There are several parameters in the MSS6x DMEs which are responsible for the maximum rev limiter. There are also some parameters which define the maximum engine speed at which other engine functions are active. We’ve included the most common parameters under the “Engine Speed” category in ByteTuner. The most commonly tuned parameters are KL_N_BEGR_GANG (rev limiter vs. gear) and the two parameters which control rev limiter vs. the oil temperature (KL_N_BEGR_TOEL_KALT and KL_N_BEGR_TOEL_HEISS). As you’ll see in ByteTuner, there are several other parameters that should also be tuned to fully cover all operational modes and other functions.
Engine idle speed
The engine idle speed can be tuned using the KL_LLR_N_SOLL_TMOT parameter. As with most idle speed control curves, it’s based solely on engine coolant temperature.
Vehicle speed limiter
For the vehicle speed limiter, there are several parameters depending on the chassis configuration (sedan, touring, coupe, or convertible). For simplicity, most tuners tune them all simultaneously regardless of the actual chassis configuration. We also provide access to the limp mode speed limiter and an overall speed limiter.
Cold start delete
The cold start mechanism can be disabled by tuning the K_KH_N_MAX parameter. It needs to be decreased to an engine speed which is slower than the idling speed.
DTC delete
MSS6x DTCs are defined by 26 bytes. Any DTC can be disabled by replacing the stock bytes with zeros.
SAP delete
The SAP (secondary air pump injection) can be disabled by deleting the following DTCs:
- DTC_0x2739: Secondary air mini-HFM electrical diagnostics
- DTC_0x27AF: Secondary air pump
- DTC_0x27B0: Secondary air system throughput - Bank 1
- DTC_0x27B1: Secondary air system throughput - Bank 2
- DTC_0x27B2: Secondary air system throughput main section
- DTC_0x27C5: Secondary air mini-HFM plausibility
If changing the differential ratio, there are couple different parameters that need to be modified depending on the transmission configuration (manual, DTC, or SMG). These can be found under the “Gear Recognition” category in ByteTuner.
Throttle sensitivity
- KF_MD_FAHRER_*
- KF_MD_FAHRER_E2_*
- KF_EGAS_SOLL_AQ
- KF_EGAS_SOLL_AQ_NOTL
For the moment, we only have the servotronic parameters mapped for MSS60. Depending on the active vehicle mode (comfort or sport), there are two parameters available to tune.
Exhaust burble/pops
To successfully tune for exhaust burbles/pops, the goal is to allow the combustion to continue outside of the cylinder and into the exhaust. This is accomplished by delaying the ignition later in the combustion cycle, tuning fuel, and opening the exhaust valves slightly earlier allowing the combustion to escape quicker. All of this tuning should be done in the area of the maps where engine load/filling is low and engine speed is high. This area is where the engine operates after downshifting the transmission with no throttle. You can perform data logs while downshifting to see exactly what engine load/filling and engine speed is of interest.
The easiest way to tune for this can be accomplished using the following parameters:
- KL_LAM_SOLL_VL
- KF_LAM_SOLL_GRUND
- KF_VAN_SOLL_A
- KF_TZ_GRUND
- KF_TZ_MIN
Stage 1 tuning
As with any performance tuning, focus on the core parameters which allow you to add more torque/power and alert the DME that there is more torque: fuel, ignition, airflow, and torque management.
Fuel/lambda
- KL_LAM_SOLL_VL
- KF_LAM_SOLL_GRUND
- KF_TZ_MIN
- KF_TZ_VL
- KF_TZ_GRUND
- KF_VAN_SOLL_A
- KF_VAN_SOLL_E
- K_TAN_OBD_RF_MAX
- KL_MD_RF_MAX_ROH
- KL_MD_RF_MAX_E2
- KF_MD_IND_OPT
- KF_MD_IND_OPT_E2
- KF_MD_ZW_OPT_E2
- KF_MD_KUPP_OFF_E2
For race applications where the primary catalysts are removed, the following DTCs must be deleted:
- DTC_0x2789: Catalytic converter conversion - Bank 1
- DTC_0x278A: Catalytic converter conversion - Bank 2
- DTC_0x272C: Lambda sensor driver diagnostic heating post-cat - Bank 1
- DTC_0x272D: Lambda sensor driver diagnostic heating post-cat - Bank 2