Closed loop means that the system uses an 02 sensor in the exhaust pipe to measure the proportion of oxygen in the exhaust gas, and using that sensor dynamically changes the map to the injectors, in essence it 'learns' as it goes and keeps the fuel ratio adjusted as conditions change. Standard EFI maps 'approximate' the best map for a stock motor which is why there are problems when standard engine mods are made, the existing map cannot adjust itself, a closed loop system can adjust itself to a limited degree. Obviously if the mods are sufficient to go beyond the basic closed loop system's limits a new map must be uploaded, but with that said once the new limits are entered the system will continue to learn the motor and adjust itself on the fly. My 07 Harley has a closed loop system which I upgraded to use broad-band 02 sensors, the stock setup has narrow-band 02 sensors which cannot keep up with the motor beyond a set RPM range. Hence my question to the .org, does anyone have some experience using a closed loop system with an 02 sensor in a Gen 1, I'd like to set my Busa up like my Harley, the closed loop system eliminates the 'mapping' hassles without the need for a dyno.
Thanks.
-Jim
