Brandfetch Edge Impulse Logos & Brand Assets WinmaX W4 Performance Trackday Brake Pads. WinmaX W4 brake pads are a semi steel based compound suitable for track use in low to mid level competition environments. Used in racing conditions by small cars and heavier cars doing limited laps. W4 is ideal for the track enthusiast wanting bang for bucks! Note: Winmax W4 is not stocked in many shapes and mainly used in Hyundai Excel X3 Racing. Other than this application, W4 is generally special order only.