The 370z just like the 350z are designed with a part called a knock sensor. The whole purpose of this part is to detect knock if it occurs and then will compensate by adding more fuel to the chamber to prevent further knock from happening. Knock can occur due to the fuel not having enough octane. Running 87 octane will decrease your hp but that is all it will do.
Nissan 370Z Knock Sensor - Nissan OEM Engine Mechanical
What does a knock sensor do? - Yahoo Answers