GrimmSpeed WR-STi AOS User Manual

GrimmSpeed Air/Oil Separator

Installation Instructions

Subaru 08+ WRX / ALL LGT Application

Manual 300020 RevB

All GrimmSpeed products are intended for Off-Road use only. Park your vehicle
on a level surface. Fully engage the parking brake and put wheel stops on the
front and rear wheels to keep the vehicle from rolling.

Warning (read before installing):

Before moving forward with the setups outlined below, insure that you have
the experience to properly modify your car. If not, please consult a
professional. Without a proper install you could possibly damage your engine.
Under no circumstances is the GrimmSpeed Air/Oil Separator to be used in any
applications where failure of the AOS to operate as intended could jeopardize
the safety of the operator or any other person or property.

NOTE: Our recommended method of installation retains the factory PCV valve.

Contents:
(1) AOS unit
(3) AOS Hose Fittings
(1) ½” to ½” to ½” Tee Hose Connector
(4) ½” to 5/8” Hose Connector
(1) 5/8” to 5/8” 90 Degree Elbow Hose Connector
(1) 5/8” Hose Cap
(1) 5/8” Hose Plug
(1) 1/2" Hose Cap
(1) 1/2" Hose Plug
(1) 8ft of ½” Hose
(1) 1ft of 3/8" Hose
(1) 1ft of 5/8” Hose
(20) Zip-ties

1. Install AOS fittings into AOS body. Place a drop of engine oil onto o-ring to ease installation.
Remove oil cap and install GrimmSpeed AOS so that fittings face towards the master cylinder.
Be careful to NOT over tighten the AOS into the oil fill.

2. Remove turbo to intercooler mounting bolts.

3. Remove BOV mounting bolts, remove IC mounting bolt, and loosen intercooler outlet hose
clamp. Remove intercooler.

4. Starting on the driver's side of the engine bay, locate cylinder head crossover tube and pull
rubber hose off of crossover tube.

5. Cut 2.5" of 5/8" ID hose (arrow 1 below) and push onto crossover tube. Push 5/8" to 1/2"
hose connector into the 2.5” of 5/8” hose. Push 1/2" hose (arrow 2 below) into other end of
the connector and then run the hose to the center port on the AOS, cut to length. We find that
using a small amount of water on the connector aids in pushing the hose on the plastic
connectors. Push 1/2” hose onto the AOS center fitting.