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lowside67 · 08-20-2016, 07:48 PM

Eliminating e-Diff & Other Nannies

I am going to completely ignore the elephant in the room that it's been an embarrassingly long time since I've updated this thread. It's been a busy year and unfortunately not with autocross, or really the car at all. But now that work is calming down a little, I am making some efforts to get back to this and deal with some of the things that have been frustrating me about this otherwise great little car.

As you likely know, the 1 series (along with most every modern BMW) has an electronic differential, which basically means that when it detects a wheel slipping, it simple applies the brakes selectively to that wheel. This works just fine on the street but is not a desirable characteristic on a track or autocross course - it's hard on your rear brakes, makes the car unpredictable, and generally is inferior to a mechanical differential..

Most people who have installed an LSD have reported that they have no issues with interactions between the new mechanical LSD and the stock e-diff. I am not one of those people, my car feels like a civil war is being fought between the incumbent e-diff and new mechanical LSD. Specifically, at autocross with DSC fully disabled by the 3 second push, you can absolutely feel the brakes / ediff fighting aggressively. It has incredibly loud vibration / noise when applying power out of a turn in a traction limited situation.

I have been doing lots of reading, and today I took the plunge and had my car recoded to eliminate the e-diff (along with a few other things while I was in there). Guide to electronic nannies and how to code them off and a few other threads here and on E90post have been invaluable to learning which modules/codes need to be tweaked.

Here are the 4 I recoded from the DSC module (descriptions blatantly stolen from the excellent "Paradoxical" guide linked above):

DIFF_LOCK
This is the actual electronic differential - ie the automatic application of one wheel braking to whichever rear wheel is detected to be slipping under throttle application.

FLR ("Engine Power Reduction to Prevent Brake Disc Overheating")
This is the worst of them all. Modern BMWs will actively cut the throttle in the middle of your track day if it has reason to believe that your brake pads are overheating. Normally, this wouldn't be such a bad thing - nobody wants to crash into ARMCO going 140mph. The problem is, your BMW doesn't actually have temperature sensors anywhere in the braking system. The computer relies on a "calculated" brake disc temperature based on several inputs including ground speed, brake pedal application force, and the frequency with which the electronic differential applies "torque-vectoring" braking. Your BMW has no way to know that you installed a Stoptech Big Brake Kit with Castrol SRF fluid and Performance Friction PFC01 pads. It just assumes you are running the stock system and cuts your throttle based on values that would overheat the OEM brake pads.

FBS ("Brake Fading Compensation")
Brake fade compensation "calculates" the temperature of your brake fluid. The higher the calculated temperature of your brake fluid (remember, there is no real sensor), the more hydraulic assist will be added to your brake pedal. In theory, this masks brake fade on the street. On the track, it makes a consistent brake pedal literally impossible.

BB_RAB ("Brake Standby")
This is another ridiculous feature that works well on the road, but terribly on track. If your car detects an aggressive throttle lift-off, it will pre-tension the brakes in anticipation of a hard braking maneuver. This would actually be great if it wasn't for what it does next - if you don't brake within 8 seconds of throttle lift-off, it un-tensions the brakes. I have a theory that people who think they are experiencing pad knock-back on the track are actually just being victimized by this "feature." Turn it off for a more consistent brake pedal that responds predictably.

Here are the actual values I have changed these to:

Code:

Codes changed in DSC module: (these are the "after" values)

C0F_DIFF_LOCK
	wert_00
	wert_01
C0F_FBS
	wert_00
C0F_FLR
	wert_00
	wert_02
C0F_BB_RAB
	wert_00

Code:

Stock TRC file for 2011 BMW 128i (Canadian edition, 07/10 build date) DSC module:

