Super Cheap Auto Castrol Edge Michelin Go Fast Bits Shannons Insurance Haltech Ryobi Century Batteries WD-40 KYB NTK NGK Spark Plugs

Announcement

Collapse
No announcement yet.

help with fuel pressure regulator upgrade

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • help with fuel pressure regulator upgrade

    Hi,

    im needing to upgrade my fuel pressure regulator, the one i have is located on the fuel pump housing (pictures below). the fuel pressure regulator itself has a fitting with an oring that sits in the housing and feeds from the outer filter/sock up the orange tube. Im totally confused by this as all the things I've seen online all the fuel regulators are in the engine bay. Would there be any way to bypass this? or could i get an adapter and put a hose on it and relocate the regulator in the engine?

    https://imgur.com/a/UeniAfZ

  • #2
    99% of the time, FPR in tank means this is a dead-head system (like on Benny's Stagea).
    So the fuel is regulated before it leaves the pump, then is sent up the line at an exact pressure, and anything sent, is burned, there is no return from the rail.

    Yes, you can bypass it, you'll need an aftermarket fuel rail (because you'll need a return port), a length of fuel hose, a bulkhead adaptor, a fuel pressure regulator, and a drill.

    Basically, replace the fuel rail, and plumb up your regulator in the engine bay.
    Run the fuel hose somewhere safe under the car, back to the tank.
    Drill a hole in the fuel pump cradle and install your bulkhead adaptor (make sure to use a fuel proof sealant also)
    Connect the fuel line.

    Here's a DIY guide from a DC5, which is another car that has a dead-head fuel system. The process will be almost identical.
    https://www.clubrsx.com/threads/d-i-...l-line.761326/

    If I've been wrong and it's not dead-head, then wtf are they doing with an FPR in the tank? lol.
    You could just completely remove it, cut the factory return line, and install an aftermarket.

    Keep in mind the only reason you need to upgrade a deadhead FPR is if you're greatly increasing the boost.
    Lets say it gives you 55psi of fuel pressure.
    If you run 12psi of boost, you now have that pressure working against the fuel line (when the injectors open), so the injectors only see 43psi of fuel pressure.

    Anything above 40psi gets a little 'sloppy' but is still tunable if the tuner knows that fuel line pressure is going to drop; he'll just compensate with more injector duty.

    Comment


    • #3
      Originally posted by Master_Scythe View Post
      99% of the time, FPR in tank means this is a dead-head system (like on Benny's Stagea).
      So the fuel is regulated before it leaves the pump, then is sent up the line at an exact pressure, and anything sent, is burned, there is no return from the rail.

      Yes, you can bypass it, you'll need an aftermarket fuel rail (because you'll need a return port), a length of fuel hose, a bulkhead adaptor, a fuel pressure regulator, and a drill.

      Basically, replace the fuel rail, and plumb up your regulator in the engine bay.
      Run the fuel hose somewhere safe under the car, back to the tank.
      Drill a hole in the fuel pump cradle and install your bulkhead adaptor (make sure to use a fuel proof sealant also)
      Connect the fuel line.

      Here's a DIY guide from a DC5, which is another car that has a dead-head fuel system. The process will be almost identical.
      https://www.clubrsx.com/threads/d-i-...l-line.761326/

      If I've been wrong and it's not dead-head, then wtf are they doing with an FPR in the tank? lol.
      You could just completely remove it, cut the factory return line, and install an aftermarket.

      Keep in mind the only reason you need to upgrade a deadhead FPR is if you're greatly increasing the boost.
      Lets say it gives you 55psi of fuel pressure.
      If you run 12psi of boost, you now have that pressure working against the fuel line (when the injectors open), so the injectors only see 43psi of fuel pressure.

      Anything above 40psi gets a little 'sloppy' but is still tunable if the tuner knows that fuel line pressure is going to drop; he'll just compensate with more injector duty.
      Thats super informative thanks! Im gonna see what the pressure is like im putting a higher flow fuel pump in (walbro 255)Im hoping it will be enough but who knows until you test it.
      ​​

      Comment


      • #4
        Pressure won't change with a 255, you'll just bypass more fuel; Which will make the fuel hotter.
        It's actually quite important you don't run too much more fuel pump than you need so you dont overwork\overheat the regulator or even heat the fuel itself.

        My mate put a 450Lph in his BMW M3, and blew it up; fuel got too hot and all the injectors seized open. Fuel Hydrolock.

        If you're seeing fuel issues, or your math for your new injectors suggest you will need a pump, then sure, a 255 isn't a huge pump, usually there's no issues even on stock injectors, so long as you're working them to their max.

        For example, K24's come with 310cc injectors, and they only use about 250cc even on VTEC at redline; so the stock fuel pump and injectors still have like 20% in them.
        Even THEN, MOST stock fuel pumps will flow close to 100LPH, meaning you can go up to 400CC injectors (actually; 416.5.... but headroom) without upgrading a pump.

        Walbro make a drop-in 190Lph, which is usually a good upgrade from the stock 90-120Lph that most cars ship with; just be sure to do your math before deciding.

        For example, 4x 1000cc injectors at stock fuel pressure, won't outflow a 255; so you'd want to be running something close to 1000CC injectors to warrant that much flow.

        190Lph, means 3.16Lpm, divide by 4cyl, means 791.5cc injectors.
        710cc is a common injector size; would easily be fed by that 190Lph pump.
        Last edited by Master_Scythe; 26-10-2020, 11:56 AM.

        Comment

        Working...
        X