so anyway this has been bugging me for like two weeks. swapped from HQ 5x4.3x3 to Gemfan 51466 on my freestyle quad and now the whole feel is just wrong. its not oscillating badly or anything obvious like that, its more like the quad feels sluggish on quick direction changes and theres this kind of mushy feeling on the roll axis especially. pitch feels mostly fine.

running a F405 with the Aikon AK32 35A ESCs and currently on RPM filter with BIlateral telemetry working, checked that. motors are 2207 1950kv on 4S. before anyone asks i already reran the notch filters and nothing changed. not sure if this is a P gain thing or D gain thing or if maybe i just need to increase master multiplier. or maybe its the props and they just dont suit the tune at all

any ideas where to start without doing a full retune from scratch because honestly the previous tune was dialed pretty well for the HQs

Gemfan 51466s have noticeably more grip than HQs so youll probably need to bump D a bit to keep up with the extra authority, especially on roll. the mushy feeling is usually low P or D not keeping up with the prop response. id start by pushing D term up like 10-15% on roll axis only and see if that firms it up before touching anything else. master multiplier is a blunter tool and might make pitch feel weird if you crank it without accounting for the axis difference.

also double check your filtering isnt being too aggressive now, stiffer props can change your noise profile and sometimes what was a clean tune becomes over-filtered and laggy feeling

i actually had the opposite problem going from Gemfans to HQs once, felt twitchy as hell. prop choice really does mess with a tune more than people think. tbh i just retune from scratch every time i switch props because trying to chase the old tune is maddening. probably not what you want to hear but blackbox a few packs and look at the step response traces, thatll tell you faster than guessing