Ok, can somone explain to me how a returnless fuel system works? From what I have read this is what the Zs' fuel delivery system is. Also how the procharger FMU works with this.

 

I think it has to do with whether excess fuel pressure is returned to the gas tank or not. In a return system, excess pressure is simply bled off by allowing some of the fuel to spray back to the tank.

In a returnless system, the generation of fuel pressure has to be intelligently controlled, or else the fuel rail might rupture at a connector or the injectors might be damaged. A return system can have a less intelligent management of fuel pressure.

However, I don't know what the advantages of a returnless system are. Maybe more efficient?

Again, the above is based off of some stuff I read a long time ago so I probably got some details wrong.

As for the FMU, I guess procharger needs some "smarts" to make sure they don't build too much or too little fuel pressure.

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Jeff