SZL
	wert_02
C0X_C8
	wert_02
C0F_AFH_HSA
	wert_01
C0F_AFS
	wert_00
C0F_ASC_AMR_STB
	wert_03
C0F_ASC_BMR_STB
	wert_02
C0F_ASL
	wert_00
C0F_BAUART
	wert_02
C0F_BB_RAB
	wert_01
C0F_BBV
	wert_00
C0F_BBV_KORR_HA
	wert_00
	wert_03
C0F_BBV_KORR_VA
	wert_04
C0F_BERGAB_GERASTET
	wert_00
	wert_01
C0F_BERGAB_KENNEN
	wert_00
	wert_01
C0F_BERGABANSATZ
	wert_00
C0F_BTM
	wert_00
C0F_CBC
	wert_00
C0F_CF_ESM_HB
	wert_00
	wert_01
C0F_CF_ESM_LB
	wert_00
	wert_01
C0F_CR_ESM_HB
	wert_00
	wert_01
C0F_CR_ESM_LB
	wert_00
	wert_01
C0F_DBC_MIN_AUSLOESEDRUCK
	wert_00
C0F_DCC_C_AAT
	wert_00
C0F_DCC_C_ATT_SCHUB_AUS
	wert_00
C0F_DCC_C_ATT_SCHUB_EIN
	wert_00
C0F_DCC_DTC
	wert_00
C0F_DELTA_PSI_BETA_LIMIT
	wert_01
C0F_DF_DIR
	wert_02
C0F_DIFF_LOCK
	wert_02
C0F_DRUCKMODELL_HA
	wert_02
C0F_DRUCKMODELL_VA
	wert_02
C0F_ECBA_DCC
	wert_00
C0F_FBS
	wert_01
C0F_FLR
	wert_01
C0F_GETRIEBE
	wert_00
C0F_GMB
	wert_00
C0F_GMK_ECBA_HA
	wert_01
C0F_GMK_ECBA_VA
	wert_03
C0F_GMR_MAX_LIMIT_SCHRAEG
	wert_00
C0F_GMR_MIN_LIMIT_SCHRAEG
	wert_00
C0F_HSA
	wert_02
C0F_HSA_AFH_AFU
	wert_00
C0F_IPM_MAX_P_RES
	wert_00
C0F_KUEHLSCHACHT
	wert_02
C0F_LCL
	wert_00
C0F_LENKWINKELKENNLINIE
	wert_03
C0F_LF_ESM
	wert_00
	wert_01
C0F_LR_ESM
	wert_00
	wert_01
C0F_LUEFTER
	wert_00
C0F_LWK_X2
	wert_00
	wert_01
C0F_LWK_X3
	wert_00
	wert_01
C0F_LWK_X4
	wert_00
	wert_01
C0F_LWK_Y1
	wert_00
	wert_01
C0F_LWK_Y2
	wert_00
	wert_01
C0F_LWK_Y3
	wert_00
	wert_01
C0F_LWK_Y4
	wert_00
	wert_01
C0F_M_ESM
	wert_00
	wert_01
C0F_MIN_DRUCKAUFBAU_GRAD
	wert_00
C0F_MOTOR
	wert_05
C0F_MOTOR_LEISTUNG_MAX
	wert_00
	wert_18
C0F_MOTOR_SCHLEPP_P
	wert_00
	wert_01
C0F_PRE_MSR
	wert_00
C0F_PRE_USC
	wert_00
C0F_RPA
	wert_00
C0F_RPA_SCHWELLE
	wert_01
C0F_SC_X_ESM
	wert_00
	wert_01
C0F_SC_Y_ESM
	wert_00
	wert_01
C0F_SCHUBABSCHALTUNG
	wert_00
C0F_SDR_CTC
	wert_00
C0F_SETZ_V_MAX
	wert_00
C0F_SPURWEITE
	wert_00
	wert_01
C0F_SST
	wert_00
C0F_TB_BDD
	wert_01
C0F_THETA_ESM
	wert_00
	wert_01
C0F_UEBERSTEUERN_MUE_0
	wert_03
C0F_UEBERSTEUERN_MUE_1_2
	wert_03
C0F_UNTERSTEUERN_MUE_0
	wert_00
C0F_UNTERSTEUERN_MUE_1_2
	wert_00
C0F_UNTERSTEUERSCHWELLE
	wert_00
	wert_02
C0F_V_EINHEIT
	wert_00
C0F_VERZOEG_NEG_FEIN
	wert_00
C0F_VERZOEG_NEG_GROB
	wert_00
C0F_VERZOEG_POS_FEIN
	wert_00
C0F_VERZOEG_POS_GROB
	wert_00

