I have a little tuning session to show you.
I don't believe this can be called Betaflight 4.0. A lot of features can still be changed or added, and there are still some improvement to come for the features already there.
I love the new Dynamic Lowpass Filters added, and with the improved Dynamic Notch Filter, the developers have made, what seem to me, the perfect default filters. Dont want to tune. Just go fly the defaults.
I raised the D-term Filters, and saw an improvement. Raising filters, gives less delay from the gyro to the pid controller, giving a more direct feel, and better propwash handling. In turn, you are more prone to burn up your motors whith a bent or broken prop.
After that, I raised D-term on roll and pitch. If you follow my example
CHECK FOR HOT MOTORS AT EVERY STEP.
Dont blame me if you burn up your setup.
Last note: Later i tried raising D-term from 26 to 36, but started hearing thrilling oscillations, suggesting D-term being too high. I lowered back down to 26, and might even lower back down to 16 in near future. Could try raising Gyro Lowpass Filter 1 from 150 Hz.
-: The tune I ended up with :-
set dyn_lpf_dterm_min_hz = 120
set dyn_lpf_dterm_max_hz = 180
set dterm_lowpass_type = BIQUAD
set dterm_lowpass_hz = 200
set dterm_lowpass2_type = BIQUAD
set dterm_lowpass2_hz = 200
set dterm_notch_hz = 0
set gyro_lowpass_type = BIQUAD
set gyro_lowpass_hz = 150
set dyn_lpf_gyro_min_hz = 150
set dyn_lpf_gyro_max_hz = 500
set gyro_lowpass2_type = PT1
set gyro_lowpass2_hz = 0
set gyro_notch1_hz = 0
set gyro_notch1_cutoff = 0
set gyro_notch2_hz = 0
set gyro_notch2_cutoff = 0
set dyn_notch_range = AUTO
set dyn_notch_width_percent = 8
set dyn_notch_q = 120
set dyn_notch_min_hz = 150
set p_pitch = 50
set i_pitch = 85
set d_pitch = 26
set f_pitch = 150
set p_roll = 50
set i_roll = 78
set d_roll = 26
set f_roll = 150
set p_yaw = 10
set i_yaw = 130
set d_yaw = 0
set f_yaw = 100
set tpa_rate = 50
set tpa_breakpoint = 1500
set tpa_mode = D
This is not a new build, but have some fairly good motors. What seems to do the trick of having cool motors are the new filters and the flight controller having an mpu6000 gyro.