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