Pressure always drops off. What did the pressure read and what was the flow rate?
Two Possible solutions:
1. A Kenne Bell Boost a pump will add additional fuel at a preset amount of boost, 3 or 5 lbs. This set up works but needs to be adjusted for by the tuner. Code3 has used this set-up with good results.
2. 20% larger injectors. Dino, a tuner in California, has done this set up on SLK 32 AMG's and it has worked. He says that the factory pump is enough.
I know it gets confusing because everyone always talks about pressure but to much pressure from the pump isn't good either. One - it opens the FPRV, two- it can cause the pintel in the injector to slow. When the pressure drops off, the pump increases flow. The amount of flow will then determine if you have enough fuel to tune with. The KB set up works because when you approach high rpm's, the injectors take away alot of the pressure in the rail, the BAP supplies 12-20volts to the pump at this time to spin it faster, and flow is greatly increased. If you were to try and snap shot the pressure it would proboably be higher then 60 pounds. It is running basically unrestricted because of the rpm's and rapid injector firing. With the above link the car was untunable not due to the injectors but to the fact that both pulley's go out side the MAP calibrations because of the boost levels which creates a a different set of problems. The car is now running fine with the 185 pulley and bigger injectors.