A client came with a car remapped elsewhere. Not running problems — just feeling “not quite right” under hard acceleration.
What was changed: Rail pressure +180 bar. Quantity +6% flat. One torque limiter +45 Nm. Two DTC masks. That’s it.
What wasn’t touched: SOI (completely stock). Smoke limiter (not touched — car running 1.18 lambda at full load vs stock 1.4). Pre-injection (stock). Cold start corrections (stock). Temperature compensation (unchanged).
What “not quite right” meant: Under transient load, the SOI mismatch was creating combustion timing inefficiency. Good steady-state pull but rough transient response.
This is not unusual. The buyer had no way to evaluate it. He drove the car, it pulled harder, he paid.
Learning to read someone else’s calibration is a skill. We work through this in Diesel Practice.