For the most part, there is no need for specific settings. If you're referring to the right FFB Mult value to use (to avoid clipping, for example) you may find people mention a specific car in places, but I don't think there's a repository. For most official content, the recent stuff especially but including things like the historic F1-F3 cars, a mult around 0.75 will mostly eliminate clipping so that would be a good starting point. If you want to determine the right level yourself, you can use something like a SimHub display, which I believe is a paid option, or you could use a telemetry output plugin and read the values manually (or via data input into a spreadsheet), or you could use a telemetry plugin and associated software to display and analyse it. My DAMPlugin can do this with Motec i2Pro, for example. Most of the other settings, like Minimum Torque (?) and smoothing, are things you set for your wheel rather than each car. So making sure you have your wheel settings correct is also important, or FFB Mult can't recover it. Generally if you're going to minimise clipping your wheel should be at full strength.
Yes the problem is I'm working on modifing an existing mod but that mod ffb is too week (my ffb from other cars works great) you can barely feel it I would like to increse it but don't know how
There are various things that will affect it, I am not expert, but some are those: Larger caster value, Lower nominal ffb value, Larger steering lock to lock angle, Lower steering wheel lock to lock angle, Suspension geometry, I also think that rideheight has effect, Tire grip- base and sliding, Track surface grip, Load on the front wheels, Scrub radius, .... All those things are some bits of whole physics pie, and it is beautiful. Though nominal ffb value is not very physical, but it is obviously necessary.
@Goncalo Costa Sorry, I didn't realise this was a modding question. What mantasisg has said is what I should have said