08-20-2016, 07:48 PM	#46
lowside67 First Lieutenant 219 Rep 361 Posts Drives: 2011 BMW 128i Join Date: Apr 2015 Location: Vancouver, Canada iTrader: (0)	Eliminating e-Diff & Other Nannies I am going to completely ignore the elephant in the room that it's been an embarrassingly long time since I've updated this thread. It's been a busy year and unfortunately not with autocross, or really the car at all. But now that work is calming down a little, I am making some efforts to get back to this and deal with some of the things that have been frustrating me about this otherwise great little car. As you likely know, the 1 series (along with most every modern BMW) has an electronic differential, which basically means that when it detects a wheel slipping, it simple applies the brakes selectively to that wheel. This works just fine on the street but is not a desirable characteristic on a track or autocross course - it's hard on your rear brakes, makes the car unpredictable, and generally is inferior to a mechanical differential.. Most people who have installed an LSD have reported that they have no issues with interactions between the new mechanical LSD and the stock e-diff. I am not one of those people, my car feels like a civil war is being fought between the incumbent e-diff and new mechanical LSD. Specifically, at autocross with DSC fully disabled by the 3 second push, you can absolutely feel the brakes / ediff fighting aggressively. It has incredibly loud vibration / noise when applying power out of a turn in a traction limited situation. I have been doing lots of reading, and today I took the plunge and had my car recoded to eliminate the e-diff (along with a few other things while I was in there). Guide to electronic nannies and how to code them off and a few other threads here and on E90post have been invaluable to learning which modules/codes need to be tweaked. Here are the 4 I recoded from the DSC module (descriptions blatantly stolen from the excellent "Paradoxical" guide linked above): DIFF_LOCK This is the actual electronic differential - ie the automatic application of one wheel braking to whichever rear wheel is detected to be slipping under throttle application. FLR ("Engine Power Reduction to Prevent Brake Disc Overheating") This is the worst of them all. Modern BMWs will actively cut the throttle in the middle of your track day if it has reason to believe that your brake pads are overheating. Normally, this wouldn't be such a bad thing - nobody wants to crash into ARMCO going 140mph. The problem is, your BMW doesn't actually have temperature sensors anywhere in the braking system. The computer relies on a "calculated" brake disc temperature based on several inputs including ground speed, brake pedal application force, and the frequency with which the electronic differential applies "torque-vectoring" braking. Your BMW has no way to know that you installed a Stoptech Big Brake Kit with Castrol SRF fluid and Performance Friction PFC01 pads. It just assumes you are running the stock system and cuts your throttle based on values that would overheat the OEM brake pads. FBS ("Brake Fading Compensation") Brake fade compensation "calculates" the temperature of your brake fluid. The higher the calculated temperature of your brake fluid (remember, there is no real sensor), the more hydraulic