Neg89 was asking for e89 z4 which I believe has bosch? DSC and uses DSC_89.Cxx.? Hence why I asked for coding index. But it obviously won't work with 1M/M3 firmware.either disable pre_usc coding in dsc or switch to 1m/m3 dsc firmware
With e8/9x mk60e5 you can correct this without converting to 1M/M3 firmware…
By coding it to use, and with a custom Lenkwinkel Kenlinnie (LWK)...
You need to set C0x_LENKWINKELKENNLINIE - STEERING ANGLE CHARACTERISTIC CURVE (address 0x30000D mask 0x07) to 0x01 which tells it to use a custom LWK.
The custom LWK is coded with C0x_LWK_X2, X3, X4, Y1, Y2, Y3, Y4 (address's 0x300029 to 0x30002F).
The x-axis is steering wheel angle [DEG=DATA] with X1=0degrees
The y-axis is steering ratio [RATIO:1=DATA/10]
To interpolate the values the correct method is described in patent DE10336046A1.
But you can get good results just using more normal forms of interpolation.
You will want to map this to your specific setup as it will vary with differing alignments and suspension components etc. because of the double jointed swivel bearing setup, using turn tables or similar device for measuring the steered angle of each front wheel at the reported steering wheel angle then calculate the mean steered angle (the vehicle model in use is a single track/bicycle model (einspumodell (ESM))) and then calculate the ratio for it at the steering wheel angles you have mapped.
This works for both e8/9x non-m & 1M/M3
This can then be used (as BMW does) to tune the system between oversteer & understeer...