ECT IAT Adjustment 1 and 2 — additive or conditional? NC1 2.0 MZR
Posted: May 25th, 2026, 5:49 pm
Working on knock protection for a 2008 NC1 running the Stage I 93US base tune with header, AEM CAI, and custom exhaust. Tuning with the full editor.
I've made changes to both Timing - ECT IAT Adjustment 1 and Timing - ECT IAT Adjustment 2 at the IAT 104–122 rows, ECT 176–194 columns — adding retard to protect against heat-soak knock that appears at 90°F IAT / 187°F ECT.
Before flashing, I need to confirm: are these two tables applied additively (values summed), or do they apply under different conditions (e.g. open loop vs closed loop, or load-based switching)?
If additive, my combined correction is -2° at ECT 176 and -3° at ECT 194 for those IAT rows, which stacks on top of 1° already pulled from the base timing maps — likely overcorrected. If conditional, the correction is bounded to whichever table applies at the knock conditions.
Any documentation or source-level insight appreciated.
TMD
I've made changes to both Timing - ECT IAT Adjustment 1 and Timing - ECT IAT Adjustment 2 at the IAT 104–122 rows, ECT 176–194 columns — adding retard to protect against heat-soak knock that appears at 90°F IAT / 187°F ECT.
Before flashing, I need to confirm: are these two tables applied additively (values summed), or do they apply under different conditions (e.g. open loop vs closed loop, or load-based switching)?
If additive, my combined correction is -2° at ECT 176 and -3° at ECT 194 for those IAT rows, which stacks on top of 1° already pulled from the base timing maps — likely overcorrected. If conditional, the correction is bounded to whichever table applies at the knock conditions.
Any documentation or source-level insight appreciated.
TMD