assist will be added to your brake pedal. In theory, this masks brake fade on the street. On the track, it makes a consistent brake pedal literally impossible. BB_RAB ("Brake Standby") This is another ridiculous feature that works well on the road, but terribly on track. If your car detects an aggressive throttle lift-off, it will pre-tension the brakes in anticipation of a hard braking maneuver. This would actually be great if it wasn't for what it does next - if you don't brake within 8 seconds of throttle lift-off, it un-tensions the brakes. I have a theory that people who think they are experiencing pad knock-back on the track are actually just being victimized by this "feature." Turn it off for a more consistent brake pedal that responds predictably. Here are the actual values I have changed these to: Code: Codes changed in DSC module: (these are the "after" values) C0F_DIFF_LOCK wert_00 wert_01 C0F_FBS wert_00 C0F_FLR wert_00 wert_02 C0F_BB_RAB wert_00 Code: Stock TRC file for 2011 BMW 128i (Canadian edition, 07/10 build date) DSC module: SZL wert_02 C0X_C8 wert_02 C0F_AFH_HSA wert_01 C0F_AFS wert_00 C0F_ASC_AMR_STB wert_03 C0F_ASC_BMR_STB wert_02 C0F_ASL wert_00 C0F_BAUART wert_02 C0F_BB_RAB wert_01 C0F_BBV wert_00 C0F_BBV_KORR_HA wert_00 wert_03 C0F_BBV_KORR_VA wert_04 C0F_BERGAB_GERASTET wert_00 wert_01 C0F_BERGAB_KENNEN wert_00 wert_01 C0F_BERGABANSATZ wert_00 C0F_BTM wert_00 C0F_CBC wert_00 C0F_CF_ESM_HB wert_00 wert_01 C0F_CF_ESM_LB wert_00 wert_01 C0F_CR_ESM_HB wert_00 wert_01 C0F_CR_ESM_LB wert_00 wert_01 C0F_DBC_MIN_AUSLOESEDRUCK wert_00 C0F_DCC_C_AAT wert_00 C0F_DCC_C_ATT_SCHUB_AUS wert_00 C0F_DCC_C_ATT_SCHUB_EIN wert_00 C0F_DCC_DTC wert_00 C0F_DELTA_PSI_BETA_LIMIT wert_01 C0F_DF_DIR wert_02 C0F_DIFF_LOCK wert_02 C0F_DRUCKMODELL_HA wert_02 C0F_DRUCKMODELL_VA wert_02 C0F_ECBA_DCC wert_00 C0F_FBS wert_01 C0F_FLR wert_01 C0F_GETRIEBE wert_00 C0F_GMB wert_00 C0F_GMK_ECBA_HA wert_01 C0F_GMK_ECBA_VA wert_03 C0F_GMR_MAX_LIMIT_SCHRAEG wert_00 C0F_GMR_MIN_LIMIT_SCHRAEG wert_00 C0F_HSA wert_02 C0F_HSA_AFH_AFU wert_00 C0F_IPM_MAX_P_RES wert_00 C0F_KUEHLSCHACHT wert_02 C0F_LCL wert_00 C0F_LENKWINKELKENNLINIE wert_03 C0F_LF_ESM wert_00 wert_01 C0F_LR_ESM wert_00 wert_01 C0F_LUEFTER wert_00 C0F_LWK_X2 wert_00 wert_01 C0F_LWK_X3 wert_00 wert_01 C0F_LWK_X4 wert_00 wert_01 C0F_LWK_Y1 wert_00 wert_01 C0F_LWK_Y2 wert_00 wert_01 C0F_LWK_Y3 wert_00 wert_01 C0F_LWK_Y4 wert_00 wert_01 C0F_M_ESM wert_00 wert_01 C0F_MIN_DRUCKAUFBAU_GRAD wert_00 C0F_MOTOR wert_05 C0F_MOTOR_LEISTUNG_MAX wert_00 wert_18 C0F_MOTOR_SCHLEPP_P wert_00 wert_01 C0F_PRE_MSR wert_00 C0F_PRE_USC wert_00 C0F_RPA wert_00 C0F_RPA_SCHWELLE wert_01 C0F_SC_X_ESM wert_00 wert_01 C0F_SC_Y_ESM wert_00 wert_01 C0F_SCHUBABSCHALTUNG wert_00 C0F_SDR_CTC wert_00 C0F_SETZ_V_MAX wert_00 C0F_SPURWEITE wert_00 wert_01 C0F_SST wert_00 C0F_TB_BDD wert_01 C0F_THETA_ESM wert_00 wert_01 C0F_UEBERSTEUERN_MUE_0 wert_03 C0F_UEBERSTEUERN_MUE_1_2 wert_03 C0F_UNTERSTEUERN_MUE_0 wert_00 C0F_UNTERSTEUERN_MUE_1_2 wert_00 C0F_UNTERSTEUERSCHWELLE wert_00 wert_02 C0F_V_EINHEIT wert_00 C0F_VERZOEG_NEG_FEIN wert_00 C0F_VERZOEG_NEG_GROB wert_00 C0F_VERZOEG_POS_FEIN wert_00 C0F_VERZOEG_POS_GROB wert_00 __________________ 2011 BMW 128i - Check out my STX build thread! Last edited by lowside67; 08-21-2016 at 04:09 PM..
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