The K&N 50-3119D is a NextGen Diesel Dryflow cold air intake for the 6.6L Duramax L5P in 2020–2026 Chevrolet Silverado and GMC Sierra 2500HD and 3500HD trucks. The Dryflow lifetime engine air filter listing for the 2020 Silverado 3500 HD shows this intake as fitting, and the manufacturer's 2020 Sierra 2500 HD page also lists 50-3119D as fitting. The tube is a roto-molded design, which is the manufacturer's own term for how the tube is formed. Compared with the factory airbox, the case for buying it is intake-air flow and a cleaner, reusable filter setup, not a guaranteed power jump. One L5P owner on a user forum notes that during a diesel particulate filter regeneration the ECM modulates the intake air throttle, which can limit what any cold air intake does. Expect modest, driving-dependent gains, and ask the seller to confirm the exact fitment for your cab and trim before ordering.
Buyers searching for a 2020-2026 L5P cold air intake, a 2500HD 3500HD Duramax intake, or a K&N 50-3119D upgrade should also know what owners report about aftermarket intakes in general. One owner on a user forum says an aftermarket L5P intake gave a noticeable difference over stock. Others on user forums describe an aftermarket intake that barely fit and did not line up with the turbo intake tube, so dry-fit the tube and clamps against the turbo inlet before final tightening. Check that the intake clears the engine bay and that all sensor connections are reseated.
