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Turbo K20Z1 Breaking Up for No Known Reason

Posted: Tue Jan 13, 2026 7:26 am
by Chrishdmn
I have a turbocharged K20z1 swapped EG civic running on a KproV4, with Alpha 2200cc injectors, with a PSR74mm turbo, sidewinder turbo manifold, running NGK BKR8EIX plugs gapped at 0.018”, running on E85. I am going through the tuning process, and the car keeps breaking up at 4700-5500 rpm no matter what. It has done it with VTC locked to 0 degrees, it has done it with my current calibration where VTC isn't locked, it has done it with vtec engagement moved to 6500 rpm, and it has done it with vtec engament at 4500 rpm. I have verified fuel pressure is in the correct range, I have tried a different set of coils that I know are good, I have verified I have all of the necessary grounds are there, and have cleaned all of the grounds/made sure good contact was being made. I am not too sure what else to check apart from valve lash. The misfire is harder to see in the data logs, but I have posted them, as well as my calibration. Any input would be greatly appreciated. TIA!