My car sits at 13.8 volts when running, and the fuel pump see's about 13.6..... what the heck are you talking about?
If the voltage drop is so bad as your describing, then tuning in the injectors would be a night mare because we would not have the fuel pressure in the fuel rail to run the injectors according to spec. Your describing a situation where if someone switches injectors, they would literally have to run for MANY hours on the dyno to tune it all back in because the specs for the injectors will be totally out of wack and totally useless to use.
I run a 255lph hv pump, and when I dial in my AFPR for 43.5 psi on the rail, thats is what I get. If I use the stock NON adjustable FPR I see 39 psi on the fuel rail with no vac. How much do you wanna bet that I would see the same even if I ran 60 lb injectors. Oh and guess what, even if I was making 15 lbs of boost, the 255 pump I have will easily make 55 psi to support that... and I see 59 psi when I'm running the AFPR at 43.5 at full boost.
Lets keep things simple, and NONE of us are at the point that a hv 255lph pump can't keep up.... except maybe Jim Demmitt
Frit
According to Walbro data, with 13.5 volts present, the 255 LPH "HP" pump will flow about 70 gallons per hour at 40 psi, and about 63 gallons per hour at 55 psi (interpolated data between 50 and 60 psi). So, 15 psi of boost means you need about 55 psi of fuel pressure. 63 gallons of fuel weighs about 378 pounds. So, on a car running 15 psi of boost, the 255 HP can move about 378 pounds of fuel per hour. Now, we all know that injectors are rated in pounds per hour. I believe that those rating reflect 100% duty cycle. Six 60 pound injectors at 100% duty cycle can move 360 pounds of fuel per hour. So, as you said, with 13.5 volts present, and 15 psi of boost present, the Walbro 255 HP can easily support 60lb injectors. Especially because you would really only want to run the injectors at 80% duty cycle maximum, which would be 288 pounds per hour.
However, Walbro's data indicates that with only 12V present, the 255 HP pump will only flow 53 gallons per hour. That's only 318 pounds of fuel. So that is actually not enough fuel for 60lb injectors running over 88% duty cycle. If the injectors stay at 88% or less (as they should), you will be fine.
Now, you are saying that your car is getting about 13.6 volts present at the fuel pump. However, don't forget that voltage drop increases as current flow increases. You didn't specify under what conditions you tested the voltage at your fuel pump. Was it idling? Or was it under full boost? The pump draws 7.5 amps at 40 psi, but it draws about 8.7 at 55 psi. Of course, if you were only getting 0.2V of drop, then it won't make much of a difference. I wonder if others have gotten similar results to what you got. If so, that's really good news. I hope you're right!
I find it interesting that, if we can all get 13.5 volts or more at our fuel pumps while running, then even the 190lph low-pressure pump can pump 44 gallons (264 pounds) per hour at 55 psi. That is enough to support 42lb injectors at 100% duty cycle. It's actually enough to support 50lb injectors at 88% duty cycle.
And by the way, the High Pressure version of the 255lph pump doesn't even start to pull away from the regular version until about 65 psi. Which none of us is likely to exceed "... except maybe Jim Demmitt."
Information gathered from charts at:
http://www.autoperformanceengineering.com/
By the way, what are you trying to say about the tuning problems? It wasn't clear to me. The fuel demands at idle and low-rpm operation are pretty small compared to the fuel demand at high boost and high RPM. So a pump like this running at a lower voltage, even turning at half-speed, should have no problem maintaining adequate fuel pressure during those situations. When the load rises (indicated by a signal such as MAF voltage or manifold pressure), the Boost-A-Pump increases the voltage to increase pump output. That allows it to cope with the demands of the injectors at those times. As long as you choose the proper setpoint for your load trigger, fuel pressure will never drop below the desired level.