When a sports exhaust is fitted to a car apparently a re-tune of the ECU is required. For a simple example consider a regular unmodified normally aspirated petrol car which then has a sports exhaust fitted to allow higher rate of air flow. I've read that an ECU tune is required to get the best performance. In this case which maps does the tuner change ?

  • As a side note, even if you don't get the ECU tuned, performance will change slightly as the ECU can alter timing map and other related variables within a narrow range.
    – NetServOps
    Jun 23, 2021 at 6:41

1 Answer 1


Timing, fuel delivery ie what is called the characteristic map.

If you want to get to grips with this, read up on the early engine controls such as the J and K systems by Bosch - these were simpler than the newest generation used now and may be easier to understand.

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