Is it normal to have 4-5 psi fuel pressure drop on a returnless system
 

I am seeing 4-5psi drop at WOT in boost. I'm going from 64-60 psi with my MP112 on a 5.3 with returnless fuel system.

Perfectly normal

What is the maximum acceptable drop?

mine dropped from 68 psi to 64 psi under full boost. It is normal

Thanks for confirming that. It still bugs me though, and if I add more boost which I plan on pretty soon. Is there a way I can add or make the pressure more stable without switching to a return system? Or is this the main reason why people switch to a return system?

return FTW

im currently running a returnless with 255 intank and 72lb injectors and im running lean past 5k rpm with 10lbs of boost.

I should be converted over to return by the end of the month

I think you are concerned about an issue that does not exist. I have run up to 10 psi to 6600 RPM without any issues on a return less system....can it be better, sure.....

However I would not be too worried about it.

sure, but if you plan on upping the boost its only going to get worse.

how much boost do you plan to run up too?

well shit, for all i know im prolly still running the factory pump. i was TOLD there was a 255 intank when i purchased the truck.

10 psi.......I do have a pump in the tank, as I can only assume the OP does as well.