TUNING
Stage tune — Stage 2 / Stage 3
Definition
Stage 1 = software-only on stock hardware. Stage 2 = software + supporting hardware (intake, downpipe). Stage 3 = bigger turbo / fuel system / hardware build with a matched calibration.
Why workshops care
Standard tuning industry vocabulary. Diesel turbos typically gain +20-30% (S1), +35-50% (S2), +50-80% (S3). Petrol turbo gains are smaller per stage.