Speaking of Walbro in this case...
The 255LPH High Pressure version at 12 volts can only deliver 83.3LPH at 100PSI versus the 97.3LPH of this new 400 pump. So you're thinking ok slight improvement. However at 60PSI comparison the 255 delivers 193.1LPH and the 400 delivers 287.9LPH! That is a huge difference in flow! Seeing as this new pump is quieter, heats the fuel less, and is that much more efficient... even for low HP all motor builds would this not be the better choice for running high pressures to maximize the efficiency of the newer style Bosch injectors?

Now what about the Aeromotive 340LPH pump? It has incredible flow, uses turbine style like the Walbro 400LPH so it has those benefits, and it looks like it will do great with high pressure. I'm planning on running like 60PSI base pressure since the Bosch injectors get even better at higher pressure.

My main concern is too much flow. I have a -6AN line from pump cover to fuel rail and I was planning on using a -4AN line as a return but will that not be sufficient to return all of this fuel? Should I use a -6AN as a return?

Comments, questions, concerns, theories, opinions... GO!

 

Nobody knows?