| Improving engine power through mechanical upgrades | | | | and ignition mapping changes progressively in reaction |
| such as free-flowing exhausts, intakes, turbochargers | | | | to this. After modifications, very quickly the ECU can |
| and intercoolers will boost the amount of airflow into | | | | reach the end of its scaling so that in essence fuel |
| the engine over stock. Any increase in airflow is | | | | and timing becomes fixed at the last set values. This |
| immediately picked up by the air mass sensor. This | | | | leads to driveability and reliability issues. |
| causes the following things to occur: | | | | The OE boost control is calibrated to suit a known |
| Increased load forces the ECU to operate in areas of | | | | set of exhaust and intake dynamics. More efficient |
| the fuel and ignition maps that it was not calibrated | | | | parts can throw the boost control system to far out |
| for, resulting in fuel mixtures that are too rich, eating | | | | of sync for its closed loop boost control system to |
| up some of the power gains made by fitting the | | | | compensate for. Wild boost fluctuations, over |
| parts in the first place. | | | | boosting or even under boosting are all possible |
| Reductions in exhaust back pressure enables more | | | | consequences. |
| ignition advance to be safely run in the mid range | | | | Products that modify the way in which the engine |
| than the active ignition control system is programmed | | | | management system works, in order to address the |
| to allow, thus compromising peak potential power. | | | | above issues are broken up into four broad |
| Outside of the range of active timing control the ECU | | | | groupings. They include re-flashing the OE ECU; fitting |
| is effectively deaf and is programmed with a safe | | | | an interceptor type add-on controller; complete |
| set of ignition timing values. These safe ignition values | | | | replacement ECU replacements; and finally plug-in chip |
| are for an unmodified engine. At high RPM and loads | | | | upgrades. All of these upgrades have their place in |
| ignition timing needs to be retarded, especially after | | | | the grand scheme of tuning things, each with their |
| 6,000 RPM, or the engine can start to detonate. | | | | own pros and cons. |
| Normally as engine load and RPM increases, both fuel | | | | |