Beav pls, no-one likes pCARS here :lol:
When I first switched to a Logitech G25 I was coming from using a keyboard and the games of the day were TDU1, NFS Carbon, and simulations such as GTR 2 and Race 07. That said I did
lazily try pC1 with keyboard.
You should be slower when starting out, just as if you were learning a new track for the first time. Slow, smooth and clean, focus on technique (slow in, fast out, racing lines, look for the corner exit instead of right in front of you, etc). You may also want to review/disable some of the assists that were relied upon for gamepad inputs. There will always be some aliens who can achieve great times without a wheel, but you should find a wheel to be more fun and allow for greater consistency. I would only caution not to fall into the trap of thinking that stronger force feedback is better. It'll just tire you out quicker and possibly make your inputs sloppier. Real cars are designed and setup to be as easy as possible to drive.
Set some before and after time trials and race against a former gamepad ghost lap that you record.
Here's one of the latest races I did on PS4 at the same track with a wheel. You'll obviously see how it is less twitchy. There's also a decent comeback effort and some battles worth watching if you've got the time to kill ;)