Looking at an S3 in particular with stock pumps IE No HPFP and stock FPV

Just trying to get a better understanding of the fuelling on these cars

LPFP feeds HPFP, and then we have the FPV to vent pressure above the max of the valve.

Requested fuel pressure maps and the sensor regulate the rail pressure and then the injectors opening times control AFR as requested by the ECU.

So for any 1 AFR request we could have 2 injector MS. Ie low Rail pressure and high injector MS or high rail pressure and lower injector Ms giving the same fuel flow. in much the same way the 1,8t could have a 3 or 4 bar FPR with the same injectors and get differing flows .

So my question is how much can you push the stock HPFP/rail pressure maps and what is an acceptable Ms for the s3 injectors before you need to upgrade to a Larger HPFP?

Obviously the answer is to run the car up with increasing load/boost and then increase in the rail pressure to try and maintain the required AFR and MS to the point where requested and actual start seperating or InjMS gets to high/maxed but does anyone have info on where you can start to expect this?

Thanks Gman, Gives me something to work with..

Finally the figures here are BAR?

Yep. Set the factor to 0.005 if you want to express in bar.

I've already set the conversion to 0.005 so just confirming that is bar. Thank you..