I recently Put d16z6 engine and tranny into my car and the ECU of course . I think the vtec is suppsed to kick in at 4500rpm?? but mine kicks in at a little over 5500rpm. Right before it kicks in it I hear a wierd like wistle sound or screach. I also dont know should I hear a big difference with vtec engagement with engine like you do with DOHC engines??? I can feel it but not hear it so. I have exhaust, intake and header. Do Vtec seliniods go bad. Also my new engine does not smoke or make any other wierd noises but the car has a lot more engine vibration inside than before. like in the floorboard. All the engine mounts are fine but I dont know wha the problem is?? If you have any insight I would appriciate the input Thank you.