used a lot in the biking world to 'tune' fuel injected models, but why not apply them to cars? i think a lot of jap cars use similar things from apexi etc?

these modify the signals to the injectors or ignition in order to smooth out standard emmisions friendly maps, or to take account of filter and exhaust changes etc.

quite advanced little things eally. can even do individual cylinder injector trimming. no good for a boosted engine, but could be alright on a n/a conversion to throttle bodies for example

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