It varies across different Honda engines and also depends on the model it's in. For example: K20A engages at 6,200rpm - JDM DC5R/EP3R K20A2 engages at 6,000rpm - AUDM DC5R K20Z1 engages at 5,800rpm - AUDM DC5S B16B Type R engages at 6,200rpm - JDM EK9R B18C Type R engages at 5,700rpm - JDM DC2R