When it happens it's really loud, it's annoying I hear it even with my Z1 straight pipes. Today it was hot out and it took a lot of effort to make it tick, pushed the car a couple of times before it happened. The other two times I tested it, it happened the first time I boosted. Also I feel like my plenum gets too hot. The engine I had previously did get hot but not this hot in my opinion, but that's just judgement never took any temp readings.