Unfortunately there is no way to lock default setups in ACC. The Safe & Aggressive default setups are fairly good and do not need much of a tweak. Here we can post setups and guides to help with tuning.
it looks as if the default setups are different for every track, so if there's one you particularly like, stick with it. i'm liking how noticeable the tweaks feel in the handling
@JJ_Penguin might be good to add in the first post here the generic wheel setting for each car, or a link to where they are found ?
https://simsource.azurewebsites.net/tools/fuel-calc Handy link to help calculate fuel requirements for races.
it's uncertain if pc setups will transfer to ps4 atm, they definitely have not in the past, maybe the more updates we get the closer we get
this from the pc roozers on ACC (cheers boys), tuning these cars takes a lot of time/energy/trial & error to find the time on the board as well as matching what you want the car to do... this should help to simplify the process at the least https://www.dropbox.com/s/vtm9iwvccbnsq2r/Roadracing.pdf?dl=0
You can make this game as complicated as you like. That forum is for those that would spend days on a setup.