lets talk about fuel pressure regulators. if a FRP is vacuum refrenced as in vacuum on the regulator causes the pressure to drop. then wouldn't it cause pressure to increase with boost? i mean if vacuum pulls a diaphram up wouldn't boost push down?

 

I would think so...I'm running the stock one and my FP increases the higher I get into boost....

 

The FPR on my Radix is taken from the manifold after the lobes as is the map sensor. They both see vacuum/boost reference. I would guess that this FPR acts as a switch in that any vacuum will apply normal fuel press. regulation(preset) and boost will increase (switch) fuel press. to a fixed higher press. regulation. Not quite sure myself so maybe somebody else will chime in and explain this better.

 

A 1:1 FPR will increase FP in direct proprtion to boost to compensate for the decreasing IFR against boost. So if your base pressure is set at 60psi, at 8psi of boost your FP will be 68psi. This keeps your IFR constant. Conversely, your FP will drop when you go into vacuum.

 

so thats how the stocker on the return style system work also. correct? and how much does it lower fuel pressure as per vacuum? is that 1" to 1psi ratio?

 

Pretty much, only there is 2" of vacuum in 1 psi of air pressure.