First real bench run of the wide‑band knock detection pipeline on the M1 prototype. The goal was to validate the DSP filter against a known‑good reference engine before we trust it on a running car.
Setup
We drove a piezo knock sensor through the M1 analog front end and injected recorded knock events at the block. Sample rate was fixed at 50 kHz with a 6 kHz band‑pass centred on the first resonant mode.
Results
Detection latency landed under 2 crank degrees at 6000 rpm — comfortably inside the window we need to pull timing. False positives from valvetrain noise dropped to near zero once we gated on the combustion window.
What surprised us
The biggest noise source was not mechanical — it was ground bounce from the injector drivers. Star‑grounding the sensor return fixed it completely.
Next
Closed‑loop timing retard on a running engine, logged live. More soon.