1. Introduction The K20Z3 is a high-performance 2.0L i-VTEC engine produced by Honda from 2006 to 2011. It is notable for being the last VTEC engagement on the intake cam only (with exhaust cam phasing via VTC) and featuring a factory 6-speed manual transmission. The engine is managed by a specific ECU (Engine Control Unit) , most commonly the 37820-RRB series (e.g., RRB-A13, RRB-A11) for North American Civic Si models.