RomRaider

ive got a 2005 uk wrx with a walbro fuel pump, sti injectors and a fuel pressure regulator.
now my question is because the fuel pressure has been upted to around 3.5bar does that then mean my injectors need to be rescaled if so then how much?

they are currently set to 550cc

Yes they will need to be scaled up.... do you have a wideband?

If you have a Wideband, you could raise the scalar up to say... 620cc, most likely you will still be running richer (play it safe)... then bump it up a little more.. etc. until your WOT wideband readings are about the same....

There is probably some math that would get you very close without, but I prefer to do things this way and in the end you can get it nailed down. If your MAF is scaled properly... you might want to utilize the Injector Scalar tool in the logger as well...

I'm not sure if latencies will need to be changed for increased pressure- all the injector work / changes I've made have not included raising fuel pressure so someone else can chime in there...

thanks for your reply mate, my local tuner (aldons) recon they should be scaled to 660cc but to be 100% sure they would need to know what the fuel pressure was before the fuel regulator was fitted and what it is now the fuel regulater is fitted.
i do have a wideband and i think my fuel is running a little rich, which i think might be causeing some knock that im getting under load.
if i use the injector scaling tool do i need to change the rpm range, afr range and maf range to suite what im currently running for example the loggers afr range is currently set to 14.0 - 16.0 surely this would need to be changed?
thanks