Q: What is a plenum spacer?
A: The stock plenum slopes down towards the front of the engine. Nissan designed this in order to clear the stock strut bar and hood on the 350Z (function after form). This sloping design restricts the airflow to the front cylinders, but an aftermarket plenum can help the front cylinders breathe. Aftermarket plenum spacers either increase the overall height or remove the downward slope in the design, allowing more volume and greater airflow to all cylinders. Higher airflow is needed to achieve more power.
Q: What is the best modification to increase BHP in a stock 350z?
A: Because of the effectivness of the adaptive ECU in the 350z most power upgrades are ignored. The only way to fully maximise performace additions is to either fit a piggy back ECU or have the stock one remapped in order to alter the fueling thus increasing BHP.
Q: What is FI and NA?
A:
FI - Forced Induction: This is when air is forced into the engine by means of a Turbo or Supercharger.
In short:
More air means more fuel is injected
More fuel and air = bigger explosions
Bigger explosions = Serious Power
NA - Naturally Aspirated: This is the method in which the stock 350z allows air into the engine. Air is drawn in via the filter, throttle body and pleum naturally as the fuel ignites.
Some for the moment....feel free to amend any of it if you want to use it.
R