FlatOut 4: Total Insanity
46 Achievements
25-31h
PS4
Class Winner
Win a race in Derby, Classic, All-Stars classes
4.9%
How to unlock the Class Winner achievement in FlatOut 4: Total Insanity - Definitive Guide
This is pretty self-explanatory, but just a note to say I couldn't get this to pop in Quick Race Mode. It only seemed to work for me in career.
Simply win a race in all classes (Derby, Classic and AllStar). You will get this as you progress through Career Mode getting all Gold.