315150 - COBB Fuel Pressure Regulator Manifold Reference Reclocation Kit



 COBB Fuel Pressure Regulator Manifold Reference Relocation Kit

Subaru WRX STi 2008 - 2021


Congratulations on your purchase of the COBB Tuning Fuel Pressure Regulator Manifold Reference Relocation Kit for your 2008+ Subaru STI! The following instructions will assist you through your installation process. Please read them first BEFORE beginning the install and familiarize yourself with the steps and tools needed. If you feel that you cannot properly perform this installation, we HIGHLY recommend you take the vehicle to a qualified and experienced automotive technician.
IMPORTANT!  Installing this kit will require custom tuning or utilizing an appropriate Stage Power Package map that includes this kit.  Please consult with COBB or an authorized ProTuner in your area

Part List

  • 6 x Small Zip Ties
  • 1 x Manifold Reference Relocation "Tee"
  • 1 x Small Black Vacuum Cap
  • 1 x Section of 6mm black silicone hose (Tee to FPR line)
  • 1 x Section of 4mm black silicone hose (Tee to BPV line)

Tools Needed

  • Pliers 
  • Diagonal Cutters or Scissors (Hose Cutting tools suggested for straight cuts)
  • Rags
  • Silicone Spray or Similar

IMPORTANT!  Installing this kit will require custom tuning or utilizing an appropriate Stage Power Package map that includes this kit.  Please consult with COBB or an authorized ProTuner in your area.


Installation of COBB Fuel Pressure Regulator Manifold Reference Relocation Kit

  1. Inspect the new components included with the COBB kit. If anything appears out of place, please contact COBB immediately and do not proceed with the installation.

  2. We now offer a “Manifold Reference Relocation Kit” with our FPR kit.  This allows for moving the fuel pressure regulator’s manifold pressure reference away from the #4 cylinder runner and into a plenum-based source, similar to the method used on the previous generation 2004-2007 STI.  This helps prevent unwanted manifold pulsations from affecting the FPR as the plenum is a “common” area of the manifold that represents the average vacuum/boost of all cylinders rather than a singular cylinder. 

  3. To install the Manifold Reference Relocation kit, remove and set aside the factory rubber hose connected to the small nipple on the intake manifold runner for Cylinder #4 and the fuel pressure regulator.  If the vehicle is equipped with an auxiliary boost gauge, like those offered as factory STI/SPT options or an aftermarket unit, we recommend that you now connect those devices directly to this port.  Vehicles utilizing Hobbs switches and other similar devices that need a vacuum/boost reference can also be plumbed to this port.  If no other devices are connected to the manifold for detecting boost/vacuum, you may cap this port with the included black vacuum cap.  WARNING: Black rubber vacuum caps can deteriorate over time and eventually cause leaking.  PLEASE INSPECT THIS PIECE FREQUENTLY AND REPLACE IF SIGNS OF DEGRADATION ARE PRESENT!  Replacements can be sourced from COBB Tuning or any local automotive parts store.

  4. Cut the OEM bypass valve (BPV) reference hose near the BPV but with adequate material left to allow easy insertion of the new COBB-provided “Tee” fitting.  The larger ports will connect to the OEM hose on one side and back to the BPV on the other side using the provided 6mm black silicone hose; the small “Tee” port will now connect directly to the FPR using the provided 4mm black silicone hose.  Trim hoses as necessary to allow for shortest length necessary to easily reach all components without being stretched or pinched.

  5. Installation of the Fuel Pressure Regulator Manifold Reference Relocation Kit is now complete!  IMPORTANT!  Retuning is HIGHLY suggested to account for the newly corrected fuel system under cruising conditions.  Please consult with COBB or an authorized Pro-Tuner in your area.  We recommend inspecting for any signs of component deterioration periodically for safety and performance purposes.  Enjoy your new COBB Tuning Fuel Pressure Regulator Manifold Reference Relocation Kit! 



COBB Product Install Instructions for Subaru Vehicles 

Main Installation Instruction Repository for Subaru Parts

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