'03' SS Silverado's seem to be mechanical driven as far as boosting the fuel to drive the 42LB Injectors that come standard with the Radix Systems and what we procharger guys end up installing after the fact. The '03's need to have some form of fuel pump assister (In essence, a 2nd fuel pump or upgraded fuel pump) either in line or in tank.

The '04's seem to be more about the Manifold Pressure being sensed by the PCM and adjusting the system to compinsate to maintain the constant pressure needed.

Has anyone had any experience in this, or am I going to Guinea Pig This?

 

We installed a P1SC on my fathers 03SS. It came with an mechanical fmu that under boost restricted the fuel return line that increased fuel pressure to about 110 psi. This was used in conjunction with the factory injectors & the auxillery frame mounted fuel pump(came with the p1sc kit).

We ended up deleting the fmu, & installing 44lb marine injectors, the flow rate was dialed in using the map tables in edit & then fine tuning the fueling by using the ve tables(speedenisty tune). After that we then yuned the power enrichment vs. rpm to get proper afr.

In 04 gm made the fuel system returnless so the fmu cannot be used, the factory injectors would have to be replaced

 

Injevtros and a tune, that is what I am doing.

 

42 lb injectors and a walbro inline pump with a tune. it will run a million times better than a FMU anyway. the FMU is kind of a cheap band aid and i dont trust it at all.

 

You will have to modify your fuel lines since the returnless fuel system doesnt have the filter on the frame anymore. I talked to a guy with a Silverado SS with 9lbs and his stock pump did fine.