Ok this is a fmu question, let the bashing begin about FMUs =[

but anyways
I'm currently working on a fmu 12:1 ratio setup and for my pump side, I'm opting between a in-line pump or a intank pump (I have a friend that is selling his walbro 255lph in tank pump for $30). I have looked over the walbro 255lph flow rate graph and I feel like with that I will be only be able to push 7 psi, is that correct? I'm wanting to push 8psi so I am currently deciphering whether to get that or a high volume in-line.


Here is the graph for the walbro gss342 @ 7psi the fuel pressure would be at 122

http://www.expressfuelpumps.com/images/GSS342chart.jpg

The difference between 7 and 8psi won't make any odds. Your car will be **** on the FMU.

I know fmu setups are not that great but that was not my question. I was wondering if the in-tank pump would be fine for 8psi or would I have to go for a in-line one.

i dont reccommend the FMU either but to help with your question...generally you must use an inline pump with the FMU setup. You might be able to get away with a Walbro 255HP in-tank pump, as you can see from the chart below its the only in-tank that can flow anything at all at those types of fuel pressures

well according to ur graph I can push 8 psi then but why is urs different?

you realize that flow and pressure are two different things? you could probably get away with 6-8lbs on the stock pump. if your running 3 bar base fuel, add 20 lbs of boost and thatll be just about the limits of the single walbro.

Why an flu when there is so much freeware and a chip burner is a couple bucks? Cost the same or more for a damn fmu. Do it righ or don't bother. The fmu is just going to end up in a blown motor

that being said leave the stock in take pump and run a bosh 044 inline between the rail and filter best inline pump that dan handle alot of pressure

the gss342 is the HP pump so im not sure why the graphs are different. but either way, im still not confident you can run 8psi. 38psi base + 96psi (12 x 8) = 134psi total pressure. the pump is only flowing 7gph at that point