First reason is the returnless fuel system, second reason your rb motor has six injectors feeding smaller cylinders compared to our four. The supercharger also makes a lot more power on the motor than what is seen at the wheels.

 

^^ isnt that the usual case?

 

Its still 2.5L though so its using more fuel? Is the returnless fuel system that big of a deal when it comes to fueling these things?

 

Well if both engines are at the same power level and flowing approximately the same amount of air, then the inline 6 has two more cylinders over the 2a to spread the load. Each cylider would require less air and fuel per cycle on a 6 instead of a 4. Also, each rb25 cylinder is much smaller volume than a 2az, because 2.5l although slightly larger than our 2.4 is the total displacement of all six cylinders.

Having a returnless style fuel system is also a huge disadvantage especially with boost. Our systems are designed to have the vaccum of the engine help draw the fuel from the injectors into the firing chamber, which has its limitations when the volum e the injectors are firing into has positive pressure thus forcing the fuel back in. A return style system would let the whole system be under constant pressure allowing it to flow much more effeciently.

 

so what did you use to check your air temps?