The Wilwood 150-40-6617K is a four-pad set of BP-40 high-temperature racing pads cut to the #6617 pad plate, which the manufacturer's Aero4 and Aero6 caliper pages both reference. The BP-40 is a high friction pad with an aggressive first-touch response, decent low-temperature response, low wear during sustained high-heat braking, and strong resistance to heat fade. That profile is what separates it from a stock or street pad on a dedicated track car that sees repeated hard stops, where pedal response has to hold as rotor temperatures climb. Match the compound to your heat cycle: asphalt and road race use usually calls for compounds rated above 1000°F, while dirt track, drag race, and street performance applications usually operate between 500° and 1000°F.
Owners on user forums describe the BP-40 as finicky to bed in and to bring up to operating temperature, and one who moved to a different compound said the BP-40 was not nearly as linear and super temperamental to bedding and bringing the pads up to temp properly. Cold running is also a known rotor-wear risk, since pad tearing up rotors is typically a sign that the pad is too cold. Because the pads ship non-bedded, plan for a proper bedding cycle before your first track day. Confirm the #6617 plate and caliper pairing before you order, and verify that your rotor material is on the manufacturer's list.
No. The manufacturer classifies the BP-40 compound as racing only and not intended for street use, with listed applications including road course, oval pavement, dirt, and off-road.
The manufacturer's caliper pages list plate #6617 for the Aero4 and Aero6 radial mount calipers. Confirm the full compatibility list with the manufacturer before ordering if your caliper is not one of these.
Owners on user forums who switched from BP-40 to BP-30 report that the BP-30 is more linear and tolerates heat well, which is why some prefer it as a track pad. Results vary by car, rotor, and track, so match the compound to your own heat cycle.
This is a straightforward pad swap in an existing Wilwood caliper, but the work is in the preparation. Start by confirming the pad plate matches your caliper, then replace the pads and inspect the rotors for wear or glazing before you bed the new set. Because the pads are non-bedded, follow the manufacturer's bedding procedure before track use. Owners on user forums describe the bedding process as a real chore, so budget time for it and avoid hard stops while the pads are still cold. Keep the pads up to temperature during the first sessions, since cold or improperly seasoned pads can leave pad-transfer marks on the rotor face. Use the manufacturer's install sheet for torque specs and tool requirements.
