Originally Posted by Crazykev
Tim, do you think I will need larger injectors than my Sti pinks for the PE1818? I'd rather not if I don't have to. Or should I invest in an adjustable FPR?
I want to be sure everything goes perfect this time
Anyone have a compressor map for an 1818?
You can get pretty close the limits with STi pinks and a VF39, 30, 34, of VF22. No harm done to get something a little bigger. I'll look for information and get back to you.
In terms of fuel pressure as a solution:
You could raise the base pressure for the pinks and thus increase their overal flow. however, a rising rate FPR is most definitely not a good idea. The fuel calculations inside the stock ECU are based upon static fuel pressue. The only reason fuel pressure increased with boost is to offset opposite positive manifold pressure.
Base subaru fuel pressure = 43 PSI
20 psi of boost fuel pressure at the rails is = 63 psi
63 psi fuel pressure - 20 psi boost pressure = 43 psi static
In other words, the injectors flow at the same rate at a give duty cycle irrespective of boost pressure.