The Hawk HB141N.650 is the HP+ compound in Hawk's rear pad set for Audi and Porsche applications and the StopTech ST-40 four-piston caliper. HP+ uses Hawk's Ferro-Carbon friction material, which is built for autocross, solo events and light track days but still works on the street. Compared with a stock pad, the reason to pick HP+ is stronger friction and better resistance to fade when rear brakes get hot during repeated hard stops. That bite comes with trade-offs: expect more rotor wear, noise and dust than a street-focused compound.
Fitment centers on 1990s Porsche 911, 928, 944 and 968 rear axles, with a Ferrari 456 GT also listed. Audi applications appear under this part family, but the lists differ from source to source, so verify your year, model and caliper before ordering. Because the pad is sized for the ST-40 caliper at 0.650 in thickness, it can be a straight swap for owners running that big-brake setup. Enthusiasts searching for HB141N.650, HP+ Ferro-Carbon rear pads, StopTech ST-40 track pads or 911 rear track brake pads will find this is the right compound family to compare.
Sources differ. Some describe HP+ as a dual-purpose street and track pad, while others describe it as a moderate-friction track pad with more rotor wear and noise that is not recommended for regular street use. Confirm the intended use with the manufacturer before ordering.
HPS is Hawk's street-oriented compound, with lower dust and noise. HP+ offers higher friction and better fade resistance for hotter, more demanding driving, at the cost of greater rotor wear and dust.
