and electronics that plug directly onto the spark plugs without the use of spark plug wires that are typically used in most engines. SAAB Models Utilizing Trionic Engine Management System: 2nd Generation 900 ("NG900") 1994-1998 T5 9000 1994-1998 T5 1st Generation 9-3 1998 T5 (Except Viggen, which is T7) 1st Generation 9-3 2000 to 2002 T7 1st Generation 9-5 1998-2010 4Cyl T7 2nd Generation 9-3 2003 to 2011 4cyl T8 Projects/Aftermarket (Non OEM) tuning There are communities working on reverse engineering electronic engine management systems ( EEMS) and particularly the Trionic EEMS. The work involves understanding the binary files stored in the ECU itself, and the changes that affect the car's hardware and operation of the vehicle. The T5, T7 and T8 management systems have been successfully manipulated to allow self-tuning for enthusiasts. There are also some alternative options such as interceptors like #Unichip that clamp the various inputs to the standard management systems, but they are restricted by the fact that fuel delivery generally cannot be easily increased as manipulation of the air-flow meter input and/or aggressive modifying of the ignition timing causes the Check Engine Light (CEL) to illuminate easily. This is due to a deviation between the expected and targeted torque and quality of emissions. It is, therefore, common to increase the fuel pressure across the board by using an aftermarket fuel pressure regulator when tuning is performed by these interceptor computers, trimming the fuel out instead. However, increased fuel pressure affects the engine's ability to idle due to injector lockup, therefore, an alternative solution of additional injectors instead of a raised-fuel-pressure regulator is proposed. The number of cars with such complex requirements such as Nira or MoTeC is very low so a full aftermarket engine management system is generally used in these cases. Glossary Sources include: Engine management system SAAB Trionic T5.5 APC, Automatic Performance Control CDM, Combustion Detection Module ECU, Engine control unit EGT, Exhaust gas temperature ETC, Electronic throttle control MAP, Manifold Absolute Pressure MIU, Main Instrument Unit ORVR, On board Refuelling Vapour Recovery system PWM, Pulse-width modulation SID, Saab Information Display TCS, Traction control system TPS, Throttle position sensor TWICE, Theft Warning Integrated Central Electronics VSS, Vehicle Speed Sensor WOT, Wide Open Throttle References External links , formerly a Community dedicated to giving Trionic power to the people! This site is no longer online. Founded by Andrew J. Weaver and Steven A. Hayes