Never tried to make a custom FFB file, but from what i understand raw should be pure rack FFB, so, based on this
https://docs.google.com/document/d/1sDF6M30kW-XX3Fbiaw_jPvS4M7WEKjLARCwFAgsgiyQ/edit
i'd make something like that (with added road texture):
(Fx_scale 1.0)
(Fy_scale 1.0)
(Fz_scale 1.0)
(My_scale 1.0)
(Mx_scale 1.0)
(Mz_scale 1.0)
# Low Speed Filter Out -------------------------------
(Fx_scale (* Fx_scale (crossover vel_mag 0.0 1.0)))
(Mz_scale (* Mz_scale (crossover vel_mag 0.0 1.0)))
(arm_angle 0.0)
(left_scale (linkage 1.0 -1.0))
(right_scale (linkage 1.0 1.0))
# RACK part starts from here
(Fx_scale 1.0)
(Fy_scale 1.0)
(Fz_scale 1.0)
(My_scale 1.0)
(Mx_scale 1.0)
(Mz_scale 1.0)
# Low Speed Filter Out
(Fx_scale (* Fx_scale (crossover vel_mag 0.0 1.0)))
(Mz_scale (* Mz_scale (crossover vel_mag 0.0 1.0)))
# Texture --------------------------------------------
(road_scale (* 0.0005 1.0))
(brk_scale 0.0)
(bump_scale (* 0.24 1.0))
(scrub_scale (* 14.0 1.0))
(tex_k 20000.0)
(tex_d 1.0)
(FL_tex (+ (* road_scale FL_road) (* brk_scale FL_brk) (* bump_scale FL_bump) (* scrub_scale FL_scrub)))
(FL_tex (split FL_tex 0.0 1.0 1.0 2.0 0.01))
(FL_tex (spring FL_tex tex_k tex_d 1.0))
(FR_tex (+ (* road_scale FR_road) (* brk_scale FR_brk) (* bump_scale FR_bump) (* scrub_scale FR_scrub)))
(FR_tex (split FR_tex 0.0 1.0 1.0 2.0 0.01))
(FR_tex (spring FR_tex tex_k tex_d 1.0))
(tex (+ FL_tex FR_tex))
(tex (soft_clip tex 1.0 0.0))
# Scaler as informational only, doesnt affect output -
(scale_window_init 10.0)
(scale_window_nominal 2.0)
(scale_soft_clear_t 10.0)
(scale_min 0.2)
(scale_max 2.0)
(scale_blend_t 2.0)
(signal_scale output
1.0 1.0 1.0 1.0 1.0
0.0
0.0 0.0)
(output (tighten output 0.08 0.030)) # Deadzone Removal deadzone and falloff values as PCars1, specifit for T300. Remove/edit if you're using other wheel.
(output (relative output 1.12 0.45 1.0)) # Relative Output Gain, Bleed and Clamp values as PCars1, specific for T300. Remove/edit if you're using other wheel.
(output (+ (* volume output) (* feel fx)))
(histogram output)
(output (hard_clip (* output gain) 1.0))
#end
Try this if you will, but i don't guarantee it'll work, i just removed the tire forces from the linked custom FFB