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Home GlossaryDatalogging

Fuel & Electronics

Datalogging

The recording of ECU sensor channels (RPM, MAP, AFR, knock count, IAT, ignition timing, fuel pulse width, etc.) over time, used by tuners to verify engine health and refine maps. Quality datalogs are the difference between safe and ruinous JDM tuning. Most standalone ECUs and aftermarket tunes provide data via OBD2 or dedicated logging software.

Related Terms

Knock Sensor

A piezoelectric vibration sensor mounted on the engine block that detects the high-frequency pressure waves caused by detonation. The ECU uses knock sensor signal to retard ignition timing in real time when knock is detected. Modern standalone ECUs (Haltech, MoTeC, Link, Syvecs) include knock control loops that protect tuned engines from bad fuel batches.

Standalone ECU

An aftermarket engine management system that fully replaces the factory ECU, offering complete control over all engine parameters. Popular options for JDM builds include Haltech, Link, AEM, and Motec for high-power or heavily modified applications.

Wideband O2 Sensor

An air-fuel ratio sensor (commonly Bosch LSU 4.9 or NTK UEGO) that reads accurately from 10:1 to 20:1 AFR. Replaces the narrowband sensor used by stock ECUs which only signals "rich vs. lean." Required for any tuned forced-induction build. Mounted in the exhaust collector or downpipe.

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