_KATZ_TABG_SCHNELL - Has to do with cat protection?
K_TI_KATZ_TABG_AUS - Has to do with cat protection?
K_LAS_TABG
K_LSH_TABG_MAX
KL_TABG_ERSATZ_TAU
KL_TABG_ERSATZ_TI
KL_TABG_ERSATZ_TZ
KL_TABG_STAND
KL_TABG_PT200 - I think this converts resistance to an EGT. We use a PT200 EGT sensor, meaning a platinum based sensor that has a resistance of 200 Ohms at 0 degrees-C
KF_TABG_ERSATZ
Comparing Euro and US partials shows differences in these entries:
K_TABG_ERSATZ_START
K_TABG_ERSATZ_TMOT_OFFSET - Has to do with engine temperature
KL_TABG_ERSATZ_TAU - Time constants?
KL_TABG_ERSATZ_TI - Has to do with correcting ignition duration or EGT? (This is also different for CSL.)
KL_TABG_ERSATZ_TZ - Has to do with correcting ignition timing or EGT? (This is also different for CSL.)
KF_TABG_ERSATZ - Table of EGT versus RPM and load (not sure about load)? (This is also different for CSL.)
K_TABG_DIAG_SCHWELLE - Diagnosis threshold? (degrees-C)
K_TABG_DIAG_OBERHALB - Diagnosis above? (degrees-C)
K_TABG_DIAG_UNTERHALB - Diagnosis below? (degrees-C)
K_TABG_DIAG_TIME
KL_TABG_STAND
I think the entries with ERSATZ are used when the DME can't get the EGT data for some reason or another. It will instead use these tables to approximate EGT and other factors. Based on this and KF_TABG_ERSATZ, it seems like BMW expect EGTs for the US tune will read 100-200 degrees-C higher than the Euro tune. The difference is likely due to a combination of the EGT sensor placement (US is closer to engine) and the overall tuning. I guess if you have a tune, the proper way to modify the ERSATZ tables and maps, you'd have to actually measure EGT (maybe AFR and other data). I'm not sure how important this is unless you're extremely tuned and your EGT sensor dies on you.
The biggest difference is in K_TABG_DIAG_OBERHALB (250 Euro/ 1000 US degrees-C) and K_TABG_DIAG_UNTERHALB (150 Euro/ 70 US degrees-C). No clue what these do.
What's interesting is that the entries that I think have to do with cat protection (K_TI_KATS_TABG_) are the same for US and Euro tunes (these values are around 850 degrees-C). I'm assuming one of these is a threshold to start cat protection, maybe not.
If anyone has thought about this before, I'd be interested in hearing your thoughts as to if this is worth pursuing. OR if anyone has info about how the EGT system works and the maps involved, that would be equally as useful.
So I did a little digging. Searching for TABG (I'm assuming this has to do with EGT) entries in the XDFs from Saildot4K's github gives me the following:
K_TABG_CFG - Turns something on/off?
K_TABG_ERSATZ_OFFSET
K_TABG_ERSATZ_START
K_TABG_ERSATZ_TMOT_OFFSET
K_TABG_DIAG_MIN - This looks like the min range of our EGT sensors (-50 degrees-C)
K_TABG_DIAG_MAX - This looks like the max range of our EGT sensors (1200 degrees-C)
K_TABG_DIAG_SCHWELLE
K_TABG_DIAG_OBERHALB
K_TABG_DIAG_UNTERHALB
K_TABG_DIAG_TIME
K_TABG_TAU - I've always known tau as a time constant, maybe the time constant of the sensor, meaning how long it takes to respond to temp changes. Or maybe an averaging or integration time?
K_TABG_ERSATZ_TAU_F_SLP
K_TABG_ERSATZ_T_F_SLP
K_KATZ_TABG_MIN
K_TI_KATS_TABG_EIN - Has to do with cat protection?
K_TI_KATZ_TABG_SCHNELL - Has to do with cat protection?
K_TI_KATZ_TABG_AUS - Has to do with cat protection?
K_LAS_TABG
K_LSH_TABG_MAX
KL_TABG_ERSATZ_TAU
KL_TABG_ERSATZ_TI
KL_TABG_ERSATZ_TZ
KL_TABG_STAND
KL_TABG_PT200 - I think this converts resistance to an EGT. We use a PT200 EGT sensor, meaning a platinum based sensor that has a resistance of 200 Ohms at 0 degrees-C
KF_TABG_ERSATZ
Comparing Euro and US partials shows differences in these entries:
K_TABG_ERSATZ_START
K_TABG_ERSATZ_TMOT_OFFSET - Has to do with engine temperature
KL_TABG_ERSATZ_TAU - Time constants?
KL_TABG_ERSATZ_TI - Has to do with correcting ignition duration or EGT? (This is also different for CSL.)
KL_TABG_ERSATZ_TZ - Has to do with correcting ignition timing or EGT? (This is also different for CSL.)
KF_TABG_ERSATZ - Table of EGT versus RPM and load (not sure about load)? (This is also different for CSL.)
K_TABG_DIAG_SCHWELLE - Diagnosis threshold? (degrees-C)
K_TABG_DIAG_OBERHALB - Diagnosis above? (degrees-C)
K_TABG_DIAG_UNTERHALB - Diagnosis below? (degrees-C)
K_TABG_DIAG_TIME
KL_TABG_STAND
I think the entries with ERSATZ are used when the DME can't get the EGT data for some reason or another. It will instead use these tables to approximate EGT and other factors. Based on this and KF_TABG_ERSATZ, it seems like BMW expect EGTs for the US tune will read 100-200 degrees-C higher than the Euro tune. The difference is likely due to a combination of the EGT sensor placement (US is closer to engine) and the overall tuning. I guess if you have a tune, the proper way to modify the ERSATZ tables and maps, you'd have to actually measure EGT (maybe AFR and other data). I'm not sure how important this is unless you're extremely tuned and your EGT sensor dies on you.
The biggest difference is in K_TABG_DIAG_OBERHALB (250 Euro/ 1000 US degrees-C) and K_TABG_DIAG_UNTERHALB (150 Euro/ 70 US degrees-C). No clue what these do.
What's interesting is that the entries that I think have to do with cat protection (K_TI_KATS_TABG_) are the same for US and Euro tunes (these values are around 850 degrees-C). I'm assuming one of these is a threshold to start cat protection, maybe not.
If anyone has thought about this before, I'd be interested in hearing your thoughts as to if this is worth pursuing. OR if anyone has info about how the EGT system works and the maps involved, that would be equally as useful.