sounds about right for equipmnet constant speed motors . what type of waste gate on the turbo does it have ? spring type is the most common and rarely has issues. I have a 2003 JCB skid steer with a perkins 92 hp 4 banger in it . The turbo waste gate is a spring type on it also. Basicly the spring provided resistance for the boost pressure to push against and once it hits the spec it starts to blow open and let the boost blead off so you dont replace your head gasket.