HomeForumsTechnical – GeneralFuel SystemsPressure Difference when changing Fuel Pumps

This topic contains 7 replies, has 4 voices, and was last updated by Profile photo of Marzella Marzella 2 years, 5 months ago.

Viewing 8 posts - 1 through 8 (of 8 total)
  • Author
    Posts
  • #17009
    Profile photo of DUF42L
    DUF42L
    Participant
    Member since: March 16, 2015
    Posts: 9
    Supporter

    Hi Guys,

    I’m wanting to change my fuel pump setup. Currently i am running a standard in-tank pump which feeds a Bosch 044 then off to a Regulator.

    I would like to swap out the in-tank pump with a new 460 LPH walbro, and possibly take off the bosch.

    What i am worried about is the operating pressures as the bosch flows at 72psi and walbro flows at 44psi.

    would i have to muck around with my regulator or could it be just a flat out swap. is there a certain operating pressure for the injectors (or is that different for every set up)

    #17011
    Profile photo of Immortality
    Immortality
    Participant
    Member since: August 31, 2015
    Posts: 483

    The regulator sets the system pressure (unless something down stream of the regulator is restricting flow).

    Maybe what you are looking at is the rated flow at X pressure?

    Fuel injectors do have an ideal operating pressure and this would normally be the pressure at which it is rated, this is why it is important to have a 1:1  ratio manifold referenced FPR (so that the injector is working at the same constant pressure regardless of how much boost is put into the engine).

    Increasing the fuel pressure is one way of compensating for injectors that are to small and don’t flow enough, this works but only to a point as flow does not increase proportionately to pressure and if the pressures across the injector is to great then instead of getting a nice atomised stream of fuel it will just start to hose.  The newer style of injectors suffer much less and can handle much greater pressures but the original style EV1 injectors used in the VS era engines certainly don’t like to much pressure.

    #17012
    Profile photo of DUF42L
    DUF42L
    Participant
    Member since: March 16, 2015
    Posts: 9
    Supporter

    The regulator sets the system pressure (unless something down stream of the regulator is restricting flow).

    OK looks like i would be ok to swap out the pump as there is no other restrictions downstream. I also just found out that the walbro 460 pump flows 390lpm at 73psi which is pretty much the same operating pressure as the bosch 044 but with 90 more LPM i should be fine.

    FYI my engine is running seimens 60lb injectors and i might be upgrading them soon as well.

    Can’t wait to say goodbye to my noisy 044!!!

    #17013
    Profile photo of Immortality
    Immortality
    Participant
    Member since: August 31, 2015
    Posts: 483

    Do you know what the max duty cycle your injectors are running at?

    Those Deka 60lbs injectors are rated at 3 bar/43.5 psi.

    #17014
    Profile photo of DUF42L
    DUF42L
    Participant
    Member since: March 16, 2015
    Posts: 9
    Supporter

    they are running at 100% or close to it

     

    #17023
    Profile photo of cava454
    cava454
    Moderator
    Member since: February 20, 2015
    Posts: 2 030
    Supporter

    I’d be changing inj before pump.

    • This reply was modified 2 years, 5 months ago by Profile photo of cava454 cava454.
    #17025
    Profile photo of DUF42L
    DUF42L
    Participant
    Member since: March 16, 2015
    Posts: 9
    Supporter

    i was only going to change pump because my intank pump has shit itself. i am eyeing off a new set of injectors though.

    #17028
    Profile photo of Marzella
    Marzella
    Participant
    Member since: March 2, 2015
    Posts: 59

    Yes walbro will be fine, might want to run new bigger wiring to it.. Forget listed operating pressures, compare at your specific op pressures.

    FYI 044s are not noisy… It’s just how people mount them.

Viewing 8 posts - 1 through 8 (of 8 total)

You must be logged in to reply to this topic.