So, aparently my last thread got deleted for no apparent reason..or maybe it was an "accident".....who knows..anyways, I am just needing to know..if you have larger injectors, a MS system, and a walbro pump....why do you need a 1:1 FMU.....i see many people are running them..but i'm wanting to know why they are running them.....arent the larger injectors and MS taing care of all the fuel needs already....also, if you're messing with the fuel pressure at all levels of boost, then it's hard to get a good tuned fuel map...I just need some info on this ASAP please...

The 1:1 FMU is used to counteract the rising manifold
pressure.  Think of it this way; if you have 10PSI of boost
inside the manifold and 50psi of fuel pressure, it's the same
as having no boost in the manifold and 40psi of fuel pressure.
 The injectors have to have more pressure behind them to keep
the air from 'pushing back' against the incoming fuel.

As far as your map is concerned, you shouldn't ever notice it.
 But if you're running significant boost, you'll certainly
notice it if you don't have one later on.

so theoretically, if i were to run 40 psi of
boost.....then...really i would not see any fuel go into the
engine.......makes sense if i get what you are saying.....but
i really appreciate the SOLID answer you gave me..thnaks alot!

Your post was deleted because you fail to obsearve the rules
and we are tired of moving things around for you.  You had 2
posts (I deleted 1 regardless of contect) with the same title
and both in the wrong section.  Then you post this in the
wrong section.

Failure to obsearve the rules and proper thread psoting in
correct forums will result in you not being allowed to post.