The manufacturers produce them in a so called big quantity production.

For this reason there are developed engine software products, that  consider all possible tolerances (the sum of all deviations of all parts) and eventualities. The manufacturer cannot carry out,   due to cost reasons,  any individual tuning in a car. In this case,  almost all ISO certified manufacturers inspect  just each Xth car. The sum of all tolerances in the manufacturing process can be so high that the softwares may be programmed with excessive security reserves.

Same engines differ in the performance from one car to the other  until 10%. In addition to this,  engine and engine softwares  are tuned to the global use.

With this, the following influence sizes are programmed  in the software development as a safety reserve.

• Different  fuel cleanness
• Different  octane content in the fuel

• Different air moisture content (Taiwan 98%)
• Different altitude and much more

At the manufacturer it is normal that new engines are finished with a lower performance than with that performance they actually were designed for. Here can the manufacturer, through a simple software update, present to the market a so called revised version engine generation, without having high development costs (the tests happen at the consumer) The manufacturers always have something new and appear to the consumer as being very innovative.