Factor in knock and engine roughness sensors, and variable boost control present in some newer cars, and the house of cards that is a balanced engine management system grows in size and complexity. But today's increasingly inclusive OBD 2 engine management systems offer a huge benefit in their complexity, especially when coupled with flash-based programming-the ability for tuners to manipulate every parameter of their functioning instantly, and in real-time, to custom-tailor ECUs to govern virtually any engine modification at hand. Information contained in older ECUs was mostly ROM-based, or read only memory; microchips were constructed containing pertinent data and could not be modified. If ECU data needed to be changed, the existing chip(s) containing the data had to be physically extracted and replaced with a custom-fabricated or "burned" chip containing new information-the tedious and semi-permanent process of ROM tuning. "But today's ECUs are mostly flash-based," explains Tadashi, "and tuning them shouldn't be confused with ROM tuning." Changing information contained in flash-based ECUs can be controlled entirely with software, usually through a vehicle's OBD 2 diagnostic port. ...A process called reflashing.
With just a few key strokes on the laptop linked to his customer's G35, Tadashi-san is able to recalibrate MAFS voltage to compensate for the change in incoming air mass, correcting AFRs; adjust valve variability via cam timing throughout the rev range, maximizing overlap at specific stages of engine speed; and adjust ignition timing, throttle position, AFR and fuel cut-off along side it all-to fine tune the whole mix, maximizing the potential of the car's bolt-on power enhancers. In about as much time-and with about as much effort-as it takes to upload songs onto an iPod, Tadashi has tuned the G35's stock ECU to produce better than an additional 10 hp and 15 lb-ft of torque across the entire powerband, with plenty more room to grow, should the owner ask him to get "gutsy". And with a little more work, the ECU could be reflashed to govern forced induction or nitrous injection systems, a full naturally aspirated build, or whatever other crazy power scheme his customer might come up with down the road. ...Or reflash the ECU back to stock, should the car need to be brought in to a dealership for warranty work. "Only once the OEM sensors have passed their capacities," explains Tadashi, citing the MAFS as one such instance, "should the owner consider another option to reflashing." But at that time, we suspect the all-out race machine you feared your daily driver would ultimately become would be ready for that stand-alone EMS.