@fastian04
First of all the claim that X was making 12-13 psi peak boost is completely wrong. You may have found a few posts here and there but there is massive amount of data available that shows X Turbos making 16-16.5psi peak boost all over the world (including PKDM). Ktuner and Hondata's extensive research proves the same.
What Honda did with the updated factory map in 2017 were two things:
- Reduce peak boost to 14-14.5 psi
- Open loop AFR (This forces the ECU to keep pumping fuel at a predetermined rate as opposed to closed loop system where the ECU determines AFR based on oxygen sensor values mounted on the exhaust side). Honda used open loop AFR to keep the AFR very rich (8-9:1) at WOT.
In short the combination of lower peak boost and rich AFR mitigated knock. Rich AFR essentially has a cooling effect on the cylinders as opposed to lean AFR which creates more heat hence increasing chance of pre detonation.
Someone also mentioned PKDM Civic not having knock sensors. That's not true at all because without knock sensors the engine would blow itself to smithereens. PKDM Civic does not record independent knock events (that function is disabled in the ECU). That is the difference between USDM and PKDM Civic when it comes to knock sensor/data logging.
