I recently changed out my fuel system got rid of the procharger regulator and added a Aeromotive 1 to 1 along with a high flow fuel pump and bigger fuel lines . I have a Mefi tunning program and was wondering should I be tunning using the 1:1 regulator which is increasing fuel pressure 1 psi to 1psi of boost. Or do I just leave the fuel pressure constant and tune for extra fuel through the MEFI ?? . It is a 454 Mag efi running 5-6 psi of boost. I also use a 2 bar Map sensor to capture the boost . As of today it is tunned for proper air fuel using the 1to regulator ?

THX

Use the regulator to increase the fuel pressure to the injector to offset the boost pressure in the manifold that's pushing on the injector.

that's sounds great but how do you get to a safe afr like 11.8 or 12 to one when boosted at max rpm since the mefi is operating outside its ability to read

No clue on the MEFI, I run the Fast system, I like to tune in real time. I was just answering the regulator question.

Fuel pressure through a boost-referenced regulator that is not 1:1. Very tough to tune one and they are inconsistent day to day with varying weather conditions. Just right one day, fat the next....BOOM the day after that!