Chiptuning glossary
Plain-English definitions of the ECU tuning terms you'll see across the YAS Tuning file service, from Stage 1 and checksums to DPF, EGR and WinOLS.
- Stage 1
- A software-only ECU remap on an otherwise standard vehicle, optimising boost, fuelling and timing within factory hardware limits.
- Stage 2
- An ECU remap matched to supporting bolt-on hardware such as a downpipe or intake, giving larger gains than Stage 1.
- ECU
- Engine Control Unit, the computer that manages engine operation. Tuning rewrites its calibration (maps).
- Chiptuning
- Modifying the ECU software to change engine behaviour, most commonly to increase power and torque. Also called remapping.
- Checksum
- A validation value in the ECU file. A tuned file must have corrected checksums or the ECU may reject it.
- DPF
- Diesel Particulate Filter, an exhaust component that traps soot. Its management is controlled by ECU software.
- EGR
- Exhaust Gas Recirculation, a system that routes exhaust gas back into the intake to lower combustion temperature.
- AdBlue / SCR
- Selective Catalytic Reduction, an after-treatment system using AdBlue fluid to reduce NOx emissions on diesels.
- WinOLS
- Industry-standard software for reading, editing and managing ECU calibration files.
- Flash
- Writing a modified calibration back onto the ECU using a tool such as Alientech, Autotuner or CMD.